Merge SoftFever's main-into-cad-mainline update

He merged upstream main into the PR branch himself on 2026-08-13. Taking it into
the local branch rather than force-pushing over it: the fork copy is what PR
#15238 shows, and discarding a maintainer's merge to make my own push
fast-forward would be both rude and a loss of 130 upstream commits.

Brings the branch far closer to main than the 2026-07-24 merge-base the PR body
describes, which is most of what snaporca-36u9 was filed for.

src/CMakeLists.txt

@@ -88,6 +88,10 @@ if (SLIC3R_GUI)
     list(FILTER wxWidgets_LIBRARIES EXCLUDE REGEX OpenGL)
 
 #    list(REMOVE_ITEM wxWidgets_LIBRARIES oleacc)
+
+    find_package(wxInspector REQUIRED)
+    list(APPEND wxWidgets_LIBRARIES "wxInspector::wxInspector")
+
     message(STATUS "wx libs: ${wxWidgets_LIBRARIES}")
 
     add_subdirectory(slic3r)

src/OrcaSlicer.cpp

@@ -7054,7 +7054,7 @@ int CLI::run(int argc, char **argv)
             gcode_viewer.render_calibration_thumbnail(*calibration_data, cali_thumbnail_width, cali_thumbnail_height,
                 calibration_params, partplate_list, opengl_mgr);
             //generate_calibration_thumbnail(*calibration_data, thumbnail_width, thumbnail_height, calibration_params);
-            //*plate_bboxes[index] = p->generate_first_layer_bbox();
+            // *plate_bboxes[index] = p->generate_first_layer_bbox();
             calibration_thumbnails.push_back(calibration_data);*/
 
             PlateBBoxData* plate_bbox = new PlateBBoxData();

src/libslic3r/AABBMesh.cpp

@@ -54,12 +54,12 @@ public:
                             int &                        i,
                             Eigen::Matrix<double, 1, 3> &closest)
     {
-        size_t idx_unsigned = 0;
-        Vec3d  closest_vec3d(closest);
-        double dist =
+        size_t idx_unsigned { 0 };
+        Vec3d  closest_vec3d { Vec3d::Zero() };
+        const double dist {
             AABBTreeIndirect::squared_distance_to_indexed_triangle_set(
                 its.vertices, its.indices, m_tree, point, idx_unsigned,
-                closest_vec3d);
+                closest_vec3d) };
         i       = int(idx_unsigned);
         closest = closest_vec3d;
         return dist;
@@ -311,10 +311,9 @@ AABBMesh::hit_result IndexedMesh::filter_hits(
 
 
 double AABBMesh::squared_distance(const Vec3d &p, int& i, Vec3d& c) const {
-    double sqdst = 0;
-    Eigen::Matrix<double, 1, 3> pp = p;
-    Eigen::Matrix<double, 1, 3> cc;
-    sqdst = m_aabb->squared_distance(*m_tm, pp, i, cc);
+    const Eigen::Matrix<double, 1, 3> pp { p };
+    Eigen::Matrix<double, 1, 3> cc { Vec3d::Zero() };
+    const double sqdst { m_aabb->squared_distance(*m_tm, pp, i, cc) };
     c = cc;
     return sqdst;
 }

src/libslic3r/AABBTreeLines.hpp

@@ -31,8 +31,9 @@ namespace AABBTreeLines {
             inline VectorType closest_point_to_origin(size_t primitive_index, ScalarType& squared_distance) const
             {
                 Vec<LineType::Dim, typename LineType::Scalar> nearest_point;
+                Vec<LineType::Dim, typename LineType::Scalar> cast_origin = origin.template cast<typename LineType::Scalar>();
                 const LineType& line = lines[primitive_index];
-                squared_distance = line_alg::distance_to_squared(line, origin.template cast<typename LineType::Scalar>(), &nearest_point);
+                squared_distance = line_alg::distance_to_squared(line, cast_origin, &nearest_point);
                 return nearest_point.template cast<ScalarType>();
             }
         };

src/libslic3r/AppConfig.cpp

@@ -202,10 +202,25 @@ void AppConfig::set_defaults()
     if (get("seq_top_layer_only").empty())
         set("seq_top_layer_only", "1");
 
-    // ORCA: darken layers below the current one while scrubbing the preview (ported from preFlight)
+    // ORCA: darken the layers the preview layer slider is not scrubbed to
     if (get("preview_dim_previous_layers").empty())
         set_bool("preview_dim_previous_layers", false);
 
+    // ORCA: brightness of those dimmed layers, in percent. 0 = black, capped at 99 because
+    // 100 would render them unchanged, which is what disabling the option already does
+    if (get("preview_dim_previous_layers_brightness").empty())
+        set("preview_dim_previous_layers_brightness", "40");
+    else {
+        int brightness = 40;
+        try {
+            brightness = std::stoi(get("preview_dim_previous_layers_brightness"));
+        }
+        catch (...) {
+            brightness = 40;
+        }
+        set("preview_dim_previous_layers_brightness", std::to_string(std::max(0, std::min(brightness, 99))));
+    }
+
     if (get("filaments_area_preferred_count").empty())
         set("filaments_area_preferred_count", "10");
 
@@ -611,6 +626,12 @@ void AppConfig::set_defaults()
         set_bool("window_buttons_on_left", false);
 #endif
 
+    if (get("use_printer_agents").empty())
+    {
+        // false = legacy behavior using print hosts
+        set_bool("use_printer_agents", false);
+    }
+
     // Remove legacy window positions/sizes
     erase("app", "main_frame_maximized");
     erase("app", "main_frame_pos");
@@ -862,7 +883,7 @@ std::string AppConfig::load()
                 }
             }
         }
-    } catch(std::exception err) {
+    } catch(const std::exception &err) {
         BOOST_LOG_TRIVIAL(info) << format("parse app config \"%1%\", error: %2%", AppConfig::loading_path(), err.what());
 
         return err.what();

src/libslic3r/Arachne/WallToolPaths.hpp

@@ -23,14 +23,14 @@ inline coord_t    meshfix_maximum_extrusion_area_deviation() { return scaled<coo
 class WallToolPathsParams
 {
 public:
-    float   min_bead_width;
-    float   min_feature_size;
-    float   min_length_factor;
-    float   wall_transition_length;
-    float   wall_transition_angle;
-    float   wall_transition_filter_deviation;
-    int     wall_distribution_count;
-    bool    is_top_or_bottom_layer;
+    float   min_bead_width                   = 0.f;
+    float   min_feature_size                 = 0.f;
+    float   min_length_factor                = 0.5f;
+    float   wall_transition_length           = 0.f;
+    float   wall_transition_angle            = 10.f;
+    float   wall_transition_filter_deviation = 0.f;
+    int     wall_distribution_count          = 1;
+    bool    is_top_or_bottom_layer           = false;
 
     coord_t wall_maximum_resolution = meshfix_maximum_resolution();
     coord_t wall_maximum_deviation  = meshfix_maximum_deviation();

src/libslic3r/BoundingBox.hpp

@@ -25,7 +25,7 @@ public:
         min(p1), max(p1), defined(false) { merge(p2); merge(p3); }
 
     template<class It, class = IteratorOnly<It>>
-    BoundingBoxBase(It from, It to)
+    BoundingBoxBase(It from, It to) : BoundingBoxBase()
         { construct(*this, from, to); }
 
     BoundingBoxBase(const PointsType &points)

src/libslic3r/Brim.cpp

@@ -32,15 +32,13 @@ static void append_and_translate(ExPolygons &dst, const ExPolygons &src, const P
     for (; dst_idx < dst.size(); ++dst_idx)
         dst[dst_idx].translate(instance_shift);
 }
-// BBS: generate brim area by objs
-static void append_and_translate(ExPolygons& dst, const ExPolygons& src,
-    const PrintInstance& instance, size_t instance_idx, std::map<ObjectInstanceID, ExPolygons>& brimAreaMap) {
+// Orca: Translate the brim area into print coordinates and store it per instance.
+static void append_and_translate(const ExPolygons& src, const PrintInstance& instance,
+    size_t instance_idx, std::map<ObjectInstanceID, ExPolygons>& brimAreaMap) {
     ExPolygons srcShifted = src;
     Point instance_shift = instance.shift_without_plate_offset();
-    for (size_t src_idx = 0; src_idx < srcShifted.size(); ++src_idx)
-        srcShifted[src_idx].translate(instance_shift);
-    srcShifted = diff_ex(srcShifted, dst);
-    //expolygons_append(dst, temp2);
+    for (ExPolygon& expoly : srcShifted)
+        expoly.translate(instance_shift);
     expolygons_append(brimAreaMap[{ instance.print_object->id(), instance_idx }], std::move(srcShifted));
 }
 
@@ -351,7 +349,7 @@ static ExPolygons make_brim_ears_auto(const ExPolygons& obj_expoly, coord_t size
     return mouse_ears_ex;
 }
 
-static ExPolygons make_brim_ears(const PrintObject* object, const double& flowWidth, float brim_offset, Flow &flow, bool is_outer_brim)
+static ExPolygons make_brim_ears(const PrintObject* object)
 {
     ExPolygons mouse_ears_ex;
     BrimPoints brim_ear_points = object->model_object()->brim_points;
@@ -375,12 +373,7 @@ static ExPolygons make_brim_ears(const PrintObject* object, const double& flowWi
         Vec3f world_pos = pt.transform(trsf.get_matrix());
         if ( world_pos.z() > 0) continue;
         Polygon point_round;
-        float brim_width = floor(scale_(pt.head_front_radius) / flowWidth / 2) * flowWidth * 2;
-        if (is_outer_brim) {
-            double flowWidthScale = flowWidth / SCALING_FACTOR;
-            brim_width = floor(brim_width / flowWidthScale / 2) * flowWidthScale * 2;
-        }
-        coord_t size_ear = (brim_width - brim_offset - flow.scaled_spacing());
+        const coord_t size_ear = scale_(pt.head_front_radius);
         for (size_t i = 0; i < POLY_SIDE_COUNT; i++) {
             double angle = (2.0 * PI * i) / POLY_SIDE_COUNT;
             point_round.points.emplace_back(size_ear * cos(angle), size_ear * sin(angle));
@@ -454,7 +447,8 @@ static ExPolygons outer_inner_brim_area(const Print& print,
             bool               has_brim_auto = object->config().brim_type == btAutoBrim;
             const bool         use_auto_brim_ears = object->config().brim_type == btEar;
             const bool         use_brim_ears = object->config().brim_type == btPainted;
-            const bool         has_inner_brim = brim_type == btInnerOnly || brim_type == btOuterAndInner || use_auto_brim_ears || use_brim_ears;
+            const bool         use_inner_brim_ears = (use_auto_brim_ears || use_brim_ears) && !object->config().brim_ears_outer_only.value;
+            const bool         has_inner_brim = brim_type == btInnerOnly || brim_type == btOuterAndInner || use_inner_brim_ears;
             const bool         has_outer_brim = brim_type == btOuterOnly || brim_type == btOuterAndInner || brim_type == btAutoBrim || use_auto_brim_ears || use_brim_ears;
             coord_t            ear_detection_length = scale_(object->config().brim_ears_detection_length.value);
             coordf_t           brim_ears_max_angle = object->config().brim_ears_max_angle.value;
@@ -533,7 +527,7 @@ static ExPolygons outer_inner_brim_area(const Print& print,
                                 auto innerExpoly = offset_ex(ex_poly.contour, brim_offset, jtRound, SCALED_RESOLUTION);
                                 ExPolygons outerExpoly;
                                 if (use_brim_ears) {
-                                    outerExpoly = make_brim_ears(object, flowWidth, brim_offset, flow, true);
+                                    outerExpoly = make_brim_ears(object);
                                     //outerExpoly = offset_ex(outerExpoly, brim_width_mod, jtRound, SCALED_RESOLUTION);
                                 } else if (use_auto_brim_ears) {
                                     coord_t size_ear = (brim_width_mod - brim_offset - flow.scaled_spacing());
@@ -547,7 +541,7 @@ static ExPolygons outer_inner_brim_area(const Print& print,
                                 ExPolygons outerExpoly;
                                 auto innerExpoly = offset_ex(ex_poly_holes_reversed, -brim_width - brim_offset);
                                 if (use_brim_ears) {
-                                    outerExpoly = make_brim_ears(object, flowWidth, brim_offset, flow, false);
+                                    outerExpoly = make_brim_ears(object);
                                 } else if (use_auto_brim_ears) {
                                     coord_t size_ear = (brim_width - brim_offset - flow.scaled_spacing());
                                     outerExpoly = make_brim_ears_auto(offset_ex(ex_poly_holes_reversed, -brim_offset), size_ear, ear_detection_length, brim_ears_max_angle, false);
@@ -572,7 +566,7 @@ static ExPolygons outer_inner_brim_area(const Print& print,
                 for (size_t instance_idx = 0; instance_idx < object->instances().size(); ++instance_idx) {
                     const PrintInstance& instance = object->instances()[instance_idx];
                     if (!brim_area_object.empty())
-                        append_and_translate(brim_area, brim_area_object, instance, instance_idx, brimAreaMap);
+                        append_and_translate(brim_area_object, instance, instance_idx, brimAreaMap);
                     append_and_translate(no_brim_area, no_brim_area_object, instance);
                     append_and_translate(holes, holes_object, instance);
                     append_and_translate(objectIslands, objectIsland, instance);
@@ -875,6 +869,14 @@ void make_brim(const Print& print, PrintTryCancel try_cancel, Polygons& islands_
     ExPolygons           islands_area_ex = outer_inner_brim_area(print,
         float(flow.scaled_spacing()), brimAreaMap, objPrintVec, printExtruders);
 
+    if (!print.config().combine_brims) {
+        ExPolygons claimed_area;
+        for (auto& [_, areas] : brimAreaMap) {
+            areas = diff_ex(areas, claimed_area);
+            expolygons_append(claimed_area, areas);
+        }
+    }
+
     // BBS: Find boundingbox of the first layer
     for (const ObjectID printObjID : print.print_object_ids()) {
         BoundingBox bbx;

src/libslic3r/CMakeLists.txt

@@ -253,6 +253,8 @@ set(lisbslic3r_sources
     GCode/Thumbnails.hpp
     GCode/ToolOrdering.cpp
     GCode/ToolOrdering.hpp
+    GCode/OrderingStrategies.cpp
+    GCode/OrderingStrategies.hpp
     GCode/WipeTower2.cpp
     GCode/WipeTower2.hpp
     GCode/WipeTower.cpp

src/libslic3r/Config.hpp

@@ -2,6 +2,7 @@
 #define slic3r_Config_hpp_
 
 #include <assert.h>
+#include <algorithm>
 #include <map>
 #include <climits>
 #include <cfloat>
@@ -780,10 +781,14 @@ public:
                 this->values[i] = rhs_vec->values[i];
                 modified        = true;
             } else {
-                if ((i < default_index.size()) && (default_index[i] < default_value.size()))
+                // Orca: a negative slot (failed variant lookup) must not silently collapse the
+                // whole array to the first slot's value — the int-vs-size_t comparison used to
+                // promote -1 past the bounds check. Keep the slot's own value (get_at-style
+                // clamp) when no valid index is available.
+                if ((i < default_index.size()) && (default_index[i] >= 0) && (size_t(default_index[i]) < default_value.size()))
                     this->values[i] = default_value[default_index[i]];
                 else
-                    this->values[i] = default_value[0];
+                    this->values[i] = default_value[std::min(i, default_value.size() - 1)];
             }
         }
         return modified;
@@ -2106,6 +2111,11 @@ public:
             throw ConfigurationError("ConfigOptionEnumGeneric: Assigning an incompatible type");
         // rhs could be of the following type: ConfigOptionEnumGeneric or ConfigOptionEnum<T>
         this->value = rhs->getInt();
+        // Orca: options embedded in a StaticPrintConfig are constructed without a keys_map;
+        // adopt the source's so a later serialize() can emit names.
+        if (this->keys_map == nullptr)
+            if (auto rhs_generic = dynamic_cast<const ConfigOptionEnumGeneric *>(rhs))
+                this->keys_map = rhs_generic->keys_map;
     }
 
     std::string serialize() const override
@@ -2162,7 +2172,12 @@ public:
         if (rhs->type() != this->type())
             throw ConfigurationError("ConfigOptionEnumGeneric: Assigning an incompatible type");
         // rhs could be of the following type: ConfigOptionEnumsGeneric
-        this->values = dynamic_cast<const ConfigOptionEnumsGenericTempl *>(rhs)->values;
+        auto rhs_enums = dynamic_cast<const ConfigOptionEnumsGenericTempl *>(rhs);
+        this->values = rhs_enums->values;
+        // Orca: options embedded in a StaticPrintConfig are constructed without a keys_map;
+        // adopt the source's so a later serialize() emits names instead of empty tokens.
+        if (this->keys_map == nullptr)
+            this->keys_map = rhs_enums->keys_map;
     }
 
     std::string serialize() const override
@@ -2258,6 +2273,8 @@ public:
         plugin_picker,
         // Raw JSON string value, edited through a dialog behind a button rather than in the row.
         plugin_config,
+        // PrinterAgentChoice
+        printer_agent_select,
     };
 
 	// Identifier of this option. It is stored here so that it is accessible through the by_serialization_key_ordinal map.

src/libslic3r/Extruder.cpp

@@ -220,12 +220,12 @@ double Extruder::retract_restart_extra() const
 
 double Extruder::retract_length_toolchange() const
 {
-    return m_config->retract_length_toolchange.get_at(extruder_id());
+    return m_config->retract_length_toolchange.get_at(m_config_index);
 }
 
 double Extruder::retract_restart_extra_toolchange() const
 {
-    return m_config->retract_restart_extra_toolchange.get_at(extruder_id());
+    return m_config->retract_restart_extra_toolchange.get_at(m_config_index);
 }
 
 double Extruder::travel_slope() const

src/libslic3r/Fill/Fill.cpp

@@ -278,6 +278,9 @@ struct SurfaceFillParams
     // For Gyroid: when true, use the parameterized "optimized" wave.
     bool gyroid_optimized = false;
 
+    // Orca: corner smoothing factor in the range [0, 1].
+    double      smooth_factor { 0. };
+
     CenterOfSurfacePattern center_of_surface_pattern{CenterOfSurfacePattern::Each_Surface};
     bool                   separated_infills{false};
 
@@ -316,6 +319,7 @@ struct SurfaceFillParams
 		RETURN_COMPARE_NON_EQUAL(skin_infill_depth);
         RETURN_COMPARE_NON_EQUAL(infill_overhang_angle);
 		RETURN_COMPARE_NON_EQUAL(gyroid_optimized);
+        RETURN_COMPARE_NON_EQUAL(smooth_factor);
         RETURN_COMPARE_NON_EQUAL(center_of_surface_pattern);
         RETURN_COMPARE_NON_EQUAL(separated_infills);
 		RETURN_COMPARE_NON_EQUAL_TYPED(unsigned, fill_order);
@@ -348,6 +352,7 @@ struct SurfaceFillParams
                 this->center_of_surface_pattern == rhs.center_of_surface_pattern &&
                 this->separated_infills       == rhs.separated_infills &&
                 this->gyroid_optimized        == rhs.gyroid_optimized        &&
+                this->smooth_factor           == rhs.smooth_factor           &&
                 this->fill_order              == rhs.fill_order;
 	}
 };
@@ -964,6 +969,11 @@ std::vector<SurfaceFill> group_fills(const Layer &layer, LockRegionParam &lock_p
                     params.angle = calculate_infill_rotation_angle(layer.object(), layer.id(), region_config.infill_direction.value,
                                                                    region_config.sparse_infill_rotate_template.value);
                     params.fixed_angle = !region_config.sparse_infill_rotate_template.value.empty();
+
+                    // Orca: special case; apply smoothing factor only for Hilbert Curve sparse infill.
+                    // FillHilbertCurve::generate clamps and validates the value itself.
+                    if (params.pattern == ipHilbertCurve)
+                        params.smooth_factor = 0.01 * region_config.sparse_infill_smooth_factor.value;
                 } else {
                     const bool top_layer_direction_set    = surface.is_top() && region_config.top_layer_direction.value >= 0.;
                     const bool bottom_layer_direction_set = surface.is_bottom() && region_config.bottom_layer_direction.value >= 0.;
@@ -1328,6 +1338,7 @@ void Layer::make_fills(FillAdaptive::Octree* adaptive_fill_octree, FillAdaptive:
         params.lateral_lattice_angle_2   = surface_fill.params.lateral_lattice_angle_2;
         params.infill_overhang_angle   = surface_fill.params.infill_overhang_angle;
         params.gyroid_optimized          = surface_fill.params.gyroid_optimized;
+        params.smooth_factor             = surface_fill.params.smooth_factor;
 
 		// BBS
 		params.flow = surface_fill.params.flow;
@@ -1569,6 +1580,7 @@ Polylines Layer::generate_sparse_infill_polylines_for_anchoring(FillAdaptive::Oc
         params.infill_overhang_angle   = surface_fill.params.infill_overhang_angle;
         params.multiline         = surface_fill.params.multiline;
         params.gyroid_optimized          = surface_fill.params.gyroid_optimized;
+        params.smooth_factor             = surface_fill.params.smooth_factor;
 
         for (ExPolygon &expoly : surface_fill.expolygons) {
             // Spacing is modified by the filler to indicate adjustments. Reset it for each expolygon.

src/libslic3r/Fill/FillBase.cpp

@@ -1857,12 +1857,12 @@ static inline void base_support_extend_infill_lines(Polylines &infill, BoundaryI
         const bool                   first           = graph.first(cp);
         int                          extend_next_idx = -1;
         int                          extend_prev_idx = -1;
-        coord_t                      dist_y_prev;
-        coord_t                      dist_y_next;
-        double                       arc_len_prev;
-        double                       arc_len_next;
+        coord_t                      dist_y_prev     = 0;
+        coord_t                      dist_y_next     = 0;
+        double                       arc_len_prev    = 0;
+        double                       arc_len_next    = 0;
 
-        if (! graph.next_vertical(cp)){
+        if (! graph.next_vertical(cp)) {
             size_t i = cp.point_idx;
             size_t j = next_idx_modulo(i, contour);
             while (j != cp.next_on_contour->point_idx) {

src/libslic3r/Fill/FillBase.hpp

@@ -82,6 +82,9 @@ struct FillParams
     // For Gyroid: when true, use the parameterized "optimized" variant.
     bool        gyroid_optimized { false };
 
+    // Orca: corner smoothing factor in the range [0, 1].
+    double      smooth_factor { 0. };
+
     // For Lateral lattice
     coordf_t    lateral_lattice_angle_1    { 0.f };
     coordf_t    lateral_lattice_angle_2    { 0.f };

src/libslic3r/Fill/FillPlanePath.cpp

@@ -114,12 +114,12 @@ void FillPlanePath::_fill_surface_single(
             // Filling in a bounding box over the whole object, clip generated polyline against the snug bounding box.
             snug_bounding_box.translate(-shift.x(), -shift.y());
             InfillPolylineClipper output(snug_bounding_box, distance_between_lines);
-            this->generate(min_x, min_y, max_x, max_y, resolution, output);
+            this->generate(min_x, min_y, max_x, max_y, resolution, params, output);
             polyline.points = std::move(output.result());
         } else {
             // Filling in a snug bounding box, no need to clip.
             InfillPolylineOutput output(distance_between_lines);
-            this->generate(min_x, min_y, max_x, max_y, resolution, output);
+            this->generate(min_x, min_y, max_x, max_y, resolution, params, output);
             polyline.points = std::move(output.result());
         }
     }
@@ -288,6 +288,147 @@ static void generate_hilbert_curve(coord_t min_x, coord_t min_y, coord_t max_x,
     }
 }
 
+using QuinticBezier = std::array<Vec2d, 6>;
+
+static bool is_bezier_flat(const QuinticBezier &curve, const double deviation)
+{
+    // A Bezier curve stays inside the convex hull of its control points. Therefore, keeping every
+    // control point within a deviation-wide strip around the endpoint chord conservatively bounds the
+    // flattening error. The cross product is the perpendicular distance scaled by the chord length;
+    // comparing squared values avoids a square root.
+    const Vec2d  chord           = curve.back() - curve.front();
+    const double chord_length_sq = chord.squaredNorm();
+    const double max_cross_sq    = deviation * deviation * chord_length_sq;
+
+    for (size_t i = 1; i + 1 < curve.size(); ++i) {
+        const Vec2d  offset = curve[i] - curve.front();
+        const double cross  = chord.x() * offset.y() - chord.y() * offset.x();
+        if (cross * cross > max_cross_sq)
+            return false;
+    }
+    return true;
+}
+
+static void subdivide_bezier(const QuinticBezier &curve, QuinticBezier &left, QuinticBezier &right)
+{
+    // Split the curve at t = 0.5 using de Casteljau's algorithm. Each averaging level contributes one
+    // control point to the left half and one to the right half; the latter is filled backwards to keep
+    // both resulting control polygons in their original parameter direction.
+    QuinticBezier subdivision = curve;
+    left.front() = subdivision.front();
+    right.back() = subdivision.back();
+    for (size_t level = 1; level < curve.size(); ++level) {
+        for (size_t i = 0; i + level < curve.size(); ++i)
+            subdivision[i] = 0.5 * (subdivision[i] + subdivision[i + 1]);
+        left[level] = subdivision.front();
+        right[curve.size() - level - 1] = subdivision[curve.size() - level - 1];
+    }
+}
+
+static void flatten_bezier(const QuinticBezier &curve, const double deviation, std::vector<Vec2d> &output)
+{
+    // Subdivide to at least depth 1 so a rounded corner cannot collapse to a single diagonal chord.
+    // A uniform subdivision depth keeps samples at equal parameter intervals t = k / 2^depth,
+    // avoiding abrupt segment-length jumps at adaptive-depth boundaries.
+    static constexpr size_t max_depth = 16;
+
+    std::vector<QuinticBezier> subcurves(2);
+    subdivide_bezier(curve, subcurves[0], subcurves[1]);
+
+    for (size_t depth = 1; depth < max_depth; ++depth) {
+        bool all_flat = true;
+        for (const QuinticBezier &c : subcurves)
+            if (!is_bezier_flat(c, deviation)) {
+                all_flat = false;
+                break;
+            }
+        if (all_flat)
+            break;
+        std::vector<QuinticBezier> finer(subcurves.size() * 2);
+        for (size_t i = 0; i < subcurves.size(); ++i)
+            subdivide_bezier(subcurves[i], finer[i * 2], finer[i * 2 + 1]);
+        subcurves = std::move(finer);
+    }
+
+    // The curve start is deliberately omitted so consecutive curve pieces can share it without duplication.
+    output.reserve(output.size() + subcurves.size());
+    for (const QuinticBezier &c : subcurves)
+        output.emplace_back(c.back());
+}
+
+template<typename Output>
+static void generate_smooth_hilbert_curve(
+    coord_t min_x, coord_t min_y, coord_t max_x, coord_t max_y, const double resolution,
+    const double corner_distance, Output &output)
+{
+    // A Hilbert curve is defined on a square grid whose side is a power of two. As in the unsmoothed
+    // generator, expand the larger requested dimension to the next valid Hilbert grid size. The output
+    // clipper or the later region intersection removes the padded part of the traversal.
+    size_t sz = 2;
+    const size_t sz0 = std::max(max_x + 1 - min_x, max_y + 1 - min_y);
+    while (sz < sz0)
+        sz <<= 1;
+
+    const size_t point_count = sz * sz;
+    output.reserve(point_count);
+
+    // The caller normalizes resolution to the unit Hilbert grid; retain a finite positive tolerance
+    // if this helper is invoked with an invalid resolution.
+    const double deviation = resolution > 0. && std::isfinite(resolution) ? resolution : EPSILON;
+    // Construct one canonical 90-degree corner from (-corner_distance, 0) to (0, corner_distance).
+    // At each end, the first three control points are collinear and equally spaced: the tangent follows
+    // the adjoining straight leg and the second derivative is zero. The endpoint curvature is therefore
+    // zero, giving G2 joins to both legs. Every Hilbert turn is an oriented copy of this curve, so flatten
+    // it only once to the requested chordal-deviation tolerance.
+    const QuinticBezier corner_curve {{
+        {-corner_distance, 0.}, {-0.7 * corner_distance, 0.}, {-0.4 * corner_distance, 0.},
+        {0., 0.4 * corner_distance}, {0., 0.7 * corner_distance}, {0., corner_distance}
+    }};
+    std::vector<Vec2d> curve_coefficients;
+    flatten_bezier(corner_curve, deviation, curve_coefficients);
+
+    auto translated_point = [min_x, min_y](size_t idx) {
+        Point p = hilbert_n_to_xy(idx);
+        return Point(p.x() + min_x, p.y() + min_y);
+    };
+    auto to_vec2d = [](const Point &p) { return Vec2d(double(p.x()), double(p.y())); };
+    bool has_last_output = false;
+    Vec2d last_output;
+    // Fully smoothed adjacent corners may meet at the same segment midpoint. Suppress such duplicates
+    // to avoid emitting zero-length extrusion segments.
+    auto add_point = [&output, &has_last_output, &last_output](const Vec2d &point) {
+        if (!has_last_output || point.x() != last_output.x() || point.y() != last_output.y()) {
+            output.add_point(point);
+            last_output     = point;
+            has_last_output = true;
+        }
+    };
+
+    Vec2d previous = to_vec2d(translated_point(0));
+    Vec2d corner   = to_vec2d(translated_point(1));
+    add_point(previous);
+    // Replace each non-collinear Hilbert vertex by the canonical curve expressed in the local basis of
+    // its incoming and outgoing unit vectors. Collinear vertices remain part of the straight polyline.
+    for (size_t i = 1; i + 1 < point_count; ++i) {
+        const Vec2d next     = to_vec2d(translated_point(i + 1));
+        const Vec2d incoming = (corner - previous).normalized();
+        const Vec2d outgoing = (next - corner).normalized();
+        const double cross   = incoming.x() * outgoing.y() - incoming.y() * outgoing.x();
+
+        if (std::abs(cross) < EPSILON) {
+            add_point(corner);
+        } else {
+            add_point(corner - corner_distance * incoming);
+            for (const Vec2d &coefficient : curve_coefficients)
+                add_point(corner + coefficient.x() * incoming + coefficient.y() * outgoing);
+        }
+
+        previous = corner;
+        corner   = next;
+    }
+    add_point(corner);
+}
+
 void FillHilbertCurve::generate(coord_t min_x, coord_t min_y, coord_t max_x, coord_t max_y, const double /* resolution */, InfillPolylineOutput &output)
 {
     if (output.clips())
@@ -296,6 +437,24 @@ void FillHilbertCurve::generate(coord_t min_x, coord_t min_y, coord_t max_x, coo
         generate_hilbert_curve(min_x, min_y, max_x, max_y, output);
 }
 
+void FillHilbertCurve::generate(coord_t min_x, coord_t min_y, coord_t max_x, coord_t max_y, const double resolution,
+    const FillParams &params, InfillPolylineOutput &output)
+{
+    const double smooth_factor = std::isfinite(params.smooth_factor) ?
+        std::clamp(params.smooth_factor, 0., 1.) : 0.;
+    if (smooth_factor == 0.) {
+        this->generate(min_x, min_y, max_x, max_y, resolution, output);
+        return;
+    }
+
+    const double corner_distance = 0.5 * smooth_factor;
+    if (output.clips())
+        generate_smooth_hilbert_curve(
+            min_x, min_y, max_x, max_y, resolution, corner_distance, static_cast<InfillPolylineClipper&>(output));
+    else
+        generate_smooth_hilbert_curve(min_x, min_y, max_x, max_y, resolution, corner_distance, output);
+}
+
 template<typename Output>
 static void generate_octagram_spiral(coord_t min_x, coord_t min_y, coord_t max_x, coord_t max_y, Output &output)
 {

src/libslic3r/Fill/FillPlanePath.hpp

@@ -53,6 +53,11 @@ protected:
     friend class InfillPolylineClipper;
     
     virtual void generate(coord_t min_x, coord_t min_y, coord_t max_x, coord_t max_y, const double resolution, InfillPolylineOutput &output) = 0;
+    virtual void generate(coord_t min_x, coord_t min_y, coord_t max_x, coord_t max_y, const double resolution,
+                                      const FillParams & /* params */, InfillPolylineOutput &output)
+    {
+        this->generate(min_x, min_y, max_x, max_y, resolution, output);
+    }
 };
 
 class FillArchimedeanChords : public FillPlanePath
@@ -75,6 +80,8 @@ public:
 protected:
     bool centered() const override { return false; }
     void generate(coord_t min_x, coord_t min_y, coord_t max_x, coord_t max_y, const double resolution, InfillPolylineOutput &output) override;
+    void generate(coord_t min_x, coord_t min_y, coord_t max_x, coord_t max_y, const double resolution,
+                              const FillParams &params, InfillPolylineOutput &output) override;
 };
 
 class FillOctagramSpiral : public FillPlanePath

src/libslic3r/Fill/FillRectilinear.cpp

@@ -3576,7 +3576,7 @@ Polylines FillLateralHoneycomb::fill_surface(const Surface *surface, const FillP
     //     |
     //     |
     // 0 --+--
-    //    / \
+    //    ⟋ ⟍
     // why inverted?
     // it makes determining some of the properties easier
     // and the two angled legs provide additional horizontal stiffness

src/libslic3r/Format/STEP.cpp

@@ -712,7 +712,7 @@ unsigned int Step::get_triangle_num(double linear_deflection, double angle_defle
                 return 0;
             }
         }
-    } catch(Exception e) {
+    } catch(const Exception &e) {
         return 0;
     }
     

src/libslic3r/Format/STEP.hpp

@@ -78,7 +78,7 @@ public:
     Standard_Boolean UserBreak() override { return should_stop.load(); }
 
     void Show(const Message_ProgressScope&, const Standard_Boolean) override {
-        std::cout << "Progress: " << GetPosition() << "%" << std::endl;
+        std::cout << "Progress: " << std::fixed << std::setprecision(2) << 100.0 * GetPosition() << "%" << std::endl;
     }
 private:
     std::atomic<bool>& should_stop;

src/libslic3r/GCode.cpp

@@ -13,7 +13,9 @@
 #include "GCode/PrintExtents.hpp"
 #include "GCode/Thumbnails.hpp"
 #include "GCode/WipeTower.hpp"
+#include "GCode/WipeTower2.hpp"
 #include "ShortestPath.hpp"
+#include "GCode/OrderingStrategies.hpp"
 #include "Print.hpp"
 #include "Utils.hpp"
 #include "ClipperUtils.hpp"
@@ -766,30 +768,31 @@ static std::vector<Vec2d> get_path_of_change_filament(const Print& print)
         return changes;
     }
 
+    // Clearance the tower-approach router keeps around the tower: the avoid box is
+    // inflated by this much before routing, and the inflated corners must stay on the
+    // bed for a route to be generated at all.
+    static constexpr float wipe_tower_routing_clearance = 2.f;
+
     // BBS
     // start_pos refers to the last position before the wipe_tower.
     // end_pos refers to the wipe tower's start_pos.
     // using the print coordinate system
-    Polyline WipeTowerIntegration::generate_path_to_wipe_tower(const Point& start_pos,const Point &end_pos , const BoundingBox& avoid_polygon , const BoundingBox& printer_bbx) const
+    Polyline WipeTowerIntegration::generate_path_to_wipe_tower(const Point& start_pos,const Point &end_pos , const BoundingBox& avoid_polygon , const Polygons& bed_polygons) const
     {
         Polyline    res;
-        coord_t         alpha = scaled(2.f); // offset distance
+        coord_t         alpha = scaled(wipe_tower_routing_clearance); // offset distance
         BoundingBox avoid_polygon_inner = avoid_polygon;
         avoid_polygon_inner.offset(alpha);
         coord_t width = avoid_polygon_inner.max[0] - avoid_polygon_inner.min[0];
-        Polygon bed_polygon = printer_bbx.polygon();
         Vec2f v(1, 0);                                                      // the first print direction of end_pos.
         if (abs(end_pos[0] - avoid_polygon_inner.min[0]) < width / 2) v = -v; // judge whether the wipe tower's infill goes to the left or right.
-        // Judge whether the avoid_polygon_inner is outside the printer_bbx.
+        // Judge whether the avoid_polygon_inner is outside the bed. The real printable
+        // outline is tested (not its bounding box), so on circular/custom beds corners
+        // hanging off the bed are rejected.
         // If so, do nothing and just go directly to the end_pos.
-        bool is_bbx_in_bed = true;
         Points avoid_points  = avoid_polygon_inner.polygon().points;
-        for (auto &wipe_tower_bbx_p : avoid_points) {
-            if (ClipperLib::PointInPolygon(wipe_tower_bbx_p, bed_polygon.points) != 1) {
-                is_bbx_in_bed = false;
-                break;
-            }
-        }
+        const bool is_bbx_in_bed = std::all_of(avoid_points.begin(), avoid_points.end(),
+            [&bed_polygons](const Point &pt) { return contains(bed_polygons, pt, /*border_result=*/false); });
         if (!is_bbx_in_bed) {
             res.points.push_back(end_pos);
             return res;
@@ -888,6 +891,77 @@ static std::vector<Vec2d> get_path_of_change_filament(const Print& print)
         return res;
     }
 
+    // Type2 tower-local point -> bed frame. The rib-wall offset is tower-local, so it
+    // rotates with the tower (unlike the BBL tower in append_tcr, which never rotates).
+    Vec2f WipeTowerIntegration::transform_wt2_pt(const Vec2f &pt) const
+    {
+        const float alpha = m_wipe_tower_rotation / 180.f * float(M_PI);
+        return Eigen::Rotation2Df(alpha) * (pt + m_rib_offset) + m_wipe_tower_pos;
+    }
+
+    // Bed outline the tower-approach router plans against, in object coordinates. The real
+    // outline is returned, not its bounding box, so the router's containment tests fail off
+    // the bed on circular/custom shapes; the multi-nozzle narrowing lives in the accessor.
+    Polygons WipeTowerIntegration::shared_printable_area(GCode &gcodegen) const
+    {
+        // The frame change is a pure translation, so transform the origin once.
+        const Point offset = wipe_tower_point_to_object_point(gcodegen, Vec2f(m_plate_origin(0), m_plate_origin(1)));
+        Polygons    bed_polygons = gcodegen.m_print->get_extruder_shared_printable_polygon();
+        for (Polygon &poly : bed_polygons)
+            poly.translate(offset);
+        return bed_polygons;
+    }
+
+    // With skip points enabled the Type2 tower wall has an opening at each toolchange's
+    // entry (tcr.start_pos): route the approach around the tower's bounding box so the
+    // nozzle enters through that opening instead of dragging across the printed wall
+    // (append_tcr parity). Emits only the waypoints leading up to the opening — the
+    // caller still travels to start_wipe_pos itself. Returns an empty string when the
+    // gap wall is off (option off or cone wall) or the approach already starts inside
+    // the tower: such hops never cross the wall and must stay direct.
+    std::string WipeTowerIntegration::travel_to_tower_gap(GCode &gcodegen, const Point &route_start, const Point &start_wipe_pos) const
+    {
+        if (!WipeTower2::use_gap_wall(gcodegen.m_config))
+            return {};
+        const Vec2f plate_origin_2d(m_plate_origin(0), m_plate_origin(1));
+        // Transform tower-local corners exactly like the tcr points; a rotated tower gets a
+        // conservative axis-aligned envelope from the result.
+        auto tower_polygon = [&](const BoundingBoxf &bbx) {
+            Polygon poly = scaled(bbx).polygon();
+            for (Point &p : poly.points)
+                p = wipe_tower_point_to_object_point(gcodegen, transform_wt2_pt(unscale(p).cast<float>()) + plate_origin_2d);
+            return poly;
+        };
+        // The avoid envelope covers the first-layer brim (and rib flare), which a travel may
+        // cross freely: early-out only when the approach already starts over the tower body
+        // itself, so a start between the wall and the brim edge still gets routed in through
+        // the wall opening. Test the rotated polygon, not its bounding box — at angles off the
+        // axes the box's corner triangles cover most of the brim ring.
+        const float body_width = gcodegen.m_config.wipe_tower_wall_type.value == WipeTowerWallType::wtwRib ? m_wipe_tower_depth : m_right;
+        if (tower_polygon(BoundingBoxf(Vec2d(0., 0.), Vec2d(body_width, m_wipe_tower_depth))).contains(route_start))
+            return {};
+
+        const Polygons bed       = shared_printable_area(gcodegen);
+        BoundingBox    avoid_bbx = get_extents(tower_polygon(m_wipe_tower_bbx));
+        // The inflated corners must stay on the bed for the router to generate a route at all:
+        // clamp the box against the bed shrunk by the clearance the router adds, so a tower
+        // parked near the bed edge is still routed along the clamped side instead of always
+        // travelling straight across the tower.
+        BoundingBox clamp_bbx = get_extents(bed);
+        clamp_bbx.offset(-(scaled(wipe_tower_routing_clearance) + SCALED_EPSILON));
+        avoid_bbx.min = avoid_bbx.min.cwiseMax(clamp_bbx.min);
+        avoid_bbx.max = avoid_bbx.max.cwiseMin(clamp_bbx.max);
+        if (avoid_bbx.min.x() >= avoid_bbx.max.x() || avoid_bbx.min.y() >= avoid_bbx.max.y())
+            return {};
+
+        Polyline    travel_polyline = generate_path_to_wipe_tower(route_start, start_wipe_pos, avoid_bbx, bed);
+        std::string gcode;
+        // The polyline's last point is start_wipe_pos itself — emitted by the caller.
+        for (size_t i = 0; i + 1 < travel_polyline.points.size(); ++i)
+            gcode += gcodegen.travel_to(travel_polyline.points[i], erMixed, "Travel to a Wipe Tower");
+        return gcode;
+    }
+
     std::string WipeTowerIntegration::append_tcr(GCode& gcodegen, const WipeTower::ToolChangeResult& tcr, int new_filament_id, double z) const
     {
         if (new_filament_id != -1 && new_filament_id != tcr.new_tool)
@@ -998,6 +1072,7 @@ static std::vector<Vec2d> get_path_of_change_filament(const Print& print)
         std::string change_filament_gcode = gcodegen.config().change_filament_gcode.value;
 
         bool is_used_travel_avoid_perimeter = gcodegen.m_config.prime_tower_skip_points.value;
+        if (is_nozzle_change && !tcr.nozzle_change_result.is_extruder_change) is_used_travel_avoid_perimeter = false;
 
         // add nozzle change gcode into change filament gcode
         std::string nozzle_change_gcode_trans;
@@ -1075,8 +1150,8 @@ static std::vector<Vec2d> get_path_of_change_filament(const Print& print)
 
                 float old_retract_length = (old_filament_id != -1) ? full_config.retraction_length.get_at(old_fi) : 0;
                 float new_retract_length = full_config.retraction_length.get_at(new_fi);
-                float old_retract_length_toolchange = (old_filament_id != -1) ? full_config.retract_length_toolchange.get_at(old_filament_id) : 0;
-                float new_retract_length_toolchange = full_config.retract_length_toolchange.get_at(new_filament_id);
+                float old_retract_length_toolchange = (old_filament_id != -1) ? full_config.retract_length_toolchange.get_at(old_fi) : 0;
+                float new_retract_length_toolchange = full_config.retract_length_toolchange.get_at(new_fi);
                 int old_filament_temp = (old_filament_id != -1) ? (gcodegen.on_first_layer()? full_config.nozzle_temperature_initial_layer.get_at(old_fi) : full_config.nozzle_temperature.get_at(old_fi)) : 210;
                 int new_filament_temp = gcodegen.on_first_layer() ? full_config.nozzle_temperature_initial_layer.get_at(new_fi) : full_config.nozzle_temperature.get_at(new_fi);
                 Vec3d nozzle_pos = gcode_writer.get_position();
@@ -1260,24 +1335,7 @@ static std::vector<Vec2d> get_path_of_change_filament(const Print& print)
                 Vec2f       gcode_last_pos2d{gcode_last_pos[0], gcode_last_pos[1]};
                 Point       gcode_last_pos2d_object = gcodegen.gcode_to_point(gcode_last_pos2d.cast<double>() + plate_origin_2d.cast<double>());
                 Point       start_wipe_pos          = wipe_tower_point_to_object_point(gcodegen, tool_change_start_pos + plate_origin_2d);
-                BoundingBox avoid_bbx, printer_bbx;
-                {
-                    // set printer_bbx
-                    // Multi-nozzle: clamp the avoid-perimeter travel bounds to the region every
-                    // extruder can reach (get_extruder_shared_printable_polygon) instead of the full
-                    // bed. Gated on the multi-nozzle predicate so H2D and every existing single/dual
-                    // printer keep the historic full-printable_area routing byte-identical.
-                    if (is_multi_nozzle_printer(gcodegen.m_config)) {
-                        printer_bbx     = get_extents(gcodegen.m_print->get_extruder_shared_printable_polygon());
-                        printer_bbx.min = wipe_tower_point_to_object_point(gcodegen, unscaled<float>(printer_bbx.min) + plate_origin_2d);
-                        printer_bbx.max = wipe_tower_point_to_object_point(gcodegen, unscaled<float>(printer_bbx.max) + plate_origin_2d);
-                    } else {
-                        Pointfs bed_pointsf = gcodegen.m_config.printable_area.values;
-                        Points  bed_points;
-                        for (auto p : bed_pointsf) { bed_points.push_back(wipe_tower_point_to_object_point(gcodegen, p.cast<float>() + plate_origin_2d)); }
-                        printer_bbx = BoundingBox(bed_points);
-                    }
-                }
+                BoundingBox avoid_bbx;
                 {
                     // set avoid_bbx
                     avoid_bbx            = scaled(m_wipe_tower_bbx);
@@ -1289,7 +1347,7 @@ static std::vector<Vec2d> get_path_of_change_filament(const Print& print)
                     avoid_bbx = BoundingBox(avoid_points.points);
                 }
                 std::string travel_to_wipe_tower_gcode;
-                Polyline    travel_polyline = generate_path_to_wipe_tower(gcode_last_pos2d_object, start_wipe_pos, avoid_bbx, printer_bbx);
+                Polyline    travel_polyline = generate_path_to_wipe_tower(gcode_last_pos2d_object, start_wipe_pos, avoid_bbx, shared_printable_area(gcodegen));
 
                 for (size_t i = 0; i < travel_polyline.points.size(); ++i) {
                     const auto &p = travel_polyline.points[i];
@@ -1307,20 +1365,23 @@ static std::vector<Vec2d> get_path_of_change_filament(const Print& print)
         }
 
         // do unretract after setting current extruder_id
-        // PETG filaments on a device with a filament switcher get a small (2 mm) pre-extrusion
-        // before the tool change. has_filament_switcher is a develop-only key read defensively from the
-        // full config (Orca does not carry it as a static PrintConfig member — same convention as
-        // enable_filament_dynamic_map); no shipping profile sets it (grep resources/profiles = 0), so
-        // is_petg_pre_extrusion is always false -> extra_unretract stays 0 -> byte-identical to the plain
-        // unretract() fleet-wide. The tower-interface contact pre-extrusion length (the
-        // is_contact_pre_extrusion branch) is NOT applied here; it is only computed as the guard used to
-        // give the contact path priority over PETG.
+        // BBS pattern: the wipe tower shifts the toolchange start position outward for the
+        // tower-interface (contact) pre-extrusion and for the PETG-with-filament-switcher case;
+        // the pre-extrusion material itself is laid down here as extra unretract on the approach.
+        // has_filament_switcher is a develop-only key read defensively from the full config (Orca
+        // does not carry it as a static PrintConfig member — same convention as
+        // enable_filament_dynamic_map); no shipping profile sets it, so is_petg_pre_extrusion is
+        // always false fleet-wide.
         const ConfigOptionBool* has_filament_switcher_opt = gcodegen.m_print->full_print_config().option<ConfigOptionBool>("has_filament_switcher");
         bool is_contact_pre_extrusion = tcr.is_contact && gcodegen.m_config.enable_tower_interface_features;
         bool is_petg_pre_extrusion    = !is_contact_pre_extrusion
                                         && gcodegen.config().filament_type.get_at(tcr.new_tool) == "PETG"
                                         && has_filament_switcher_opt && has_filament_switcher_opt->value;
-        float extra_unretract = is_petg_pre_extrusion ? 2.f : 0.f;
+        float extra_unretract = 0.f;
+        if (is_contact_pre_extrusion)
+            extra_unretract = gcodegen.m_config.filament_tower_interface_pre_extrusion_length.get_at(tcr.new_tool);
+        else if (is_petg_pre_extrusion)
+            extra_unretract = 2.f;
         std::string toolchange_unretract_str = (extra_unretract > 0.f) ? gcodegen.unretract(extra_unretract) : gcodegen.unretract();
         check_add_eol(toolchange_unretract_str);
 
@@ -1418,20 +1479,16 @@ static std::vector<Vec2d> get_path_of_change_filament(const Print& print)
         // We want to rotate and shift all extrusions (gcode postprocessing) and starting and ending position
         float alpha = m_wipe_tower_rotation / 180.f * float(M_PI);
 
-        auto transform_wt_pt = [&alpha, this](const Vec2f &pt) -> Vec2f {
-            Vec2f out = Eigen::Rotation2Df(alpha) * pt;
-            out += m_wipe_tower_pos;
-            return out;
-        };
-
+        // Priming lines are absolute bed moves; everything else is tower-local
+        // (transform_wt2_pt).
         Vec2f start_pos = tcr.start_pos;
         Vec2f end_pos   = tcr.end_pos;
         if (!tcr.priming) {
-            start_pos = transform_wt_pt(start_pos);
-            end_pos   = transform_wt_pt(end_pos);
+            start_pos = transform_wt2_pt(start_pos);
+            end_pos   = transform_wt2_pt(end_pos);
         }
 
-        Vec2f wipe_tower_offset   = tcr.priming ? Vec2f::Zero() : m_wipe_tower_pos;
+        Vec2f wipe_tower_offset   = tcr.priming ? Vec2f::Zero() : Vec2f(m_wipe_tower_pos + Eigen::Rotation2Df(alpha) * m_rib_offset);
         float wipe_tower_rotation = tcr.priming ? 0.f : alpha;
         Vec2f plate_origin_2d(m_plate_origin(0), m_plate_origin(1));
 
@@ -1461,16 +1518,34 @@ static std::vector<Vec2d> get_path_of_change_filament(const Print& print)
                                                              || is_ramming
                                                              || tool_change_on_wipe_tower);
 
-        if (should_travel_to_tower || gcodegen.m_need_change_layer_lift_z) {
+        const Point start_wipe_pos     = wipe_tower_point_to_object_point(gcodegen, start_pos + plate_origin_2d);
+        const bool travel_to_tower_now = should_travel_to_tower || gcodegen.m_need_change_layer_lift_z;
+        if (travel_to_tower_now) {
             // FIXME: It would be better if the wipe tower set the force_travel flag for all toolchanges,
             // then we could simplify the condition and make it more readable.
-            gcode += gcodegen.retract();
+
+            // Orca: pass the configured lift type, as append_tcr does above. lazy_lift() keeps
+            // the first type it is given, so the NormalLift default would pin this hop to a
+            // standing move. Slope and spiral both need a known head position.
+            LiftType lift_type = LiftType::NormalLift;
+            if (gcodegen.writer().filament() != nullptr && gcodegen.writer().is_current_position_clear()) {
+                ZHopType z_hop_type = ZHopType(gcodegen.config().z_hop_types.get_at(
+                    gcodegen.get_filament_config_index((int) gcodegen.writer().filament()->id())));
+                if (z_hop_type == ZHopType::zhtAuto)
+                    z_hop_type = ZHopType::zhtSpiral;
+                lift_type = gcodegen.to_lift_type(z_hop_type);
+            }
+            gcode += gcodegen.retract(false, false, lift_type);
             gcodegen.m_avoid_crossing_perimeters.use_external_mp_once();
-            gcode += gcodegen.travel_to(wipe_tower_point_to_object_point(gcodegen, start_pos + plate_origin_2d), erMixed, "Travel to a Wipe Tower");
+            if (!tcr.priming && gcodegen.last_pos_defined())
+                gcode += travel_to_tower_gap(gcodegen, gcodegen.last_pos(), start_wipe_pos);
+            gcode += gcodegen.travel_to(start_wipe_pos, erMixed, "Travel to a Wipe Tower");
             gcode += gcodegen.unretract();
         } else {
             // When this is multiextruder printer without any ramming, we can just change
-            // the tool without travelling to the tower.
+            // the tool without travelling to the tower. The tower entry travel then lives
+            // inside the tcr gcode; with skip points on it is rerouted below, once the
+            // toolchange gcode (and the head position it ends at) is known.
         }
 
         if (will_go_down) {
@@ -1492,7 +1567,38 @@ static std::vector<Vec2d> get_path_of_change_filament(const Print& print)
                     interface_temp = gcodegen.config().nozzle_temperature_range_high.get_at(new_extruder_id);
                 toolchange_temp_override = interface_temp;
             }
-            toolchange_gcode_str = gcodegen.set_extruder(new_extruder_id, tcr.print_z, false, toolchange_temp_override); // TODO: toolchange_z vs print_z
+            toolchange_gcode_str = gcodegen.set_extruder(new_extruder_id, tcr.print_z, false, toolchange_temp_override,
+                                                         WipeTower2::wait_for_temp_enabled(gcodegen.m_config)); // TODO: toolchange_z vs print_z
+            if (!travel_to_tower_now && !tcr.priming && WipeTower2::use_gap_wall(gcodegen.m_config)) {
+                // The tool changed in place (multi-tool printer without ramming), so the
+                // tower entry is the tcr's own positioning move — a straight line across
+                // the printed wall. Route it around the tower and in through the wall
+                // opening instead, riding at the end of the change_filament_gcode
+                // substitution so the generator's positioning move degrades to a
+                // zero-length one (append_tcr parity: travel after the filament change,
+                // retracted, with the new filament).
+                Vec3f last_gcode_pos = gcodegen.writer().get_position().cast<float>();
+                Point route_start;
+                bool  have_start = false;
+                if (GCodeProcessor::get_last_position_from_gcode(toolchange_gcode_str, last_gcode_pos)) {
+                    // A custom change_filament_gcode may have moved the head (tool docks
+                    // etc.); recover the real position from the emitted gcode.
+                    route_start = gcodegen.gcode_to_point(Vec2d(last_gcode_pos.x(), last_gcode_pos.y()) + plate_origin_2d.cast<double>());
+                    have_start  = true;
+                } else if (gcodegen.last_pos_defined()) {
+                    route_start = gcodegen.last_pos();
+                    have_start  = true;
+                }
+                if (have_start) {
+                    gcodegen.set_last_pos(route_start);
+                    gcodegen.m_avoid_crossing_perimeters.use_external_mp_once();
+                    std::string travel = travel_to_tower_gap(gcodegen, route_start, start_wipe_pos);
+                    travel += gcodegen.travel_to(start_wipe_pos, erMixed, "Travel to a Wipe Tower");
+                    check_add_eol(travel);
+                    toolchange_gcode_str += travel;
+                    gcodegen.set_last_pos(start_wipe_pos);
+                }
+            }
             if (gcodegen.config().enable_prime_tower) {
                 deretraction_str += gcodegen.writer().travel_to_z(z, "Force restore layer Z", true);
                 Vec3d position{gcodegen.writer().get_position()};
@@ -1613,7 +1719,7 @@ static std::vector<Vec2d> get_path_of_change_filament(const Print& print)
                 std::string trimmed = line;
                 trimmed.erase(0, trimmed.find_first_not_of(" \t"));
                 bool skip_line = false;
-                if (boost::starts_with(trimmed, "M109")) {
+                if (boost::starts_with(trimmed, "M109") && trimmed.find(WipeTower2::wait_for_temp_tag()) == std::string::npos) {
                     bool matches_extruder = true;
                     if (trimmed.find('T') != std::string::npos)
                         matches_extruder = trimmed.find(t_token) != std::string::npos;
@@ -1678,7 +1784,7 @@ static std::vector<Vec2d> get_path_of_change_filament(const Print& print)
             // Prepare a future wipe.
             gcodegen.m_wipe.reset_path();
             for (const Vec2f& wipe_pt : tcr.wipe_path)
-                gcodegen.m_wipe.path.points.emplace_back(wipe_tower_point_to_object_point(gcodegen, transform_wt_pt(wipe_pt) + plate_origin_2d));
+                gcodegen.m_wipe.path.points.emplace_back(wipe_tower_point_to_object_point(gcodegen, transform_wt2_pt(wipe_pt) + plate_origin_2d));
         }
 
         // Let the planner know we are traveling between objects.
@@ -2792,6 +2898,7 @@ void GCode::_do_export(Print& print, GCodeOutputStream &file, ThumbnailsGenerato
     DoExport::init_gcode_processor(print.config(), m_processor, m_silent_time_estimator_enabled,
                                    print.get_layered_nozzle_group_result());
     const bool is_bbl_printers = print.is_BBL_printer();
+    const bool skip_config_block = print.config().gcode_skip_config_block;
     const WipeTowerType wipe_tower_type = print.wipe_tower_type();
     m_calib_config.clear();
     // resets analyzer's tracking data
@@ -2804,6 +2911,7 @@ void GCode::_do_export(Print& print, GCodeOutputStream &file, ThumbnailsGenerato
     m_role_based_fan_marker_layer.fill(-1);
 
     m_fan_mover.release();
+    m_ordering_cache.clear();
     
     m_writer.set_is_bbl_machine(is_bbl_printers);
 
@@ -2966,7 +3074,7 @@ void GCode::_do_export(Print& print, GCodeOutputStream &file, ThumbnailsGenerato
       // as configuration key / value pairs to be parsable by older versions of
       // PrusaSlicer G-code viewer.
     {
-        if (is_bbl_printers) {
+        if (is_bbl_printers && !skip_config_block) {
             file.write("; CONFIG_BLOCK_START\n");
             std::string full_config;
             append_full_config(print, full_config);
@@ -3124,11 +3232,20 @@ void GCode::_do_export(Print& print, GCodeOutputStream &file, ThumbnailsGenerato
         // In non-sequential print, the printing extruders may have been modified by the extruder switches stored in Model::custom_gcode_per_print_z.
         // Therefore initialize the printing extruders from there.
         this->set_extruders(tool_ordering.all_extruders());
-        print_object_instances_ordering = 
-            // By default, order object instances using a nearest neighbor search.
-            print.config().print_order == PrintOrder::Default ? chain_print_object_instances(print)
+        print_object_instances_ordering =
+            // By default, order object instances using nearest-neighbor chaining plus
+            // 2-opt and crossing-removal post-processing.
+            (print.config().print_order == PrintOrder::Default ? chain_print_object_instances(print)
+            // Snake: serpentine row traversal + 2-opt
+            : (print.config().print_order == PrintOrder::Snake ? chain_print_object_instances_snake(print)
+            // Best of all: run every strategy, pick the shortest total path
+            : (print.config().print_order == PrintOrder::BestOfStrategies ? chain_print_object_instances_best_of(print)
             // Otherwise same order as the object list
-            : sort_object_instances_by_model_order(print);
+            : sort_object_instances_by_model_order(print))));
+
+
+
+
     }
     if (initial_extruder_id == (unsigned int)-1) {
         // Nothing to print!
@@ -3984,23 +4101,25 @@ void GCode::_do_export(Print& print, GCodeOutputStream &file, ThumbnailsGenerato
                 GCodeProcessor::ETags::Estimated_Printing_Time_Placeholder)
             .c_str());
       file.write("\n");
-      file.write("; CONFIG_BLOCK_START\n");
-      std::string full_config;
-      append_full_config(print, full_config);
-      if (!full_config.empty())
-        file.write(full_config);
+      if (!skip_config_block) {
+          file.write("; CONFIG_BLOCK_START\n");
+          std::string full_config;
+          append_full_config(print, full_config);
+          if (!full_config.empty())
+            file.write(full_config);
 
-      // SoftFever: write compatiple info
-      int first_layer_bed_temperature = get_bed_temperature(0, true, print.config().curr_bed_type);
-      file.write_format("; first_layer_bed_temperature = %d\n", first_layer_bed_temperature);
-      file.write_format("; bed_shape = %s\n", print.full_print_config().opt_serialize("printable_area").c_str());
-      file.write_format("; first_layer_temperature = %d\n", print.config().nozzle_temperature_initial_layer.get_at(0));
-      file.write_format("; first_layer_height = %.3f\n", print.config().initial_layer_print_height.value);
-        
-        //SF TODO
-//      file.write_format("; variable_layer_height = %d\n", print.ad.adaptive_layer_height ? 1 : 0);
-   
-      file.write("; CONFIG_BLOCK_END\n\n");
+          // SoftFever: write compatiple info
+          int first_layer_bed_temperature = get_bed_temperature(0, true, print.config().curr_bed_type);
+          file.write_format("; first_layer_bed_temperature = %d\n", first_layer_bed_temperature);
+          file.write_format("; bed_shape = %s\n", print.full_print_config().opt_serialize("printable_area").c_str());
+          file.write_format("; first_layer_temperature = %d\n", print.config().nozzle_temperature_initial_layer.get_at(0));
+          file.write_format("; first_layer_height = %.3f\n", print.config().initial_layer_print_height.value);
+
+            //SF TODO
+//          file.write_format("; variable_layer_height = %d\n", print.ad.adaptive_layer_height ? 1 : 0);
+
+          file.write("; CONFIG_BLOCK_END\n\n");
+      } // !skip_config_block
 
     }
     file.write("\n");
@@ -5406,7 +5525,7 @@ LayerResult GCode::process_layer(
     // add tag for processor
     gcode += ";" + GCodeProcessor::reserved_tag(GCodeProcessor::ETags::Layer_Change) + "\n";
     // export layer z
-    char buf[64];
+    char buf[80];
     sprintf(buf, print.is_BBL_printer() ? "; Z_HEIGHT: %g\n" : ";Z:%g\n", print_z);
     gcode += buf;
     // export layer height
@@ -5519,7 +5638,9 @@ LayerResult GCode::process_layer(
     //Calibration Layer-specific GCode
     switch (print.calib_mode()) {
         case CalibMode::Calib_PA_Tower: {
-            gcode += writer().set_pressure_advance(print.calib_params().start + static_cast<int>(print_z) * print.calib_params().step);
+            gcode += writer().set_pressure_advance(this->interpolate_value_across_layers(static_cast<float>(print.calib_params().start),
+                                                                                         static_cast<float>(print.calib_params().end),
+                                                                                         static_cast<float>(print.calib_params().step)));
             break;
         }
         case CalibMode::Calib_Temp_Tower: {
@@ -5527,7 +5648,12 @@ LayerResult GCode::process_layer(
             break;
         }
         case CalibMode::Calib_VFA_Tower: {
-            auto _speed = print.calib_params().start + std::floor(print_z / 5.0) * print.calib_params().step;
+            // Step the outer wall speed from start to end across the tower's layers. Plater::calib_VFA sizes the
+            // geometry so each speed step spans one visual block (a fixed number of layers), so the layer-based
+            // stepping stays aligned with the blocks regardless of nozzle size / layer height.
+            float _speed = this->interpolate_value_across_layers(static_cast<float>(print.calib_params().start),
+                                                                 static_cast<float>(print.calib_params().end),
+                                                                 static_cast<float>(print.calib_params().step));
             m_calib_config.set_key_value("outer_wall_speed", new ConfigOptionFloatsNullable({std::round(_speed)}));
             break;
         }
@@ -5681,10 +5807,17 @@ LayerResult GCode::process_layer(
     for (const auto &layer_to_print : layers) {
         if (layer_to_print.object_layer) {
             const auto& regions = layer_to_print.object_layer->regions();
-            const bool  enable_overhang_speed = std::any_of(regions.begin(), regions.end(), [this](const LayerRegion* r) {
+            const bool has_extrusions = std::any_of(regions.begin(), regions.end(), [](const LayerRegion* r) {
+                return r->has_extrusions();
+            });
+            const bool enable_overhang_speed = std::any_of(regions.begin(), regions.end(), [this](const LayerRegion* r) {
                 return r->has_extrusions() && r->region().config().enable_overhang_speed.get_at(get_nozzle_config_index(m_writer.filament()->id()));
             });
-            if (enable_overhang_speed) {
+            const bool enable_overhang_fan = m_enable_cooling_markers && has_extrusions &&
+                std::any_of(m_config.enable_overhang_bridge_fan.values.begin(),
+                            m_config.enable_overhang_bridge_fan.values.end(),
+                            [](unsigned char value) { return value != 0; });
+            if (enable_overhang_speed || enable_overhang_fan) {
                 m_extrusion_quality_estimator.prepare_for_new_layer(layer_to_print.original_object,
                                                                     layer_to_print.object_layer);
             }
@@ -5952,41 +6085,128 @@ LayerResult GCode::process_layer(
     if (m_farthest_point_timelapse.enabled)
         compute_farthest_point(layers, most_used_extruder, support_filaments);
 
-    std::map<unsigned int, std::vector<InstanceToPrint>> filament_to_print_instances;
+    // Per filament: instances to print, and the visit sequence over them. Island-level ordering
+    // may visit an instance more than once per layer; otherwise one visit per instance.
+    std::map<unsigned int, std::pair<std::vector<InstanceToPrint>, std::vector<InstanceVisit>>> filament_to_print_instances;
     {
+        // Order individual islands rather than whole instances. Off for by-object sequencing,
+        // sequential printing, and the explicit AsObjectList order, which tour whole instances.
+        const bool island_level_ordering = print.config().print_sequence != PrintSequence::ByObject &&
+            single_object_instance_idx == size_t(-1) &&
+            print.config().print_order != PrintOrder::AsObjectList;
         for (unsigned int filament_id : layer_tools.extruders) {
             auto objects_by_extruder_it = by_extruder.find(filament_id);
             if (objects_by_extruder_it == by_extruder.end()) continue;
 
+            auto &filament_plan = filament_to_print_instances[filament_id];
+
+            if (!island_level_ordering) {
+                // One visit per instance, printing all of its islands.
+                filament_plan.first = sort_print_object_instances(objects_by_extruder_it->second, layers, ordering, single_object_instance_idx);
+                filament_plan.second.reserve(filament_plan.first.size());
+                for (size_t i = 0; i < filament_plan.first.size(); ++i)
+                    filament_plan.second.push_back({i, {}, true});
+                continue;
+            }
+
             int   plate_idx = print.get_plate_index();
             Point wt_pos(print.config().wipe_tower_x.get_at(plate_idx), print.config().wipe_tower_y.get_at(plate_idx));
 
+            // Build the instances and one tour node per non-empty island (a single node for
+            // instances without chainable islands). Positions quantized to 1 mm so small
+            // centroid drift between layers still hits the tour cache below.
             std::vector<GCode::ObjectByExtruder> &objects_by_extruder = objects_by_extruder_it->second;
-            std::vector<const PrintObject *>      print_objects;
-            for (int obj_idx = 0; obj_idx < objects_by_extruder.size(); obj_idx++) {
-                auto &object_by_extruder = objects_by_extruder[obj_idx];
+            std::vector<InstanceToPrint> &instances = filament_plan.first;
+            std::vector<IslandOrderNode> nodes;
+            std::vector<size_t>          node_instances;
+            auto quantize_to_mm = [](const Point &pt) -> Point {
+                const coord_t grid = coord_t(scale_(1.));
+                // Round to the nearest 1 mm symmetrically (integer division truncates toward
+                // zero, which would make the bucket straddling the origin twice as wide).
+                auto q = [grid](coord_t v) -> coord_t {
+                    return ((v >= 0 ? v + grid / 2 : v - grid / 2) / grid) * grid;
+                };
+                return Point(q(pt.x()), q(pt.y()));
+            };
+            for (ObjectByExtruder &object_by_extruder : objects_by_extruder) {
                 if (object_by_extruder.islands.empty() && (object_by_extruder.support == nullptr || object_by_extruder.support->empty())) continue;
 
-                print_objects.push_back(print.get_object(obj_idx));
+                const size_t       layer_id     = &object_by_extruder - objects_by_extruder.data();
+                const PrintObject *print_object = layers[layer_id].original_object;
+                if (print_object == nullptr)
+                    continue;
+                const Layer *obj_layer = layers[layer_id].object_layer;
+                std::vector<ObjectByExtruder::Island> &islands = object_by_extruder.islands;
+                const bool islands_chainable = obj_layer != nullptr && islands.size() == obj_layer->lslices.size() + 1;
+                for (size_t instance_id = 0; instance_id < print_object->instances().size(); ++instance_id) {
+                    const size_t instance_idx = instances.size();
+                    instances.emplace_back(object_by_extruder, layer_id, *print_object, instance_id,
+                                           print_object->instances()[instance_id].model_instance->get_labeled_id());
+                    const Point &shift = print_object->instances()[instance_id].shift;
+                    const size_t first_node = nodes.size();
+                    if (islands_chainable)
+                        for (size_t i = 0; i + 1 < islands.size(); ++i)
+                            if (!islands[i].by_region.empty()) {
+                                nodes.push_back({print_object->id(), instance_id, i,
+                                                 quantize_to_mm(obj_layer->lslices[i].contour.centroid() + shift)});
+                                node_instances.emplace_back(instance_idx);
+                            }
+                    if (nodes.size() == first_node) {
+                        // No chainable islands: tour the whole instance as one stop.
+                        nodes.push_back({print_object->id(), instance_id, size_t(-1), quantize_to_mm(shift)});
+                        node_instances.emplace_back(instance_idx);
+                    }
+                }
             }
 
-            std::vector<const PrintInstance *> new_ordering = chain_print_object_instances(print_objects, &wt_pos);
-            std::reverse(new_ordering.begin(), new_ordering.end());
+            // Reuse the cached tour while this filament's island layout is unchanged.
+            auto &cache_entry = m_ordering_cache[filament_id];
+            if (!(cache_entry.first == nodes)) {
+                cache_entry.first = nodes;
+                Points node_points;
+                node_points.reserve(nodes.size());
+                for (const IslandOrderNode &node : nodes)
+                    node_points.emplace_back(node.pos);
+                std::vector<size_t> tour = order_points_with_strategy(node_points, print.config().print_order, &wt_pos);
+                // Chained starting near the wipe tower, reversed so the layer ends near it.
+                std::reverse(tour.begin(), tour.end());
 
-            if (print.config().print_sequence == PrintSequence::ByObject) {
-                filament_to_print_instances[filament_id] = sort_print_object_instances(objects_by_extruder_it->second, layers, ordering, single_object_instance_idx);
-            } else {
-                
-                // PrintSequence::ByLayer to use global ordering ( per object ordering ) if intra-layer order PrintOrder::AsObjectList is specified while keeping behaviour of PrintSequence::ByLayer
-                const std::vector<const PrintInstance*>* ordering_for_filament = (print.config().print_order == PrintOrder::AsObjectList && ordering != nullptr) ? ordering: &new_ordering;
-                filament_to_print_instances[filament_id] = sort_print_object_instances(objects_by_extruder_it->second, layers, ordering_for_filament, single_object_instance_idx);
+                // Group consecutive tour stops of the same instance into visits.
+                std::vector<InstanceVisit> visits;
+                std::vector<bool> instance_seen(instances.size(), false);
+                std::vector<int>  last_visit_of_instance(instances.size(), -1);
+                for (size_t node_idx : tour) {
+                    const size_t instance_idx = node_instances[node_idx];
+                    if (visits.empty() || visits.back().instance_idx != instance_idx) {
+                        visits.push_back({instance_idx, {}, !instance_seen[instance_idx]});
+                        instance_seen[instance_idx] = true;
+                    }
+                    if (nodes[node_idx].island_idx != size_t(-1))
+                        visits.back().islands.emplace_back(nodes[node_idx].island_idx);
+                    last_visit_of_instance[instance_idx] = int(visits.size()) - 1;
+                }
+                // The trailing catch-all island has no geometry to chain by; append it to the
+                // instance's last visit.
+                for (size_t i = 0; i < instances.size(); ++i) {
+                    if (last_visit_of_instance[i] < 0)
+                        continue;
+                    InstanceVisit &last_visit = visits[size_t(last_visit_of_instance[i])];
+                    if (last_visit.islands.empty())
+                        // A visit without explicit islands already prints everything.
+                        continue;
+                    std::vector<ObjectByExtruder::Island> &islands = instances[i].object_by_extruder.islands;
+                    if (!islands.back().by_region.empty())
+                        last_visit.islands.emplace_back(islands.size() - 1);
+                }
+                cache_entry.second = std::move(visits);
             }
+            filament_plan.second = cache_entry.second;
         }
     }
 
     std::set<size_t> layer_object_label_ids;
     for (auto iter = filament_to_print_instances.begin(); iter != filament_to_print_instances.end(); ++iter) {
-        for (const InstanceToPrint &instance : iter->second) {
+        for (const InstanceToPrint &instance : iter->second.first) {
             layer_object_label_ids.insert(instance.label_object_id);
         }
     }
@@ -6056,7 +6276,7 @@ LayerResult GCode::process_layer(
 
         if (print.config().print_sequence == PrintSequence::ByLayer && m_enable_exclude_object && print.config().support_object_skip_flush.value) {
             std::vector<size_t> filament_instances_id;
-            for (InstanceToPrint &instance : filament_to_print_instances[extruder_id]) filament_instances_id.emplace_back(instance.label_object_id);
+            for (InstanceToPrint &instance : filament_to_print_instances[extruder_id].first) filament_instances_id.emplace_back(instance.label_object_id);
             m_filament_instances_code = _encode_label_ids_to_base64(filament_instances_id);
         }
 
@@ -6137,7 +6357,9 @@ LayerResult GCode::process_layer(
         if (layer_tools.has_wipe_tower && m_wipe_tower)
             m_last_processor_extrusion_role = erWipeTower;
 
-        std::vector<InstanceToPrint> &instances_to_print = filament_to_print_instances[extruder_id];
+        auto &filament_plan = filament_to_print_instances[extruder_id];
+        std::vector<InstanceToPrint>     &instances_to_print = filament_plan.first;
+        const std::vector<InstanceVisit> &instance_visits    = filament_plan.second;
 
         // We are almost ready to print. However, we must go through all the objects twice to print the overridden extrusions first (infill/perimeter wiping feature):
         std::vector<ObjectByExtruder::Island::Region> by_region_per_copy_cache;
@@ -6145,10 +6367,11 @@ LayerResult GCode::process_layer(
             if (is_anything_overridden && print_wipe_extrusions == 0)
                 gcode+="; PURGING FINISHED\n";
 
-            for (InstanceToPrint &instance_to_print : instances_to_print) {
+            for (const InstanceVisit &visit : instance_visits) {
+                InstanceToPrint &instance_to_print = instances_to_print[visit.instance_idx];
                 const auto& inst = instance_to_print.print_object.instances()[instance_to_print.instance_id];
                 const LayerToPrint &layer_to_print = layers[instance_to_print.layer_id];
-                if (print_wipe_extrusions == (is_anything_overridden ? 1 : 0)) {
+                if (visit.first_visit && print_wipe_extrusions == (is_anything_overridden ? 1 : 0)) {
                     gcode += generate_object_skirt_group(print, instance_to_print.print_object, instance_to_print.instance_id, layer_tools, layer, extruder_id);
                     gcode += generate_object_brim(print, instance_to_print.print_object, instance_to_print.instance_id, first_layer);
                 }
@@ -6201,7 +6424,7 @@ LayerResult GCode::process_layer(
                     m_avoid_crossing_perimeters.use_external_mp_once();
                 m_last_obj_copy = this_object_copy;
                 this->set_origin(unscale(offset));
-                if (instance_to_print.object_by_extruder.support != nullptr) {
+                if (visit.first_visit && instance_to_print.object_by_extruder.support != nullptr) {
                     m_layer = layers[instance_to_print.layer_id].support_layer;
                     m_object_layer_over_raft = false;
 
@@ -6235,9 +6458,42 @@ LayerResult GCode::process_layer(
                     m_layer = layer_to_print.layer();
                     m_object_layer_over_raft = object_layer_over_raft;
                 }
-                //FIXME order islands?
                 // Sequential tool path ordering of multiple parts within the same object, aka. perimeter tracking (#5511)
-                for (ObjectByExtruder::Island &island : instance_to_print.object_by_extruder.islands) {
+                // Island print order. Use the islands the tour assigned to this visit; if none,
+                // chain all islands nearest-neighbor from the current nozzle position (last_pos(),
+                // in this instance's frame after set_origin() above). Empty islands are skipped;
+                // the trailing catch-all island has no centroid to chain by and always goes last.
+                std::vector<ObjectByExtruder::Island> &islands = instance_to_print.object_by_extruder.islands;
+                std::vector<size_t> island_order = visit.islands;
+                if (island_order.empty()) {
+                    island_order.reserve(islands.size());
+                    if (layer_to_print.object_layer != nullptr && islands.size() == layer_to_print.object_layer->lslices.size() + 1) {
+                        for (size_t i = 0; i + 1 < islands.size(); ++i)
+                            if (!islands[i].by_region.empty())
+                                island_order.emplace_back(i);
+                        if (island_order.size() > 1) {
+                            Points island_centroids;
+                            island_centroids.reserve(island_order.size());
+                            for (size_t i : island_order)
+                                island_centroids.emplace_back(layer_to_print.object_layer->lslices[i].contour.centroid());
+                            const Point start_near = this->last_pos();
+                            std::vector<size_t> chain = chain_points(island_centroids, this->last_pos_defined() ? &start_near : nullptr);
+                            std::vector<size_t> ordered;
+                            ordered.reserve(island_order.size());
+                            for (size_t k : chain)
+                                ordered.emplace_back(island_order[k]);
+                            island_order = std::move(ordered);
+                        }
+                        if (!islands.back().by_region.empty())
+                            island_order.emplace_back(islands.size() - 1);
+                    } else {
+                        // Unexpected islands layout, keep the stored order.
+                        for (size_t i = 0; i < islands.size(); ++i)
+                            island_order.emplace_back(i);
+                    }
+                }
+                for (size_t island_idx : island_order) {
+                    ObjectByExtruder::Island &island = islands[island_idx];
                     const auto& by_region_specific = is_anything_overridden ? island.by_region_per_copy(by_region_per_copy_cache, static_cast<unsigned int>(instance_to_print.instance_id), extruder_id, print_wipe_extrusions != 0) : island.by_region;
                     // When starting a new object, use the external motion planner for the first travel move.
                     const Point& offset = instance_to_print.print_object.instances()[instance_to_print.instance_id].shift;
@@ -7394,8 +7650,7 @@ std::string GCode::_extrude(const ExtrusionPath &path, std::string description,
             if (sloped) {
                 speed = std::min(speed, m_config.scarf_joint_speed.get_abs_value(speed));
             }
-        } 
-        else if(path.role() == erInternalBridgeInfill) {
+        } else if(path.role() == erInternalBridgeInfill) {
             speed = m_config.get_abs_value_at("internal_bridge_speed", get_nozzle_config_index(m_writer.filament()->id()));
         } else if (path.role() == erOverhangPerimeter || path.role() == erSupportTransition || path.role() == erBridgeInfill) {
             speed = NOZZLE_CONFIG(bridge_speed);
@@ -7406,7 +7661,10 @@ std::string GCode::_extrude(const ExtrusionPath &path, std::string description,
         } else if (path.role() == erTopSolidInfill) {
             speed = NOZZLE_CONFIG(top_surface_speed);
         } else if (path.role() == erIroning) {
-            speed = m_config.get_abs_value("ironing_speed");
+            const size_t filament_idx = get_filament_config_index(m_writer.filament()->id());
+            speed = m_config.filament_ironing_speed.is_nil(filament_idx)
+                ? m_config.get_abs_value("ironing_speed")
+                : m_config.filament_ironing_speed.get_at(filament_idx);
         } else if (path.role() == erBottomSurface) {
             speed = NOZZLE_CONFIG(initial_layer_infill_speed);
         } else if (path.role() == erGapFill) {
@@ -7523,7 +7781,10 @@ std::string GCode::_extrude(const ExtrusionPath &path, std::string description,
     bool variable_speed = false;
     std::vector<ProcessedPoint> new_points {};
 
-    if (NOZZLE_CONFIG(enable_overhang_speed) && !this->on_first_layer() && !object_layer_over_raft() &&
+    const bool need_overhang_detection = NOZZLE_CONFIG(enable_overhang_speed) ||
+        (FILAMENT_CONFIG(enable_overhang_bridge_fan) && m_enable_cooling_markers);
+
+    if (need_overhang_detection && !this->on_first_layer() && !object_layer_over_raft() &&
         (is_bridge(path.role()) || is_perimeter(path.role()))) {
             bool is_external = is_external_perimeter(path.role());
             double ref_speed   = is_external ? NOZZLE_CONFIG(outer_wall_speed) : NOZZLE_CONFIG(inner_wall_speed);
@@ -7582,6 +7843,11 @@ std::string GCode::_extrude(const ExtrusionPath &path, std::string description,
             }
             variable_speed = std::any_of(new_points.begin(), new_points.end(),
                                          [speed](const ProcessedPoint &p) { return fabs(double(p.speed) - speed) > 1; }); // Ignore small speed variations (under 1mm/sec)
+            if (!NOZZLE_CONFIG(enable_overhang_speed) && FILAMENT_CONFIG(enable_overhang_bridge_fan) && m_enable_cooling_markers) {
+                for (ProcessedPoint &point : new_points)
+                    point.speed = speed;
+                variable_speed = new_points.size() > 1;
+            }
     }
 
     double F = speed * 60;  // convert mm/sec to mm/min
@@ -8194,29 +8460,22 @@ std::string GCode::extrusion_role_to_string_for_parser(const ExtrusionRole & rol
 }
 
 // Calculate the interpolated value for the current layer between start_value and end_value.
-// Step will create equal layers steps from first to last value.
+// Step > 0 splits the range into equal-width bands from first to last value (both inclusive).
 // Step = 0 means gradual interpolation finishing at last value.
 float GCode::interpolate_value_across_layers(float start_value, float end_value, float step) const
 {
     if (m_layer_index <= 1) {
         return start_value;
     }
-    else {
-        bool use_steps = step > 0.f;
-        if (use_steps) {
-            if (start_value > end_value) {
-                start_value += step;
-            } else {
-                end_value += step;
-            }
-        }
-        float ratio = m_layer_index / (m_layer_count - 1.f);
-        float value = start_value + ratio * (end_value - start_value);
-        if (use_steps) {
-            value = trunc(value / step) * step;
-        }
-        return value;
+    const float ratio = m_layer_index / (m_layer_count - 1.f);
+    if (step > 0.f) {
+        // Discrete equal-width bands. band is clamped to the last band so the result can't overshoot the range:
+        // at the top layer ratio * n_bands == n_bands, which would otherwise index one band past the end.
+        const int n_bands = std::lround(std::abs(end_value - start_value) / step) + 1;
+        const int band    = std::min(n_bands - 1, static_cast<int>(ratio * n_bands));
+        return start_value + (end_value >= start_value ? 1.f : -1.f) * band * step;
     }
+    return start_value + ratio * (end_value - start_value);
 }
 
 std::string encodeBase64(uint64_t value)
@@ -8696,7 +8955,7 @@ void GCode::update_placeholder_parser_with_variant_params()
     }
 }
 
-std::string GCode::set_extruder(unsigned int new_filament_id, double print_z, bool by_object, int toolchange_temp_override)
+std::string GCode::set_extruder(unsigned int new_filament_id, double print_z, bool by_object, int toolchange_temp_override, bool defer_temp_wait)
 {
     int new_extruder_id = get_extruder_id(new_filament_id);
     if (!m_writer.need_toolchange(new_filament_id))
@@ -8795,7 +9054,7 @@ std::string GCode::set_extruder(unsigned int new_filament_id, double print_z, bo
     // per-layer nozzle grouping; resolve the column instead of indexing by the filament id.
     size_t new_fi = get_filament_config_index((int)new_filament_id);
     float new_retract_length = m_config.retraction_length.get_at(new_fi);
-    float new_retract_length_toolchange = m_config.retract_length_toolchange.get_at(new_filament_id);
+    float new_retract_length_toolchange = m_config.retract_length_toolchange.get_at(new_fi);
     int new_filament_temp = this->on_first_layer() ? m_config.nozzle_temperature_initial_layer.get_at(new_fi) : m_config.nozzle_temperature.get_at(new_fi);
     // BBS: if print_z == 0 use first layer temperature
     if (abs(print_z) < EPSILON)
@@ -8803,6 +9062,24 @@ std::string GCode::set_extruder(unsigned int new_filament_id, double print_z, bo
     if (toolchange_temp_override > 0)
         new_filament_temp = toolchange_temp_override;
 
+    // With wait_for_temp_on_wipe_tower the blocking M109 is deferred to the wipe tower, so raise
+    // the incoming filament's target here — ahead of the tool change rather than after it — and
+    // let the heat-up overlap the change itself as well as the travel to the tower. The command
+    // always carries an explicit tool index (the option is off for single extruder MM, so the
+    // writer emits one), leaving the outgoing filament that pre_toolchange just dropped to its
+    // standby temperature alone. nozzle_temperature == 0 means "use the first layer temperature".
+    if (defer_temp_wait) {
+        // Target what the tower will wait on. It waits on the first layer temperature not only on
+        // the first layer but also while priming, which runs before any layer is set: there
+        // on_first_layer() is false and print_z is the initial layer height, so neither test above
+        // catches it. nozzle_temperature == 0 means "use the first layer temperature" as well.
+        int preheat_temp = new_filament_temp;
+        if (toolchange_temp_override <= 0 && (m_layer == nullptr || preheat_temp <= 0))
+            preheat_temp = m_config.nozzle_temperature_initial_layer.get_at(new_fi);
+        if (preheat_temp > 0)
+            gcode += m_writer.set_temperature(preheat_temp, false, new_filament_id);
+    }
+
     Vec3d nozzle_pos = m_writer.get_position();
     float old_retract_length, old_retract_length_toolchange, wipe_volume;
     int old_filament_temp, old_filament_e_feedrate;
@@ -8826,7 +9103,7 @@ std::string GCode::set_extruder(unsigned int new_filament_id, double print_z, bo
         // gap-filled carry-forward, so its current-layer column matches the nozzle it occupies.
         size_t old_fi = get_filament_config_index(old_filament_id);
         old_retract_length = m_config.retraction_length.get_at(old_fi);
-        old_retract_length_toolchange = m_config.retract_length_toolchange.get_at(old_filament_id);
+        old_retract_length_toolchange = m_config.retract_length_toolchange.get_at(old_fi);
         old_filament_temp = this->on_first_layer()? m_config.nozzle_temperature_initial_layer.get_at(old_fi) : m_config.nozzle_temperature.get_at(old_fi);
 
         //During the filament change, the extruder will extrude an extra length of grab_length for the corresponding detection, so the purge can reduce this length.
@@ -9106,8 +9383,10 @@ std::string GCode::set_extruder(unsigned int new_filament_id, double print_z, bo
         }
         check_add_eol(gcode);
     }
-    // Set the new extruder to the operating temperature.
-    if (m_ooze_prevention.enable)
+    // Set the new extruder to the operating temperature. With defer_temp_wait the target was
+    // already raised before the tool change and the blocking wait belongs to the wipe tower
+    // generator, so there is nothing left to restore here.
+    if (m_ooze_prevention.enable && !defer_temp_wait)
         gcode += m_ooze_prevention.post_toolchange(*this);
 
     if (m_config.enable_pressure_advance.get_at(new_filament_id)) {

src/libslic3r/GCode.hpp

@@ -130,8 +130,11 @@ public:
 private:
     WipeTowerIntegration& operator=(const WipeTowerIntegration&);
     std::string append_tcr(GCode &gcodegen, const WipeTower::ToolChangeResult &tcr, int new_extruder_id, double z = -1.) const;
-    Polyline generate_path_to_wipe_tower(const Point &start_pos, const Point &end_pos, const BoundingBox &avoid_polygon, const BoundingBox &printer_bbx) const;
+    Polyline generate_path_to_wipe_tower(const Point &start_pos, const Point &end_pos, const BoundingBox &avoid_polygon, const Polygons &bed_polygons) const;
     std::string append_tcr2(GCode &gcodegen, const WipeTower::ToolChangeResult &tcr, int new_extruder_id, double z = -1.) const;
+    std::string travel_to_tower_gap(GCode &gcodegen, const Point &route_start, const Point &start_wipe_pos) const;
+    Vec2f transform_wt2_pt(const Vec2f &pt) const;
+    Polygons shared_printable_area(GCode &gcodegen) const;
 
     // Postprocesses gcode: rotates and moves G1 extrusions and returns result
     std::string post_process_wipe_tower_moves(const WipeTower::ToolChangeResult& tcr, const Vec2f& translation, float angle) const;
@@ -181,7 +184,7 @@ struct LayerResult {
     // It is used for the pressure equalizer because it needs to buffer one layer back.
     bool        nop_layer_result { false };
 
-    static LayerResult make_nop_layer_result() { return {"", std::numeric_limits<coord_t>::max(), false, false, true}; }
+    static LayerResult make_nop_layer_result() { return {"", std::numeric_limits<size_t>::max(), false, false, true}; }
 };
 
 class GCode {
@@ -259,7 +262,7 @@ public:
     std::string     retract(bool toolchange = false, bool is_last_retraction = false, LiftType lift_type = LiftType::NormalLift, bool apply_instantly = false, ExtrusionRole role = erNone);
     // extra_retract forwards a PETG pre-extrusion over-extrusion; default 0 -> identical to the plain deretract.
     std::string     unretract(float extra_retract = 0.f) { return m_writer.unlift() + m_writer.unretract(extra_retract); }
-    std::string     set_extruder(unsigned int extruder_id, double print_z, bool by_object=false, int toolchange_temp_override = -1);
+    std::string     set_extruder(unsigned int extruder_id, double print_z, bool by_object=false, int toolchange_temp_override = -1, bool defer_temp_wait = false);
     bool is_BBL_Printer();
     WipeTowerType wipe_tower_type();
 
@@ -539,6 +542,40 @@ private:
     // Cache for custom seam enforcers/blockers for each layer.
     SeamPlacer                          m_seam_placer;
 
+    // One stop of the island-level tour: consecutive islands of a single instance. An instance
+    // can have several visits per layer when its islands are toured non-consecutively.
+    struct InstanceVisit
+    {
+        // Index into the per-filament InstanceToPrint vector.
+        size_t              instance_idx;
+        // Islands to print, in order (indices into ObjectByExtruder::islands). Empty: print all
+        // islands, ordered at extrusion time.
+        std::vector<size_t> islands;
+        // First visit of this instance this layer; skirt, brim and support are emitted here.
+        bool                first_visit;
+    };
+
+    // One node of the island-level tour, also used as cache key: identity plus quantized position.
+    struct IslandOrderNode
+    {
+        ObjectID object_id;
+        size_t   instance_id;
+        // Index into ObjectByExtruder::islands, or size_t(-1) for an instance without chainable
+        // islands (e.g. support only), which is toured as a single stop.
+        size_t   island_idx;
+        // Island centroid in G-code coordinates, quantized to 1 mm for cache stability.
+        Point    pos;
+        bool operator==(const IslandOrderNode &rhs) const {
+            return object_id == rhs.object_id && instance_id == rhs.instance_id &&
+                   island_idx == rhs.island_idx && pos == rhs.pos;
+        }
+    };
+
+    // Cache the per-filament island tour to avoid recomputing while the layer's island layout is
+    // unchanged. Key: filament_id. Value: {nodes the tour was computed from, resulting visits}.
+    std::map<unsigned int, std::pair<std::vector<IslandOrderNode>, std::vector<InstanceVisit>>>
+                                        m_ordering_cache;
+
     ExtrusionQualityEstimator m_extrusion_quality_estimator;
 
 

src/libslic3r/GCode/CoolingBuffer.cpp

@@ -844,7 +844,10 @@ std::string CoolingBuffer::apply_layer_cooldown(
             ironing_fan_control = false; // ORCA: Add support for ironing fan speed control
             ironing_fan_speed = 0; // ORCA: Add support for ironing fan speed control
         }
-        if (fan_speed_new != m_fan_speed) {
+        // A tool change may keep the same configured base fan speed while the physical fan is
+        // still running at the previous filament's overhang speed. Restore the base speed before
+        // emitting G-code for the new tool in that case.
+        if (fan_speed_new != m_fan_speed || (immediately_apply && m_current_fan_speed != fan_speed_new)) {
             m_fan_speed = fan_speed_new;
             m_current_fan_speed = fan_speed_new;
             if (immediately_apply)
@@ -1040,8 +1043,10 @@ std::string CoolingBuffer::apply_layer_cooldown(
                 new_gcode += GCodeWriter::set_fan(m_config.gcode_flavor, m_current_fan_speed, part_cooling_fan_min_pwm);
                 fan_speed_change_requests[CoolingLine::TYPE_FORCE_RESUME_FAN] = false;
             }
-            else
+            else {
                 new_gcode += GCodeWriter::set_fan(m_config.gcode_flavor, m_fan_speed, part_cooling_fan_min_pwm);
+                m_current_fan_speed = m_fan_speed;
+            }
             need_set_fan = false;
         }
         pos = line_end;

src/libslic3r/GCode/GCodeProcessor.cpp

@@ -1450,8 +1450,8 @@ void GCodeProcessor::run_post_process()
     // flag) runs none of this. It is pure data construction — it only fills m_filament_blocks /
     // m_extruder_blocks / m_machine_*_gcode_*_line_id and never touches the exported g-code, so even
     // the enable_pre_heating fleet stays byte-identical (nothing reads the blocks until the injection
-    // pass). In practice it also stays empty/degenerate today because no template/code yet emits the
-    // MACHINE_*_GCODE_* / NOZZLE_CHANGE_* / CP_TOOLCHANGE_WIPE markers it keys off.
+    // pass). The wipe tower emits the NOZZLE_CHANGE_* (ramming) and CP_TOOLCHANGE_WIPE markers this
+    // builder keys off; the MACHINE_*_GCODE_* markers come from the machine g-code templates.
     m_filament_blocks.clear();
     m_extruder_blocks.clear();
     m_machine_start_gcode_end_line_id = (unsigned int) (-1);
@@ -5926,8 +5926,11 @@ void GCodeProcessor::process_G10(const GCodeReader::GCodeLine& line)
     GCodeReader::GCodeLine g10;
     g10.set(Axis::E, -this->m_parser.config().retraction_length.get_at(m_extruder_id));
     g10.set(Axis::F,  this->m_parser.config().retraction_speed.get_at(m_extruder_id) * 60);
+    //Orca: Firmware retract emulation must not change the modal G1 feedrate.
+    const float feedrate = m_feedrate;
     --m_g1_line_id;
     process_G1(g10);
+    m_feedrate = feedrate;
 }
 
 void GCodeProcessor::process_G11(const GCodeReader::GCodeLine& line)
@@ -5936,8 +5939,11 @@ void GCodeProcessor::process_G11(const GCodeReader::GCodeLine& line)
     GCodeReader::GCodeLine g11;
     g11.set(Axis::E, this->m_parser.config().retraction_length.get_at(m_extruder_id) + this->m_parser.config().retract_restart_extra.get_at(m_extruder_id));
     g11.set(Axis::F, this->m_parser.config().deretraction_speed.get_at(m_extruder_id) * 60);
+    // Orca: Firmware unretract emulation must not change the modal G1 feedrate.
+    const float feedrate = m_feedrate;
     --m_g1_line_id;
     process_G1(g11);
+    m_feedrate = feedrate;
 }
 
 void GCodeProcessor::process_G20(const GCodeReader::GCodeLine& line)

src/libslic3r/GCode/OrderingStrategies.cpp

@@ -0,0 +1,435 @@
+// Print-object ordering strategies: implementation.
+// Consolidates TSP post-processing, Snake, and Best-of-Strategies.
+
+#include "OrderingStrategies.hpp"
+#include "../Geometry.hpp"
+#include "../ShortestPath.hpp"
+
+#include <algorithm>
+#include <cmath>
+#include <limits>
+#include <numeric>
+#include <unordered_map>
+#include <utility>
+#include <vector>
+
+namespace Slic3r {
+
+/* ====================================================================
+ * TSP post-processing utilities
+ * ==================================================================== */
+
+bool tsp_2opt_improve(std::vector<size_t>& path, const Points& centers, int max_passes)
+{
+    size_t pn = path.size();
+    if (pn <= 2) return false;
+
+    // Pre-compute edge lengths once per pass to avoid redundant norm() calls.
+    auto recompute_edges = [&]() {
+        std::vector<double> el(pn);
+        for (size_t i = 0; i < pn; ++i) {
+            size_t ni = (i + 1) % pn;
+            el[i] = (centers[path[i]].cast<double>() - centers[path[ni]].cast<double>()).norm();
+        }
+        return el;
+    };
+    std::vector<double> el = recompute_edges();
+
+    // Pre-compute squared edge lengths for early rejection in the inner loop.
+    auto recompute_edges_sq = [&]() {
+        std::vector<double> elsq(pn);
+        for (size_t i = 0; i < pn; ++i) {
+            size_t ni = (i + 1) % pn;
+            elsq[i] = (centers[path[i]].cast<double>() - centers[path[ni]].cast<double>()).squaredNorm();
+        }
+        return elsq;
+    };
+    std::vector<double> elsq = recompute_edges_sq();
+
+    bool improved = false;
+    for (int pass = 0; max_passes <= 0 || pass < max_passes; ++pass) {
+        size_t best_i = pn, best_j = pn;
+        double best_gain = 0;
+
+        for (size_t i = 0; i < pn; ++i) {
+            const Vec2d& pi   = centers[path[i]].cast<double>();
+            const Vec2d& p_in = centers[path[(i + 1) % pn]].cast<double>();
+            double d_i = el[i];
+            double d_i_sq = elsq[i];
+
+            for (size_t j = i + 2; j < pn; ++j) {
+                size_t j_next = (j + 1) % pn;
+                // Skip the swap that would reverse the entire cycle (removes both
+                // edges (0,1) and (pn-1,0), equivalent to traversing the cycle backwards).
+                if (i == 0 && j_next == 0) continue;
+
+                const Vec2d& pj   = centers[path[j]].cast<double>();
+                const Vec2d& p_jn = centers[path[j_next]].cast<double>();
+                double d_j = el[j];
+
+                // Early rejection using squared distances (avoids 2 sqrt calls).
+                double new_a_sq = (pj - pi).squaredNorm();
+                double new_b_sq = (p_jn - p_in).squaredNorm();
+                if (new_a_sq >= d_i_sq && new_b_sq >= elsq[j]) continue;
+
+                double new_a = std::sqrt(new_a_sq);
+                double new_b = std::sqrt(new_b_sq);
+                double gain = d_i + d_j - new_a - new_b;
+
+                if (gain > best_gain) {
+                    best_gain = gain;
+                    best_i = i; best_j = j;
+                }
+            }
+        }
+
+        if (best_i == pn) break;
+        improved = true;
+        // Reverse the best swap segment
+        std::reverse(path.begin() + best_i + 1, path.begin() + best_j + 1);
+
+        // Recompute edge lengths after reversal
+        el = recompute_edges();
+        elsq = recompute_edges_sq();
+    }
+    return improved;
+}
+
+// Fast bounding-box overlap test (rejects most non-intersecting pairs).
+static inline bool bboxes_overlap(const Point& a, const Point& b, const Point& c, const Point& d)
+{
+    return !(std::max(a.x(), b.x()) < std::min(c.x(), d.x()) ||
+             std::max(c.x(), d.x()) < std::min(a.x(), b.x()) ||
+             std::max(a.y(), b.y()) < std::min(c.y(), d.y()) ||
+             std::max(c.y(), d.y()) < std::min(a.y(), b.y()));
+}
+
+bool tsp_remove_crossings(std::vector<size_t>& path, const Points& centers)
+{
+    size_t pn = path.size();
+    if (pn <= 3) return false;
+
+    // Treat path as a cycle: include the closing edge (pn-1 -> 0), consistent with the other
+    // TSP helpers (2-opt, closing-edge rotation) that operate on the full cycle.
+    size_t n_edges = pn;
+
+    // Scan for first crossing; returns {i, j} or {npos, npos} if none.
+    auto find_crossing = [&]() -> std::pair<size_t, size_t> {
+        for (size_t i = 0; i < n_edges; ++i) {
+            const Point& ai = centers[path[i]];
+            const Point& bi = centers[path[(i + 1) % pn]];
+
+            for (size_t j = i + 2; j < n_edges; ++j) {
+                // Skip the (0, pn-1) pair: edges (0,1) and (pn-1,0) share node 0.
+                if (i == 0 && j == pn - 1) continue;
+
+                const Point& aj = centers[path[j]];
+                const Point& bj = centers[path[(j + 1) % pn]];
+
+                if (!bboxes_overlap(ai, bi, aj, bj)) continue;
+                if (Geometry::segments_intersect(ai, bi, aj, bj))
+                    return {i, j};
+            }
+        }
+        return {std::numeric_limits<size_t>::max(), std::numeric_limits<size_t>::max()};
+    };
+
+    // Process crossings one at a time: find first, reverse it, restart scan.
+    // Cap iterations to prevent infinite loops on collinear/overlapping segments.
+    int max_iters = static_cast<int>(pn * pn);
+    bool improved = false;
+    while (max_iters-- > 0) {
+        auto [ci, cj] = find_crossing();
+        if (ci == std::numeric_limits<size_t>::max()) break;
+        improved = true;
+        std::reverse(path.begin() + ci + 1, path.begin() + cj + 1);
+    }
+    return improved;
+}
+
+void tsp_rotate_minimize_closing(std::vector<size_t>& path, const Points& centers)
+{
+    size_t pn = path.size();
+    size_t best_start = 0;
+    double best_closing2 = std::numeric_limits<double>::max();
+    for (size_t start = 0; start < pn; ++start) {
+        size_t last = (start + pn - 1) % pn;
+        double d2 = (centers[path[start]].cast<double>() - centers[path[last]].cast<double>()).squaredNorm();
+        if (d2 < best_closing2) { best_closing2 = d2; best_start = start; }
+    }
+    std::rotate(path.begin(), path.begin() + best_start, path.end());
+}
+
+/* ====================================================================
+ * Snake ordering
+ * ==================================================================== */
+
+struct SnakeRow { double avg_y; std::vector<size_t> indices; };
+
+// --- Row threshold computation ---
+// Extract unique Y values and use the median gap between them to determine
+// the row threshold.
+static double compute_row_threshold(const std::vector<double>& sorted_ys,
+                                    double y_min, double y_max,
+                                    size_t n,
+                                    double fraction_of_y_range,
+                                    double min_threshold_um)
+{
+    constexpr double MIN_GAP_FILTER = 1.0;  // ignore sub-micron gaps (coord_t = 1/100mm)
+
+    // Extract unique Y values
+    std::vector<double> unique_ys;
+    unique_ys.reserve(sorted_ys.size());
+    unique_ys.push_back(sorted_ys[0]);
+    for (size_t i = 1; i < sorted_ys.size(); ++i) {
+        if (sorted_ys[i] - sorted_ys[i - 1] > MIN_GAP_FILTER)
+            unique_ys.push_back(sorted_ys[i]);
+    }
+
+    double fallback_threshold = (y_max - y_min) * fraction_of_y_range;
+    if (unique_ys.size() <= 1) {
+        return std::max(fallback_threshold, min_threshold_um);
+    }
+
+    // Compute gaps between consecutive unique Y values
+    std::vector<double> gaps;
+    gaps.reserve(unique_ys.size() - 1);
+    for (size_t i = 1; i < unique_ys.size(); ++i)
+        gaps.push_back(unique_ys[i] - unique_ys[i - 1]);
+
+    if (gaps.empty()) {
+        return std::max(fallback_threshold, min_threshold_um);
+    }
+
+    // Sort gaps to find the median
+    std::sort(gaps.begin(), gaps.end());
+    double median_gap = gaps[gaps.size() / 2];
+    double min_gap = gaps.front();
+
+    // Threshold: half the gap between consecutive unique Y values.
+    double threshold = (median_gap < min_gap * 1.5) ? min_gap * 0.5 : median_gap * 0.5;
+
+    bool has_row_structure;
+    if (unique_ys.size() * 2 <= n) {
+        has_row_structure = true;
+    } else {
+        // Single-column or sparse: uniform gaps indicate a deliberate grid
+        double max_gap = *std::max_element(gaps.begin(), gaps.end());
+        has_row_structure = (max_gap < min_gap * 2.0);
+    }
+
+    if (has_row_structure) {
+        // For grid-like data, use the gap-based threshold directly.
+        return threshold;
+    }
+
+    return std::max(fallback_threshold, min_threshold_um);
+}
+
+// --- Row grouping ---
+// Bin points into rows by quantising Y / threshold
+static std::vector<SnakeRow> group_into_rows(const Points& centers, double row_threshold)
+{
+    size_t n = centers.size();
+    std::unordered_map<int64_t, std::vector<size_t>> row_map;
+    for (size_t i = 0; i < n; ++i) {
+        int64_t y_key = static_cast<int64_t>(std::floor(static_cast<double>(centers[i].y()) / row_threshold));
+        row_map[y_key].push_back(i);
+    }
+
+    std::vector<SnakeRow> rows;
+    rows.reserve(row_map.size());
+    for (auto& [key, indices] : row_map) {
+        double avg_y = std::accumulate(indices.begin(), indices.end(), 0.0,
+            [&](double acc, size_t idx) { return acc + static_cast<double>(centers[idx].y()); })
+            / indices.size();
+        rows.push_back({avg_y, std::move(indices)});
+    }
+
+    std::sort(rows.begin(), rows.end(),
+              [](const SnakeRow& a, const SnakeRow& b) { return a.avg_y < b.avg_y; });
+
+    return rows;
+}
+
+// Sort each row by X and greedily pick the direction (left->right or right->left)
+// that minimises the transition distance from the previous row's endpoint.
+static std::vector<size_t> build_serpentine_path(const Points& centers,
+                                                  std::vector<SnakeRow>& rows)
+{
+    std::vector<size_t> path;
+    path.reserve(centers.size());
+
+    for (size_t ri = 0; ri < rows.size(); ++ri) {
+        auto& row = rows[ri].indices;
+        std::sort(row.begin(), row.end(),
+                  [&](size_t a, size_t b) { return centers[a].x() < centers[b].x(); });
+
+        if (ri == 0) {
+            path.insert(path.end(), row.begin(), row.end());
+        } else {
+            const Point& prev_end = centers[path.back()];
+            double dist_to_left  = (prev_end.cast<double>() - centers[row.front()].cast<double>()).squaredNorm();
+            double dist_to_right = (prev_end.cast<double>() - centers[row.back()].cast<double>()).squaredNorm();
+
+            if (dist_to_left <= dist_to_right)
+                path.insert(path.end(), row.begin(), row.end());
+            else
+                path.insert(path.end(), row.rbegin(), row.rend());
+        }
+    }
+
+    return path;
+}
+
+// Row-based serpentine traversal: detect rows, bin points, snake through them.
+static std::vector<size_t> row_serpentine_path(const Points& centers,
+                                                double fraction_of_y_range = 0.02,
+                                                double min_threshold_um = 1e4)
+{
+    if (centers.empty()) return {};
+
+    size_t n = centers.size();
+
+    // Collect and sort Y coordinates.
+    std::vector<double> sorted_ys;
+    sorted_ys.reserve(n);
+    for (const auto& p : centers) sorted_ys.push_back(static_cast<double>(p.y()));
+    std::sort(sorted_ys.begin(), sorted_ys.end());
+
+    auto [ymin, ymax] = std::minmax_element(sorted_ys.begin(), sorted_ys.end());
+    double y_min = *ymin, y_max = *ymax;
+
+    double row_threshold = compute_row_threshold(sorted_ys, y_min, y_max, n,
+                                                  fraction_of_y_range, min_threshold_um);
+
+    auto rows = group_into_rows(centers, row_threshold);
+    return build_serpentine_path(centers, rows);
+}
+
+std::vector<size_t> snake_core(const Points& centers)
+{
+    if (centers.empty()) return {};
+
+    std::vector<size_t> path = row_serpentine_path(centers);
+
+    for (int iter = 0; iter < 3; ++iter) {
+        bool improved = tsp_2opt_improve(path, centers);
+        improved |= tsp_remove_crossings(path, centers);
+        if (!improved) break;
+    }
+
+    return path;
+}
+
+std::vector<const PrintInstance*> chain_print_object_instances_snake(const std::vector<const PrintObject*>& print_objects, const Point* start_near)
+{
+    return chain_instances_with_core(print_objects, start_near, snake_core);
+}
+
+std::vector<const PrintInstance*> chain_print_object_instances_snake(const Print& print)
+{
+    return chain_print_object_instances_snake(print.objects().vector(), nullptr);
+}
+
+/* ====================================================================
+ * Best-of-strategies meta-strategy
+ * ==================================================================== */
+
+std::vector<const PrintInstance*> chain_print_object_instances_best_of(const std::vector<const PrintObject*>& print_objects, const Point* start_near)
+{
+    if (print_objects.empty())
+        return {};
+
+    // Run all strategies.
+    std::vector<std::vector<const PrintInstance*>> candidates;
+    candidates.push_back(chain_print_object_instances(print_objects, start_near));
+    candidates.push_back(chain_print_object_instances_snake(print_objects, start_near));
+
+    // Compute metrics for each candidate.
+    struct Candidate { double total_len; double max_edge; };
+    std::vector<Candidate> metrics;
+    metrics.reserve(candidates.size());
+
+    for (size_t i = 0; i < candidates.size(); ++i) {
+        double total = 0.0;
+        double mx = 0.0;
+        for (size_t j = 0; j < candidates[i].size(); ++j) {
+            size_t k = (j + 1) % candidates[i].size();
+            double d = (candidates[i][j]->shift.cast<double>() - candidates[i][k]->shift.cast<double>()).norm();
+            total += d;
+            if (d > mx) mx = d;
+        }
+        metrics.push_back({total, mx});
+    }
+
+    // Pick shortest total path; tiebreak on smallest max edge.
+    auto best_it = std::min_element(metrics.begin(), metrics.end(),
+        [](const Candidate& a, const Candidate& b) {
+            return a.total_len < b.total_len ||
+                   (a.total_len == b.total_len && a.max_edge < b.max_edge);
+        });
+    size_t best = static_cast<size_t>(std::distance(metrics.begin(), best_it));
+
+    return candidates[best];
+}
+
+std::vector<const PrintInstance*> chain_print_object_instances_best_of(const Print& print)
+{
+    return chain_print_object_instances_best_of(print.objects().vector(), nullptr);
+}
+
+/* ====================================================================
+ * Island-level ordering entry point
+ * ==================================================================== */
+
+std::vector<size_t> order_points_with_strategy(const Points& points, PrintOrder print_order, const Point* start_near)
+{
+    if (points.empty())
+        return {};
+
+    if (print_order != PrintOrder::Snake && print_order != PrintOrder::BestOfStrategies)
+        // Nearest neighbor + post-processing; honours start_near natively.
+        return chain_points_with_postprocessing(points, start_near);
+
+    auto run_snake = [&points, start_near]() {
+        std::vector<size_t> path = snake_core(points);
+        if (start_near != nullptr && !path.empty()) {
+            // Start the cycle at the point closest to start_near.
+            size_t best_start = 0;
+            double best_d2 = std::numeric_limits<double>::max();
+            for (size_t k = 0; k < points.size(); ++k) {
+                double d2 = (points[k].cast<double>() - start_near->cast<double>()).squaredNorm();
+                if (d2 < best_d2) { best_d2 = d2; best_start = k; }
+            }
+            auto it = std::find(path.begin(), path.end(), best_start);
+            if (it != path.begin() && it != path.end())
+                std::rotate(path.begin(), it, path.end());
+        } else {
+            tsp_rotate_minimize_closing(path, points);
+        }
+        return path;
+    };
+
+    if (print_order == PrintOrder::Snake)
+        return run_snake();
+
+    // Best-of: pick the shortest total cycle; tiebreak on smallest max edge.
+    std::vector<std::vector<size_t>> candidates;
+    candidates.emplace_back(chain_points_with_postprocessing(points, start_near));
+    candidates.emplace_back(run_snake());
+
+    size_t best      = 0;
+    double best_len  = std::numeric_limits<double>::max();
+    double best_edge = std::numeric_limits<double>::max();
+    for (size_t i = 0; i < candidates.size(); ++i) {
+        double len  = tsp_cycle_path_length(candidates[i], points);
+        double edge = tsp_max_edge_length(candidates[i], points);
+        if (len < best_len || (len == best_len && edge < best_edge)) {
+            best_len = len; best_edge = edge; best = i;
+        }
+    }
+    return candidates[best];
+}
+
+} // namespace Slic3r

src/libslic3r/GCode/OrderingStrategies.hpp

@@ -0,0 +1,148 @@
+// Print-object ordering strategies and shared TSP post-processing utilities.
+
+#ifndef slic3r_OrderingStrategies_hpp_
+#define slic3r_OrderingStrategies_hpp_
+
+#include "../libslic3r.h"
+#include "../Point.hpp"
+
+#ifndef SLIC3R_TEST_HARNESS
+#include "../Print.hpp"
+#endif
+
+#include <algorithm>
+#include <limits>
+#include <utility>
+#include <vector>
+
+namespace Slic3r {
+
+// --- Path improvement (operate on index vectors into `centers`) ---
+
+// 2-opt improvement: reverses segments that reduce total cycle path length.
+// Returns true if any improvement was made.
+bool tsp_2opt_improve(std::vector<size_t>& path, const Points& centers, int max_passes = 10);
+
+// Crossing removal: reverse any segment pair whose edges geometrically cross.
+// Returns true if any crossing was removed.
+bool tsp_remove_crossings(std::vector<size_t>& path, const Points& centers);
+
+// Rotate the cycle so the closing edge (last -> first) is minimized.
+void tsp_rotate_minimize_closing(std::vector<size_t>& path, const Points& centers);
+
+// Total Euclidean path length of a cycle (including closing edge).
+inline double tsp_cycle_path_length(const std::vector<size_t>& path, const Points& centers)
+{
+    if (path.size() < 2) return 0.0;
+    double total = 0.0;
+    for (size_t i = 0; i < path.size(); ++i) {
+        size_t next = (i + 1) % path.size();
+        total += (centers[path[i]].cast<double>() - centers[path[next]].cast<double>()).norm();
+    }
+    return total;
+}
+
+// Maximum edge length of a cycle (including closing edge).
+inline double tsp_max_edge_length(const std::vector<size_t>& path, const Points& centers)
+{
+    if (path.size() < 2) return 0.0;
+    double mx = 0.0;
+    for (size_t i = 0; i < path.size(); ++i) {
+        size_t next = (i + 1) % path.size();
+        double d = (centers[path[i]].cast<double>() - centers[path[next]].cast<double>()).norm();
+        if (d > mx) mx = d;
+    }
+    return mx;
+}
+
+
+
+#ifndef SLIC3R_TEST_HARNESS
+
+// --- Wrapper boilerplate ---
+
+// Collect instance centers from PrintObjects, optionally pre-rotate to honour
+// start_near, call a core algorithm, and map the result back to PrintInstance*.
+template<typename CoreFn>
+std::vector<const PrintInstance*> chain_instances_with_core(
+    const std::vector<const PrintObject*>& print_objects,
+    const Point* start_near,
+    CoreFn&& core_fn)
+{
+    Points instance_centers;
+    std::vector<std::pair<size_t, size_t>> instances;
+    for (size_t i = 0; i < print_objects.size(); ++i) {
+        const PrintObject& object = *print_objects[i];
+        for (size_t j = 0; j < object.instances().size(); ++j) {
+            instance_centers.emplace_back(object.instances()[j].shift);
+            instances.emplace_back(i, j);
+        }
+    }
+
+    if (instance_centers.empty()) return {};
+
+    // If start_near is provided, pre-rotate so closest point is first.
+    if (start_near != nullptr) {
+        size_t best_start = 0;
+        double best_d2 = std::numeric_limits<double>::max();
+        for (size_t k = 0; k < instance_centers.size(); ++k) {
+            double d2 = (instance_centers[k].cast<double>() - start_near->cast<double>()).squaredNorm();
+            if (d2 < best_d2) { best_d2 = d2; best_start = k; }
+        }
+        std::rotate(instance_centers.begin(), instance_centers.begin() + best_start, instance_centers.end());
+        std::rotate(instances.begin(), instances.begin() + best_start, instances.end());
+    }
+
+    auto path = core_fn(instance_centers);
+
+    // Rotate the cycle so the first element is the best starting point.
+    // When start_near is provided, pick the point closest to it (preserving
+    // the pre-rotation). Otherwise minimise the closing edge.
+    if (start_near != nullptr && !path.empty()) {
+        // Pre-rotation already put the closest point at index 0.
+        // Find where index 0 appears in the path and rotate it to the front.
+        auto it = std::find(path.begin(), path.end(), size_t(0));
+        if (it != path.begin())
+            std::rotate(path.begin(), it, path.end());
+    } else {
+        tsp_rotate_minimize_closing(path, instance_centers);
+    }
+
+    std::vector<const PrintInstance*> out;
+    out.reserve(path.size());
+    for (size_t step : path) {
+        out.emplace_back(&print_objects[instances[step].first]->instances()[instances[step].second]);
+    }
+    return out;
+}
+
+#endif // SLIC3R_TEST_HARNESS
+
+// --- Core algorithms (operate on raw Points, return index permutations) ---
+
+// Snake ordering: row grouping + serpentine traversal + post-processing.
+std::vector<size_t> snake_core(const Points& centers);
+
+#ifndef SLIC3R_TEST_HARNESS
+
+// --- Production wrappers ---
+
+// Snake ordering.
+std::vector<const PrintInstance*> chain_print_object_instances_snake(const std::vector<const PrintObject*>& print_objects, const Point* start_near);
+std::vector<const PrintInstance*> chain_print_object_instances_snake(const Print& print);
+
+// Best-of-strategies: run all strategies and return the shortest result.
+// Primary: shortest total path; secondary tiebreaker: smallest max edge.
+std::vector<const PrintInstance*> chain_print_object_instances_best_of(const std::vector<const PrintObject*>& print_objects, const Point* start_near);
+std::vector<const PrintInstance*> chain_print_object_instances_best_of(const Print& print);
+
+// Order raw points with the selected strategy, returning an index permutation. Island-level
+// counterpart of the chain_print_object_instances_* helpers. The returned cycle starts at the
+// point closest to start_near; orders without a dedicated strategy use nearest-neighbor chaining.
+std::vector<size_t> order_points_with_strategy(const Points& points, PrintOrder print_order, const Point* start_near);
+
+#endif // SLIC3R_TEST_HARNESS
+
+} // namespace Slic3r
+
+#endif /* slic3r_OrderingStrategies_hpp_ */

src/libslic3r/GCode/PrintExtents.cpp

@@ -143,7 +143,8 @@ BoundingBoxf get_wipe_tower_extrusions_extents(const Print &print, const coordf_
     double wipe_tower_y = print.config().wipe_tower_y.get_at(plate_idx) + plate_origin(1);
     Transform2d trafo =
         Eigen::Translation2d(wipe_tower_x, wipe_tower_y) *
-        Eigen::Rotation2Dd(Geometry::deg2rad(print.config().wipe_tower_rotation_angle.value));
+        Eigen::Rotation2Dd(Geometry::deg2rad(print.config().wipe_tower_rotation_angle.value)) *
+        Eigen::Translation2d(print.wipe_tower_data().rib_offset.cast<double>()); // tower-local rib-wall shift, zero unless rib
 
     BoundingBoxf bbox;
     for (const std::vector<WipeTower::ToolChangeResult> &tool_changes : print.wipe_tower_data().tool_changes) {

src/libslic3r/GCode/WipeTower.hpp

@@ -12,7 +12,7 @@
 #include "libslic3r/Polyline.hpp"
 #include "libslic3r/TriangleMesh.hpp"
 #include <unordered_set>
-
+#include "libslic3r/MultiNozzleUtils.hpp"
 namespace Slic3r
 {
 
@@ -20,6 +20,17 @@ class WipeTowerWriter;
 class PrintConfig;
 enum GCodeFlavor : unsigned char;
 
+// Cuts the tower wall polygon open at each skip point (a toolchange's entry position)
+// so the entry travel can pass through instead of crossing the printed wall. Defined in
+// WipeTower.cpp, shared by WipeTower and WipeTower2.
+Polylines construct_gap_for_skip_points(
+    const Polygon& polygon, const std::vector<Vec2f>& skip_points, float wt_width, float gap_length, Polygon& insert_skip_polygon);
+
+// Klipper acts on commands the instant it parses them, and its G4 reads only P (milliseconds),
+// so the zero-second and seconds-valued dwells every other flavor uses neither synchronize nor
+// pause there. Both defined in WipeTower.cpp, shared by WipeTower and WipeTower2.
+const char* flush_planner_queue_command(GCodeFlavor flavor); // finish queued moves, e.g. around M104/M109
+std::string wait_command(GCodeFlavor flavor, float seconds);  // pause for `seconds`
 
 class WipeTower
 {
@@ -34,7 +45,11 @@ public:
     static TriangleMesh                 its_make_rib_tower(float width, float depth, float height, float rib_length, float rib_width, bool fillet_wall);
     static TriangleMesh                 its_make_rib_brim(const Polygon& brim, float layer_height);
     static Polygon                      rib_section(float width, float depth, float rib_length, float rib_width, bool fillet_wall);
-    static Vec2f                        move_box_inside_box(const BoundingBox &box1, const BoundingBox &box2, int offset = 0);
+    // Translation that brings a footprint inside the printable outline, padded by offset. The prime
+    // tower is validated against the real outline (see layered_print_cleareance_valid), so clamping
+    // against the bounding box alone would leave it off a delta or hexagonal bed. box and polygons
+    // must share one scaled coordinate frame; the translation comes back in millimeters.
+    static Vec2f                        move_box_inside_polygon(const BoundingBox &box, const Polygons &polygons, coord_t offset = 0);
     static Polygon                      rounding_polygon(Polygon &polygon, double rounding = 2., double angle_tol = 30. / 180. * PI);
     struct Extrusion
     {
@@ -84,7 +99,6 @@ public:
         bool                    priming;
 
 		bool                    is_tool_change{false};
-        bool                    is_contact{false};
 		Vec2f                   tool_change_start_pos;
 
         // Pass a polyline so that normal G-code generator can do a wipe for us.
@@ -108,6 +122,7 @@ public:
         // executing the gcode finish_layer_tcr.
         bool is_finish_first = false;
 
+        bool               is_contact = false;
         NozzleChangeResult nozzle_change_result;
 
 		// Sum the total length of the extrusion.
@@ -122,6 +137,8 @@ public:
 			}
 			return e_length;
 		}
+		// Orca: set by WipeTower2 (non-BBL tower) to force a travel to the tower even when the
+		// previous position is unknown; read by WipeTowerIntegration::append_tcr2 (GCode.cpp).
 		bool force_travel = false;
 	};
 
@@ -162,15 +179,12 @@ public:
                                    bool priming,
                                    size_t old_tool,
                                    bool is_finish,
-                                   bool is_tool_change,
-                                   float purge_volume,
-                                   bool is_contact = false) const;
+		                           bool is_tool_change, float purge_volume, bool is_contact) const;
 
     ToolChangeResult construct_block_tcr(WipeTowerWriter& writer,
                                    bool priming,
                                    size_t filament_id,
-                                   bool is_finish,
-                                   float purge_volume) const;
+                                   bool is_finish, float purge_volume) const;
 
 
 	// x			-- x coordinates of wipe tower in mm ( left bottom corner )
@@ -184,9 +198,14 @@ public:
 	// Set the extruder properties.
     void set_extruder(size_t idx, const PrintConfig& config);
 
+    void set_shared_print_bed(const Polygons &bed) { m_shared_print_bed = bed; }
+    // Orca: has_filament_switcher is not a static PrintConfig member here, so it is pushed in from
+    // Print via a setter rather than read in the ctor. Device-set only.
+    void set_has_filament_switcher(bool v) { m_has_filament_switcher = v; }
 	// Appends into internal structure m_plan containing info about the future wipe tower
 	// to be used before building begins. The entries must be added ordered in z.
-	void plan_toolchange(float z_par, float layer_height_par, unsigned int old_tool, unsigned int new_tool, float wipe_volume = 0.f, float prime_volume = 0.f);
+    void plan_toolchange(float z_par, float layer_height_par, unsigned int old_tool, unsigned int new_tool, float wipe_volume_ec = 0.f, float wipe_volume_nc = 0.f, float prime_volume = 0.f);
+
 
 	// Iterates through prepared m_plan, generates ToolChangeResults and appends them to "result"
 	void generate(std::vector<std::vector<ToolChangeResult>> &result);
@@ -219,9 +238,6 @@ public:
 		}
 	}
 
-	void set_wipe_volume(std::vector<std::vector<float>>& wiping_matrix) {
-		wipe_volumes = wiping_matrix;
-	}
 
 	// Switch to a next layer.
 	void set_layer(
@@ -250,7 +266,6 @@ public:
 
 		// Calculate extrusion flow from desired line width, nozzle diameter, filament diameter and layer_height:
 		m_extrusion_flow = extrusion_flow(layer_height);
-
         // Advance m_layer_info iterator, making sure we got it right
 		while (!m_plan.empty() && m_layer_info->z < print_z - WT_EPSILON && m_layer_info+1 != m_plan.end())
 			++m_layer_info;
@@ -309,20 +324,9 @@ public:
     std::vector<float> get_used_filament() const { return m_used_filament_length; }
     int get_number_of_toolchanges() const { return m_num_tool_changes; }
 
-	void set_filament_map(const std::vector<int> &filament_map) { m_filament_map = filament_map; }
-	// Vortek H2C: filament_id → physical nozzle_id for carousel rotation detection
-	void set_filament_nozzle_map(const std::vector<int> &nozzle_map) { m_filament_nozzle_map = nozzle_map; }
-
 	void set_has_tpu_filament(bool has_tpu) { m_has_tpu_filament = has_tpu; }
+
     bool has_tpu_filament() const { return m_has_tpu_filament; }
-
-    // Orca: has_filament_switcher is not a static PrintConfig member, so it is pushed in from Print
-    // via a setter rather than read in the ctor. Device-set only.
-    void set_has_filament_switcher(bool v) { m_has_filament_switcher = v; }
-    // The region every extruder can reach, used to clamp the PETG pre-extrusion offset to the
-    // printable bed.
-    void set_shared_print_bed(const Polygons &bed) { m_shared_print_bed = bed; }
-
     struct FilamentParameters {
         std::string 	    material = "PLA";
         int                 category;
@@ -331,15 +335,15 @@ public:
         bool                is_support = false;
         int  			    nozzle_temperature = 0;
         int  			    nozzle_temperature_initial_layer = 0;
-        int                 interface_print_temperature = 0;
-        float               loading_speed = 0.f;
-        float               loading_speed_start = 0.f;
-        float               unloading_speed = 0.f;
-        float               unloading_speed_start = 0.f;
-        float               delay = 0.f ;
-        int                 cooling_moves = 0;
-        float               cooling_initial_speed = 0.f;
-        float               cooling_final_speed = 0.f;
+        // BBS: remove useless config
+        //float               loading_speed = 0.f;
+        //float               loading_speed_start = 0.f;
+        //float               unloading_speed = 0.f;
+        //float               unloading_speed_start = 0.f;
+        //float               delay = 0.f ;
+        //int                 cooling_moves = 0;
+        //float               cooling_initial_speed = 0.f;
+        //float               cooling_final_speed = 0.f;
         float               ramming_line_width_multiplicator = 1.f;
         float               ramming_step_multiplicator = 1.f;
         float               max_e_speed = std::numeric_limits<float>::max();
@@ -349,41 +353,41 @@ public:
         float               retract_length;
         float               retract_speed;
         float               wipe_dist;
-        float               tower_interface_pre_extrusion_dist = 0.f;
-        float               tower_interface_pre_extrusion_length = 0.f;
-        // Outward shift of the wipe start for a PETG pre-extrusion on filament-switcher devices;
-        // set from filament_tower_interface_pre_extrusion_dist.
-        float               petg_pre_extrusion_offset_dist = 0.f;
-        float               tower_ironing_area = 4.f;
-        float               tower_interface_purge_length = 0.f;
-        // Distance (in mm of filament) that a hotend is allowed to pre-cool before the
-        // tower is reached; drives the prime-tower heating-during-wipe model (multi-nozzle only).
-        float               filament_cooling_before_tower = 0.f;
-        // .first = extruder change, .second = nozzle change (carousel)
-        std::pair<float,float>  max_e_ramming_speed{0.f, 0.f};
-        std::pair<float,float>  ramming_travel_time{0.f, 0.f};
-        std::pair<int,int>      precool_target_temp{0, 0};
-        std::pair<std::vector<float>,std::vector<float>> precool_t;
-        std::pair<std::vector<float>,std::vector<float>> precool_t_first_layer;
+        std::pair<float,float>  max_e_ramming_speed;//[0]extruder change [1]nozzle change
+        std::pair<float, float> ramming_travel_time; // Travel time after ramming
+        std::pair<std::vector<float>,std::vector<float>>  precool_t;//Pre-cooling time, set to 0 to ensure the ramming speed is controlled solely by ramming volumetric speed.
+        std::pair<std::vector<float>, std::vector<float>> precool_t_first_layer;
+        std::pair<int,int>    precool_target_temp;
+        float filament_cooling_before_tower = 0.f;
+        float flat_iron_area;
+        float filament_tower_interface_print_temp;
+        float filament_tower_interface_pre_extrusion_dist = 0;
+        float filament_tower_interface_pre_extrusion_length = 0;
+        float filament_petg_pre_extrusion_offset_dist = 0;
     };
 
 
-	void set_used_filament_ids(const std::vector<int> &used_filament_ids) { m_used_filament_ids = used_filament_ids; };
+    void set_used_filament_ids(const std::vector<int> &used_filament_ids) { m_used_filament_ids = used_filament_ids; };
     void set_filament_categories(const std::vector<int> & filament_categories) { m_filament_categories = filament_categories;};
-	std::vector<int> m_used_filament_ids;
+    void set_nozzle_group_result(const MultiNozzleUtils::LayeredNozzleGroupResult &multi_nozzle_group_result) { m_multi_nozzle_group_result = &multi_nozzle_group_result; };
+    std::vector<int> m_used_filament_ids;
     std::vector<int> m_filament_categories;
+    const MultiNozzleUtils::LayeredNozzleGroupResult *m_multi_nozzle_group_result{nullptr};
+
+    enum class WipeTowerLayerType : unsigned char { Normal, Contact, Solid, Contact_UP};// Contact layer should be solid and reduce feed
 
 	struct WipeTowerBlock
     {
         int              block_id{0};
         int              filament_adhesiveness_category{0};
         std::vector<float>      layer_depths;
-		std::vector<bool>       solid_infill;
+        //std::vector<bool>       solid_infill;
         std::vector<float>      finish_depth{0}; // the start pos of finish frame for every layer
+        std::vector<WipeTowerLayerType> layers_type;     // type of the layer, normal, Contact or Solid
         float            depth{0};
         float            start_depth{0};
         float            cur_depth{0};
-		int              last_filament_change_id{-1};
+        int              last_filament_change_id{-1};
         int              last_nozzle_change_id{-1};
 	};
 
@@ -403,25 +407,33 @@ public:
     WipeTowerBlock* get_block_by_category(int filament_adhesiveness_category, bool create);
     void add_depth_to_block(int filament_id, int filament_adhesiveness_category, float depth, bool is_nozzle_change = false);
 	int get_filament_category(int filament_id);
-	bool is_in_same_extruder(int filament_id_1, int filament_id_2);
-	// Vortek H2C: format BBS-compatible NOZZLE_CHANGE_START/END tag with OF/NF/ON/NN payload
-	std::string format_nozzle_change_tag(bool start, int old_filament_id, int new_filament_id) const;
 	void reset_block_status();
     int get_wall_filament_for_all_layer();
 	// for generate new wipe tower
     void generate_new(std::vector<std::vector<WipeTower::ToolChangeResult>> &result);
 
 	void plan_tower_new();
-	void generate_wipe_tower_blocks();
+	void generate_wipe_tower_blocks(bool add_solid_flag);
     void update_all_layer_depth(float wipe_tower_depth);
-
+    void set_nozzle_last_layer_id();
+    void set_first_layer_flow_ratio(const float flow_ratio);
+    // Orca: default/initial-layer/travel acceleration are object-scope options here (PrintConfig
+    // members in BBS), so Print pushes the resolved per-variant columns in via this setter.
+    void set_accelerations(const std::vector<double> &normal, const std::vector<double> &first_layer_normal,
+                           const std::vector<double> &travel, const std::vector<double> &first_layer_travel);
+    void calc_block_infill_gap();
     ToolChangeResult   tool_change_new(size_t new_tool, bool solid_change = false, bool solid_nozzlechange=false);
-    NozzleChangeResult nozzle_change_new(int old_filament_id, int new_filament_id, bool solid_change = false);
+    NozzleChangeResult ramming(int old_filament_id, int new_filament_id, bool solid_change = false, bool extruder_change = true); // extruder_chang means nozzle_change
     ToolChangeResult   finish_layer_new(bool extrude_perimeter = true, bool extrude_fill = true, bool extrude_fill_wall = true);
     ToolChangeResult   finish_block(const WipeTowerBlock &block, int filament_id, bool extrude_fill = true);
-    ToolChangeResult   finish_block_solid(const WipeTowerBlock &block, int filament_id, bool extrude_fill = true ,bool interface_solid =false);
+    ToolChangeResult   finish_block_solid(const WipeTowerBlock &block, int filament_id, bool extrude_fill = true, WipeTowerLayerType layer_type = WipeTowerLayerType::Normal);
     void toolchange_wipe_new(WipeTowerWriter &writer, const box_coordinates &cleaning_box, float wipe_length,bool solid_toolchange=false);
     Vec2f              get_rib_offset() const { return m_rib_offset; }
+    bool               is_need_ramming(int filament_id_1, int filament_id_2, int layer_id) const;
+    bool               is_same_extruder(int filament_id_1, int filament_id_2, int layer_id) const;
+    bool               is_same_nozzle(int filament_id_1, int filament_id_2, int layer_id) const;
+    int                get_nozzle_id(int filament_id, int layer_id) const;
+    int                get_extruder_id(int filament_id, int layer_id) const;
 
 private:
 	enum wipe_shape // A fill-in direction
@@ -441,7 +453,6 @@ private:
     bool   m_enable_wrapping_detection = false;
 	bool   m_enable_timelapse_print = false;
 	bool   m_semm               = true; // Are we using a single extruder multimaterial printer?
-	bool   m_purge_in_prime_tower = false; // Do we purge in the prime tower?
     Vec2f  m_wipe_tower_pos; 			// Left front corner of the wipe tower in mm.
 	float  m_wipe_tower_width; 			// Width of the wipe tower.
 	float  m_wipe_tower_depth 	= 0.f; 	// Depth of the wipe tower
@@ -459,12 +470,11 @@ private:
     float  m_travel_speed       = 0.f;
     float  m_first_layer_speed  = 0.f;
     size_t m_first_layer_idx    = size_t(-1);
-
-    std::vector<double> m_filaments_change_length;
+    Vec2f            m_origin;
+    std::vector<int>    m_last_layer_id;
+    std::pair<std::vector<double>,std::vector<double>> m_filaments_change_length;//[0]extruder change [1]nozzle change
     size_t       m_cur_layer_id;
     NozzleChangeResult m_nozzle_change_result;
-    std::vector<int>   m_filament_map;
-    std::vector<int>   m_filament_nozzle_map;  // Vortek H2C: filament_id → physical nozzle_id
     bool               m_has_tpu_filament{false};
     bool               m_is_multi_extruder{false};
     bool               m_use_gap_wall{false};
@@ -475,33 +485,32 @@ private:
     bool               m_used_fillet{false};
     Vec2f              m_rib_offset{Vec2f(0.f, 0.f)};
     bool               m_tower_framework{false};
-
+    bool               m_need_reverse_travel{false};
+    bool               m_enable_tower_interface_features{false};
 	// G-code generator parameters.
-    float           m_cooling_tube_retraction   = 0.f;
-    float           m_cooling_tube_length       = 0.f;
-    float           m_parking_pos_retraction    = 0.f;
-    float           m_extra_loading_move        = 0.f;
+    // BBS: remove useless config
+    //float           m_cooling_tube_retraction   = 0.f;
+    //float           m_cooling_tube_length       = 0.f;
+    //float           m_parking_pos_retraction    = 0.f;
+    //float           m_extra_loading_move        = 0.f;
     float           m_bridging                  = 0.f;
     bool            m_no_sparse_layers          = false;
-    bool            m_set_extruder_trimpot      = false;
+    // BBS: remove useless config
+    //bool            m_set_extruder_trimpot      = false;
     bool            m_adhesion                  = true;
     GCodeFlavor     m_gcode_flavor;
-
-    // Multi-nozzle prime-tower heating during wipe. m_is_multiple_nozzle gates the whole
-    // feature; it is false for every current (single-nozzle) printer (extruder_max_nozzle_count
-    // defaults to 1), so the pre-heat/pre-cool path is inert and wipe-tower g-code is unchanged.
-    bool                m_is_multiple_nozzle = false;
-    std::vector<double> m_hotend_heating_rate;     // config.hotend_heating_rate (deg/s per extruder)
-    std::vector<int>    m_physical_extruder_map;   // logical extruder -> physical tool number (M104 T param)
-
-    // Per-extruder printable-height clamp. m_printable_height = config.extruder_printable_height
-    // (per-extruder Z limit; empty for single-extruder printers, [320,325] for H2D). m_last_layer_id
-    // records, per extruder, the last wipe-tower layer that uses it. is_valid_last_layer() is gated on
-    // m_is_multi_extruder so single-extruder wipe-tower g-code is unchanged; the clamp only bites a
-    // multi-extruder wipe tower whose final per-extruder layer exceeds that extruder's printable
-    // height (near the Z limit).
-    std::vector<double> m_printable_height;
-    std::vector<int>    m_last_layer_id;
+    bool                      m_is_multiple_nozzle = false;
+    std::vector<unsigned int> m_normal_accels;
+    std::vector<unsigned int> m_first_layer_normal_accels;
+    std::vector<unsigned int> m_travel_accels;
+    std::vector<unsigned int> m_first_layer_travel_accels;
+    unsigned int              m_max_accels;
+    bool                      m_accel_to_decel_enable;
+    float                     m_accel_to_decel_factor;
+    bool                      m_enable_arc_fitting = true;
+    std::vector<double>       m_hotend_heating_rate;
+    std::vector<double>       m_hotend_cooling_rate;
+    Polygons                  m_shared_print_bed;
 
     // Bed properties
     enum {
@@ -512,10 +521,11 @@ private:
     float m_bed_width; // width of the bed bounding box
     Vec2f m_bed_bottom_left; // bottom-left corner coordinates (for rectangular beds)
 
+    float m_first_layer_flow_ratio;
 	float m_perimeter_width = 0.4f * Width_To_Nozzle_Ratio; // Width of an extrusion line, also a perimeter spacing for 100% infill.
     float m_nozzle_change_perimeter_width = 0.4f * Width_To_Nozzle_Ratio;
 	float m_extrusion_flow = 0.038f; //0.029f;// Extrusion flow is derived from m_perimeter_width, layer height and filament diameter.
-
+    std::unordered_map<int, std::pair<float,float>> m_block_infill_gap_width; // categories to infill_gap: toolchange gap, nozzlechange gap
 	// Extruder specific parameters.
     std::vector<FilamentParameters> m_filpar;
 
@@ -528,50 +538,52 @@ private:
 	// A fill-in direction (positive Y, negative Y) alternates with each layer.
 	wipe_shape   	m_current_shape = SHAPE_NORMAL;
     size_t 	m_current_tool  = 0;
-	// Orca: support mmu wipe tower
-    std::vector<std::vector<float>> wipe_volumes;
+	// BBS
+    //const std::vector<std::vector<float>> wipe_volumes;
 
 	float           m_depth_traversed = 0.f; // Current y position at the wipe tower.
     bool            m_current_layer_finished = false;
 	bool 			m_left_to_right   = true;
 	float			m_extra_spacing   = 1.f;
 	float           m_tpu_fixed_spacing = 2;
-    std::vector<Vec2f> m_wall_skip_points;
+    float           m_max_speed = 5400.f;  // the maximum printing speed on the prime tower.
+    std::vector<std::vector<Vec2f>> m_wall_skip_points;
     std::map<float,Polylines> m_outer_wall;
+    std::vector<double>        m_printable_height;
     bool is_first_layer() const { return size_t(m_layer_info - m_plan.begin()) == m_first_layer_idx; }
+    bool                       is_valid_last_layer(int tool, int layer_id, double layer_z) const;
     bool                       m_flat_ironing=false;
-    bool                       m_enable_tower_interface_features=false;
-    bool                       m_enable_tower_interface_cooldown_during_tower=false;
-    // Filament-switcher device flag + shared printable bed for the PETG pre-extrusion offset.
-    // m_has_filament_switcher is false for the whole shipping fleet (no profile sets the key), so
-    // the PETG branch in get_next_pos never runs -> no change fleet-wide.
-    bool                       m_has_filament_switcher=false;
-    Polygons                   m_shared_print_bed;
-    bool                       m_prev_layer_had_interface=false;
-    bool                       m_current_layer_has_interface=false;
+    bool                       m_contact_ironing = false;
+    bool                       m_has_filament_switcher = false;
+    float                      m_contact_speed   = 20 * 60.f;
+    std::vector<int>           m_physical_extruder_map;
 	// Calculates length of extrusion line to extrude given volume
 	float volume_to_length(float volume, float line_width, float layer_height) const {
 		return std::max(0.f, volume / (layer_height * (line_width - layer_height * (1.f - float(M_PI) / 4.f))));
 	}
-
+    // Calculates volume of extrusion line
+    float length_to_volume(float length,float line_width, float layer_height) const
+    {
+        return std::max(0.f, length * (layer_height * (line_width - layer_height * (1.f - float(M_PI) / 4.f))));
+    }
 	// Calculates depth for all layers and propagates them downwards
 	void plan_tower();
 
 	// Goes through m_plan and recalculates depths and width of the WT to make it exactly square - experimental
 	void make_wipe_tower_square();
 
-	Vec2f get_next_pos(const WipeTower::box_coordinates &cleaning_box, float wipe_length, bool interface_layer, size_t interface_tool);
+	Vec2f get_next_pos(const WipeTower::box_coordinates &cleaning_box, float wipe_length, bool solid_toolchange);
 
     // Goes through m_plan, calculates border and finish_layer extrusions and subtracts them from last wipe
     void save_on_last_wipe();
 
 	bool is_tpu_filament(int filament_id) const;
 	bool is_petg_filament(int filament_id) const;
-    bool is_need_reverse_travel(int filament_id, bool extruder_change) const;
-
+    bool is_need_reverse_travel(int filament, bool extruder_change) const;
 	// BBS
 	box_coordinates align_perimeter(const box_coordinates& perimeter_box);
 
+    void set_for_wipe_tower_writer(WipeTowerWriter &writer);
 
     // to store information about tool changes for a given layer
 	struct WipeTowerInfo{
@@ -584,6 +596,7 @@ private:
             float wipe_volume;
 			float wipe_length;
             float nozzle_change_depth{0};
+            float nozzle_change_length{0};
 			// BBS
 			float purge_volume;
             ToolChange(size_t old, size_t newtool, float depth=0.f, float ramming_depth=0.f, float fwl=0.f, float wv=0.f, float wl = 0, float pv = 0)
@@ -613,7 +626,7 @@ private:
     // ot -1 if there is no such toolchange.
     int first_toolchange_to_nonsoluble_nonsupport(
             const std::vector<WipeTowerInfo::ToolChange>& tool_changes) const;
-
+    WipeTowerInfo::ToolChange set_toolchange(int old_tool, int new_tool, float layer_height, float wipe_volume, float purge_volume,int layer_id);
 	void toolchange_Unload(
 		WipeTowerWriter &writer,
 		const box_coordinates  &cleaning_box,
@@ -633,13 +646,10 @@ private:
 		WipeTowerWriter &writer,
 		const box_coordinates  &cleaning_box,
 		float wipe_volume);
-    void get_wall_skip_points(const WipeTowerInfo &layer);
-
-    // Per-extruder printable-height clamp (see m_printable_height). is_valid_last_layer returns
-    // false only for a multi-extruder wipe tower's final per-extruder layer that exceeds that
-    // extruder's printable height; returns true (no clamp) in every other case.
-    bool is_valid_last_layer(int tool, int layer_id, double layer_z) const;
-    void set_nozzle_last_layer_id();
+    void get_wall_skip_points(const WipeTowerInfo &layer,int layer_id);
+    void get_all_wall_skip_points();
+    ToolChangeResult merge_tcr(ToolChangeResult &first, ToolChangeResult &second);
+    float            get_block_gap_width(int tool, bool is_nozzlechangle = false);
 };
 
 

src/libslic3r/GCode/WipeTower2.hpp

@@ -17,13 +17,20 @@ namespace Slic3r
 
 class WipeTowerWriter2;
 class PrintRegionConfig;
+class ConfigBase;
 
 class WipeTower2
 {
 public:
     static const std::string never_skip_tag() { return "_GCODE_WIPE_TOWER_NEVER_SKIP_TAG"; }
+    // Marks the wait-for-temp-on-wipe-tower M109 so the interface-temp deduplication pass
+    // in WipeTowerIntegration::append_tcr2 does not strip it.
+    static const std::string wait_for_temp_tag() { return ";_WAIT_FOR_TEMP_ON_WIPE_TOWER"; }
 	static std::pair<double, double> get_wipe_tower_cone_base(double width, double height, double depth, double angle_deg);
-	static std::vector<std::vector<float>> extract_wipe_volumes(const PrintConfig& config);
+	static std::vector<std::vector<float>> extract_wipe_volumes(const ConfigBase& config);
+	// Estimated total flush volume of a SEMM print with the given number of filaments,
+	// used to reserve wipe tower space before the tower is generated.
+	static float estimate_semm_flush_volume(const ConfigBase& config, size_t filaments_cnt);
 
     
     // Construct ToolChangeResult from current state of WipeTower2 and WipeTowerWriter2.
@@ -34,6 +41,15 @@ public:
 								   bool is_finish,
                                    bool is_contact = false) const;
 
+    // Whether this print cuts wall openings ("skip points") at the toolchange entries.
+    // Shared with the entry routing in GCode.cpp so the router and the tower agree.
+    static bool use_gap_wall(const PrintConfig& config);
+
+    // Whether the blocking toolchange temperature wait moves onto the wipe tower.
+    // Shared with the defer flag in GCode.cpp append_tcr2 so the deferral and the
+    // tower's tagged M109 can never disagree.
+    static bool wait_for_temp_enabled(const PrintConfig& config);
+
 	// x			-- x coordinates of wipe tower in mm ( left bottom corner )
 	// y			-- y coordinates of wipe tower in mm ( left bottom corner )
 	// width		-- width of wipe tower in mm ( default 60 mm - leave as it is )
@@ -69,9 +85,9 @@ public:
         const float brim = m_wipe_tower_brim_width_real;
         return BoundingBoxf(Vec2d(-brim, -brim), Vec2d(double(m_wipe_tower_width) + brim, double(m_wipe_tower_depth) + brim));
     }
-    // WT2 doesn't currently compute a rib-origin compensation like WipeTower (m_rib_offset),
-    // so expose a zero offset for consistency purposes (to maintain API parity).
-    Vec2f get_rib_offset() const { return Vec2f::Zero(); }
+    // Tower-local shift that puts the rib wall's first-layer min corner at the configured
+    // tower position, like WipeTower::get_rib_offset(). Zero unless the rib wall is used.
+    Vec2f get_rib_offset() const { return m_rib_offset; }
     float get_rib_width() const { return m_rib_width; }
     float get_rib_length() const { return m_rib_length; }
 
@@ -149,6 +165,7 @@ public:
     struct FilamentParameters {
         std::string 	    material = "PLA";
         bool                is_soluble = false;
+        bool                is_support = false;
         int  			    temperature = 0;
         int  			    first_layer_temperature = 0;
         int                 interface_print_temperature = 0;
@@ -220,9 +237,9 @@ private:
 	float  m_perimeter_speed    = 0.f;
     float  m_first_layer_speed  = 0.f;
     size_t m_first_layer_idx    = size_t(-1);
-    bool   m_flat_ironing       = false;
     bool   m_enable_tower_interface_features = false;
     bool   m_enable_tower_interface_cooldown_during_tower = false;
+    bool   m_wait_for_temp_on_wipe_tower = false;
     bool   m_prev_layer_had_interface = false;
     bool   m_current_layer_has_interface = false;
 
@@ -231,6 +248,12 @@ private:
     float  m_rib_width                    = 10;
     float  m_extra_rib_length             = 0;
     float  m_rib_length                   = 0;
+    Vec2f  m_rib_offset                   = Vec2f::Zero();
+    bool   m_use_gap_wall                 = false;
+    // Per plan layer, each toolchange's entry position (tower-local, un-shifted frame):
+    // where the wall is cut open so the entry travel does not cross the printed wall.
+    // Filled by compute_wall_skip_points() once the plan is final.
+    std::vector<std::vector<Vec2f>> m_wall_skip_points;
 
     bool   m_enable_arc_fitting           = false;
 
@@ -253,6 +276,7 @@ private:
     } m_bed_shape;
     float m_bed_width; // width of the bed bounding box
     Vec2f m_bed_bottom_left; // bottom-left corner coordinates (for rectangular beds)
+    Polygon m_bed_polygon; // printable_area contour (scaled)
 
 	float m_perimeter_width = 0.4f * Width_To_Nozzle_Ratio; // Width of an extrusion line, also a perimeter spacing for 100% infill.
 	float m_extrusion_flow = 0.038f; //0.029f;// Extrusion flow is derived from m_perimeter_width, layer height and filament diameter.
@@ -278,6 +302,37 @@ private:
 
     bool is_first_layer() const { return size_t(m_layer_info - m_plan.begin()) == m_first_layer_idx; }
 
+    // Purge row lattice of toolchange_Wipe(): row pitch and extrusion width.
+    float wipe_row_spacing(bool first_layer) const { return (first_layer ? m_extra_flow : m_extra_spacing_wipe) * m_perimeter_width; }
+    float wipe_line_width() const { return m_perimeter_width * m_extra_flow; }
+
+    // Whether toolchange_Unload() rams this (old) tool out.
+    bool tool_ramming_enabled(size_t tool) const { return (m_semm && m_enable_filament_ramming) || m_filpar[tool].multitool_ramming; }
+    // Whether the wipe restarts at the box boundary on a fresh row below the quantized
+    // ram band after ramming this (old) tool out (multi-tool gap wall; SEMM keeps the
+    // stock continue-from-ram-end behavior).
+    bool boundary_wipe_start_enabled(size_t tool) const { return tool_ramming_enabled(tool) && !m_semm && m_use_gap_wall; }
+
+    // With a boundary wipe start the wipe begins on a fresh row below the quantized ram
+    // band. Y offset from the box start to that first wipe row.
+    float wipe_start_offset_after_ram(float ramming_depth, bool first_layer) const
+    {
+        return ramming_depth + wipe_row_spacing(first_layer) - (m_perimeter_width + wipe_line_width()) / 2.f;
+    }
+
+    // Tower-local entry position of a toolchange whose box starts depth_traversed into
+    // the layer: the box corner, moved down to the first wipe row when the plan gives
+    // it a boundary wipe start (ramming_depth > 0 iff the unload rams). tool_change()
+    // enters here and compute_wall_skip_points() cuts the wall gap here, so the routed
+    // entry, the gap and the wipe scrub all share one opening.
+    Vec2f toolchange_entry_pos(float depth_traversed, float ramming_depth, bool first_layer) const
+    {
+        Vec2f pos(m_perimeter_width / 2.f, m_perimeter_width / 2.f + depth_traversed);
+        if (!m_semm && m_use_gap_wall && ramming_depth > 0.f)
+            pos.y() += wipe_start_offset_after_ram(ramming_depth, first_layer);
+        return pos;
+    }
+
 	// Calculates extrusion flow needed to produce required line width for given layer height
 	float extrusion_flow(float layer_height = -1.f) const	// negative layer_height - return current m_extrusion_flow
 	{
@@ -328,9 +383,10 @@ private:
     std::vector<float> m_used_filament_length;
 	std::vector<std::pair<float, std::vector<float>>> m_used_filament_length_until_layer;
 
-    // Return index of first toolchange that switches to non-soluble extruder
-    // ot -1 if there is no such toolchange.
-    int first_toolchange_to_nonsoluble(
+    // Return the index of the toolchange whose new filament should print the layer's
+    // finish extrusions (sparse infill + wall + brim), or -1 to print them with the
+    // layer's incoming filament before any toolchange happens.
+    int first_toolchange_to_nonsoluble_nonsupport(
             const std::vector<WipeTowerInfo::ToolChange>& tool_changes) const;
 
 	void toolchange_Unload(
@@ -343,7 +399,9 @@ private:
 	void toolchange_Change(
 		WipeTowerWriter2 &writer,
         const size_t		new_tool,
-		const std::string& 		new_material);
+		const std::string& 		new_material,
+		const int 				wait_for_temp,
+		const bool 				wait_beside_tower);
 	
 	void toolchange_Load(
 		WipeTowerWriter2 &writer,
@@ -353,7 +411,9 @@ private:
 		WipeTowerWriter2 &writer,
 		const WipeTower::box_coordinates  &cleaning_box,
 		float wipe_volume,
-        bool interface_layer);
+        bool interface_layer,
+        bool priming = false,
+        bool fill_box = false);
 
 
     Polygon generate_support_rib_wall(WipeTowerWriter2&                 writer,
@@ -361,8 +421,7 @@ private:
                                       double                 feedrate,
                                       bool                   first_layer,
                                       bool                   rib_wall,
-                                      bool                   extrude_perimeter,
-                                      bool                   skip_points);
+                                      bool                   extrude_perimeter);
 
     Polygon generate_support_cone_wall(
         WipeTowerWriter2& writer, 
@@ -372,6 +431,12 @@ private:
 		float spacing);
 
     Polygon generate_rib_polygon(const WipeTower::box_coordinates& wt_box);
+
+    void compute_wall_skip_points();
+
+    // Computes the depth reserved for a toolchange (shared by plan_toolchange() and the
+    // rib-wall square-tower replanning in generate()).
+    WipeTowerInfo::ToolChange set_toolchange(size_t old_tool, size_t new_tool, float layer_height, float wipe_volume, bool first_layer_plan);
 };
 
 

src/libslic3r/GCodeWriter.cpp

@@ -3,6 +3,7 @@
 #include "I18N.hpp"
 #include "PrintConfig.hpp"
 #include "ClipperUtils.hpp"
+#include "Geometry/ArcWelder.hpp"
 #include "Line.hpp"
 #include <algorithm>
 #include <iomanip>
@@ -1018,45 +1019,48 @@ std::string GCodeWriter::_spiral_travel_to_z(double z, const Vec2d &ij_offset, c
     }
 
     if (!this->config.enable_arc_fitting) { // Orca: if arc fitting is disabled, approximate the arc with small linear segments
-        std::ostringstream oss;
         const double z_start = m_pos(2); // starting Z height
 
-        // --------------------------------------------------------------------
-        // Determine number of segments based on Resolution
-        // --------------------------------------------------------------------
-        const double ref_resolution = 0.01; // reference resolution in mm
-        const double ref_segments  = 8.0;  // reference number of segments at reference resolution
-        
-        // number of linear segments to use for approximating the arc, clamp between 4 and 16
-        const int segments = std::clamp(int(std::round(ref_segments * (ref_resolution / m_resolution))), 4, 16);
-        // --------------------------------------------------------------------
-
         const double px = m_pos(0) - m_x_offset;        // take plate offset into consideration
         const double py = m_pos(1) - m_y_offset;        // take plate offset into consideration
         const double cx = px + ij_offset(0);            // center x
         const double cy = py + ij_offset(1);            // center y
         const double radius = ij_offset.norm();         // radius
+
+        // Number of linear segments approximating the circle, chosen so that a chord never deviates
+        // from the true arc by more than the slicing resolution. A resolution of 0 means "no
+        // simplification", which has no finite segment count, so it takes the upper bound.
+        constexpr size_t min_segments = 8;              // keep a small spiral visibly round
+        constexpr size_t max_segments = 128;            // bound the emitted G-code
+        const int segments = int(m_resolution > 0. ?
+            std::clamp(Geometry::ArcWelder::arc_discretization_steps(radius, 2. * M_PI, m_resolution), min_segments, max_segments) :
+            max_segments);
+
         const double a0 = std::atan2(py - cy, px - cx); // start angle
-        const double delta = 2.0 * M_PI;                // CCW full circle
 
-        if (full_gcode_comment)
-            oss << ";" << comment << "\n";
+        auto emit_point = [&output](const Vec3d &point) {
+            GCodeG1Formatter w;
+            w.emit_xyz(point);
+            output += w.string();
+        };
 
-        oss << "G1 F" << (speed * 60.0) << "\n";  // set feedrate
+        output.reserve(size_t(segments) * 40);          // ~40 characters per emitted G1 line
+
+        GCodeG1Formatter w;                             // set feedrate
+        w.emit_f(speed * 60.0);
+        w.emit_comment(GCodeWriter::full_gcode_comment, comment);
+        output += w.string();
 
         // approximate the arc with small linear segments (without the last point which is added later to ensure exactness)
         for (int i = 1; i < segments; ++i) {
-            double t = double(i) / segments;            // parametric position along arc
-            double a = a0 + delta * t;                  // CCW arc param
-            double x = cx + radius * std::cos(a);       // point on circle
-            double y = cy + radius * std::sin(a);       // point on circle
-            double zz = z_start + (z - z_start) * t;    // interpolated Z height
-
-            oss << "G1 X" << x << " Y" << y << " Z" << zz << "\n";
+            const double t = double(i) / segments;      // parametric position along arc
+            const double a = a0 + 2. * M_PI * t;        // CCW arc param, full circle
+            emit_point(Vec3d(cx + radius * std::cos(a), // point on circle
+                             cy + radius * std::sin(a),
+                             z_start + (z - z_start) * t)); // interpolated Z height
         }
 
-        oss << "G1 X" << px << " Y" << py << " Z" << z << "\n";  // final point to ensure exactness
-        output = oss.str();
+        emit_point(Vec3d(px, py, z));                   // final point to ensure exactness
     } else { // Orca: if arc fitting is enabled emit a G2/G3 command for the spiral lift
         output = std::string("G17") + (full_gcode_comment ? " ; XY plane for arc\n" : "\n");
 

src/libslic3r/Measure.hpp

@@ -94,7 +94,7 @@ public:
 
     void* volume{nullptr};
     std::vector<int>*    plane_indices{nullptr};
-    Transform3d                  world_tran;
+    Transform3d                  world_tran = Transform3d::Identity();
     std::shared_ptr<std::vector<SurfaceFeature>> world_plane_features{nullptr};
     std::shared_ptr<SurfaceFeature> origin_surface_feature{nullptr};
 

src/libslic3r/Orient.hpp

@@ -48,100 +48,50 @@ struct OrientMesh {
 
 };
 
-// params for minimizing support area
-struct OrientParamsArea {
-    float TAR_A = 0.015f;
-    float TAR_B = 0.177f;
-    float RELATIVE_F = 20;
-    float CONTOUR_F = 0.5f;
-    float BOTTOM_F = 2.5f;
-    float BOTTOM_HULL_F = 0.1f;
-    float TAR_C = 0.1f;
-    float TAR_D = 1;
-    float TAR_E = 0.0115f;
-    float FIRST_LAY_H = 0.2f;//0.0475;
-    float VECTOR_TOL = -0.00083f;
-    float NEGL_FACE_SIZE = 0.01f;
-    float ASCENT = -0.5f;
-    float PLAFOND_ADV = 0.0599f;
-    float CONTOUR_AMOUNT = 0.0182427f;
-    float OV_H = 2.574f;
-    float height_offset = 2.3728f;
-    float height_log = 0.041375f;
-    float height_log_k = 1.9325457f;
-    float LAF_MAX = 0.999f; // cos(1.4\degree) for low angle face 0.9997f
-    float LAF_MIN = 0.97f;  // cos(14\degree) 0.9703f
-    float TAR_LAF = 0.001f; //0.01f
-    float TAR_PROJ_AREA = 0.1f;
-    float BOTTOM_MIN = 0.1f;  // min bottom area. If lower than it the object may be unstable
-    float BOTTOM_MAX = 2000;  // max bottom area. If get to it the object is stable enough (further increase bottom area won't do more help)
-    float height_to_bottom_hull_ratio_MIN = 1;
-    float BOTTOM_HULL_MAX = 2000;// max bottom hull area
-    float APPERANCE_FACE_SUPP=3; // penalty of generating supports on appearance face
-
-    float overhang_angle = 60.f;
-    bool use_low_angle_face = true;
-    bool min_volume = false;
-    Eigen::Vector3f fun_dir;
-
-    /// Allow parallel execution.
-    bool parallel = true;
-
-    /// Progress indicator callback called when an object gets packed.
-    /// The unsigned argument is the number of items remaining to pack.
-    std::function<void(unsigned, std::string)> progressind = {};
-
-    /// A predicate returning true if abort is needed.
-    std::function<bool(void)>     stopcondition = {};
-
-    OrientParamsArea() = default;
-};
-
 struct OrientParams {
-    float TAR_A = 0.01f;//0.128f;
-    float TAR_B = 0.177f;
-    float RELATIVE_F= 6.610621027964314f;
-    float CONTOUR_F = 0.23228623269775997f;
-    float BOTTOM_F = 1.167152017941474f;
-    float BOTTOM_HULL_F = 0.1f;
-    float TAR_C = 0.24308070476924726f;
-    float TAR_D = 0.6284515508160871f;
-    float TAR_E = 0;//0.032157292647062234;
-    float FIRST_LAY_H = 0.2f;//0.029;
-    float VECTOR_TOL = -0.0011163303070972383f;
-    float NEGL_FACE_SIZE = 0.1f;
-    float ASCENT= -0.5f;
-    float PLAFOND_ADV = 0.04079208948120519f;
-    float CONTOUR_AMOUNT = 0.0101472219892684f;
-    float OV_H = 1.0370178217794535f;
-    float height_offset = 2.7417608343142073f;
-    float height_log = 0.06442030687034085f;
-    float height_log_k = 0.3933594673063997f;
-    float LAF_MAX = 0.999f; // cos(1.4\degree) for low angle face //0.9997f;
-    float LAF_MIN= 0.9703f;  // cos(14\degree) 0.9703f;
-    float TAR_LAF = 0.01f; //0.1f
-    float TAR_PROJ_AREA = 0.1f;
-    float BOTTOM_MIN = 0.1f;  // min bottom area. If lower than it the objects may be unstable
-    float BOTTOM_MAX = 2000; //400
-    float height_to_bottom_hull_ratio_MIN = 1;
-    float BOTTOM_HULL_MAX = 2000;// max bottom hull area to clip //600
-    float APPERANCE_FACE_SUPP=3; // penalty of generating supports on appearance face
-
-    float overhang_angle = 60.f;
-    bool use_low_angle_face = true;
-    bool min_volume = false;
-    Eigen::Vector3f fun_dir;
+    float TAR_A               { 0.01f };     // 0.128f;
+    float TAR_B               { 0.177f };
+    float RELATIVE_F          { 6.610621027964314f };
+    float CONTOUR_F           { 0.23228623269775997f };
+    float BOTTOM_F            { 1.167152017941474f };
+    float BOTTOM_HULL_F       { 0.1f };
+    float TAR_C               { 0.24308070476924726f };
+    float TAR_D               { 0.6284515508160871f };
+    float TAR_E               { 0};         // 0.032157292647062234;
+    float FIRST_LAY_H         { 0.2f};      // 0.029;
+    float VECTOR_TOL          { -0.0011163303070972383f };
+    float NEGL_FACE_SIZE      { 0.1f };
+    float ASCENT              { -0.5f };
+    float PLAFOND_ADV         { 0.04079208948120519f };
+    float CONTOUR_AMOUNT      { 0.0101472219892684f };
+    float OV_H                { 1.0370178217794535f };
+    float height_offset       { 2.7417608343142073f };
+    float height_log          { 0.06442030687034085f };
+    float height_log_k        { 0.3933594673063997f };
+    float LAF_MAX             { 0.999f };    // cos(1.4\degree) for low angle face //0.9997f;
+    float LAF_MIN             { 0.9703f };   // cos(14\degree) 0.9703f;
+    float TAR_LAF             { 0.01f };     // 0.1f
+    float TAR_PROJ_AREA       { 0.1f };
+    float BOTTOM_MIN          { 0.1f };      // min bottom area. If lower than it the objects may be unstable
+    float BOTTOM_MAX          { 2000 };      // 400
+    float height_to_bottom_hull_ratio_MIN { 1 };
+    float BOTTOM_HULL_MAX     { 2000 };      // max bottom hull area to clip //600
+    float APPERANCE_FACE_SUPP { 3 };         // penalty of generating supports on appearance face
 
+    float overhang_angle     { 60.f };
+    bool  use_low_angle_face { true };
+    bool  min_volume         { false };
+    Eigen::Vector3f fun_dir  {};
 
     /// Allow parallel execution.
-    bool parallel = false;
+    bool parallel { false };
 
     /// Progress indicator callback called when an object gets packed.
     /// The unsigned argument is the number of items remaining to pack.
-    std::function<void(unsigned, std::string)> progressind = {};
+    std::function<void(unsigned, std::string)> progressind {};
 
     /// A predicate returning true if abort is needed.
-    std::function<bool(void)>     stopcondition = {};
+    std::function<bool(void)> stopcondition {};
 
     OrientParams() = default;
 };

src/libslic3r/PerimeterGenerator.cpp

@@ -360,6 +360,14 @@ static ClipperLib_Z::Paths clip_extrusion(const ClipperLib_Z::Path& subject, con
     return clipped_paths;
 }
 
+static double clipper_z_path_length(const ClipperLib_Z::Path &path)
+{
+    double len = 0.;
+    for (size_t i = 1; i < path.size(); ++ i)
+        len += (Vec2d(double(path[i].x()), double(path[i].y())) - Vec2d(double(path[i - 1].x()), double(path[i - 1].y()))).norm();
+    return len;
+}
+
 struct PerimeterGeneratorArachneExtrusion
 {
     Arachne::ExtrusionLine* extrusion = nullptr;
@@ -571,17 +579,156 @@ static ExtrusionEntityCollection traverse_extrusions(const PerimeterGenerator& p
     return extrusion_coll;
 }
 
-// ORCA: only_one_wall_top detects the top as "slice − upper", so a feature rising from the middle of a
-// top surface becomes an enclosed hole that gets ringed with extra inner walls. Fill those holes back
-// into the top. Only holes that are both covered by the upper layer (excludes bridges) and backed by
-// solid material (excludes voids) are filled.
-static ExPolygons fill_enclosed_top_feature_holes(const ExPolygons &top, const Polygons &covered_by_upper, const ExPolygons &solid)
+// ORCA: only_one_wall_top acts on top surfaces, so without a top shell there is nothing for it to act on: zero top
+// shell layers retype the top surfaces as internal, see LayerRegion::prepare_fill_surfaces(). A 0% top surface
+// density does leave a top surface - just an unfilled one - so it does not disable the feature.
+// ConfigManipulation::toggle_print_fff_options() hides the option under the same condition, so a profile that left
+// it enabled does not act behind a hidden checkbox.
+static bool has_top_shell_layers(const PrintRegionConfig &config)
 {
-    ExPolygons filled = top;
-    for (ExPolygon &ex : filled)
-        ex.holes.clear();
-    const ExPolygons feature_holes = intersection_ex(intersection_ex(diff_ex(filled, top), covered_by_upper), solid);
-    return feature_holes.empty() ? top : union_ex(top, feature_holes);
+    return config.top_shell_layers.value > 0;
+}
+
+// ORCA: only_one_wall_first_layer thins the first layer to a single wall, the bottom counterpart of the above and
+// gated the same way: zero bottom shell layers retype the bottom surfaces as internal, so that wall would ring
+// sparse infill on the bed. The bottom surface density plays no part - an unfilled bottom surface is still a bottom
+// surface, exactly as for the top - and it cannot reach zero anyway, being capped at a 10% minimum.
+static bool has_bottom_shell_layers(const PrintRegionConfig &config)
+{
+    return config.bottom_shell_layers.value > 0;
+}
+
+// ORCA: the inner walls are only given up when a top fill takes their space, and it has to actually reach it -
+// a 0% top surface density leaves no fill at all, and without top_surface_expansion the fill never grows over
+// them. Either way the original generation is kept (re-onion the not-top region), which is what users of
+// only_one_wall_top alone have always got.
+static bool top_fill_replaces_inner_walls(const PrintRegionConfig &config)
+{
+    return has_top_shell_layers(config) && config.top_surface_density.value > 0 && config.top_surface_expansion.value > 0;
+}
+
+// ORCA: only_one_wall_top - cheap per-vertex classification of a wall against the top surface. Only Partial
+// needs the geometry clipped or measured; a segment crossing the top with no vertex inside is rare enough to ignore.
+enum class TopOverlap { None, Partial, Full };
+
+static bool point_over_top(const Point &p, const ExPolygons &top_region, const BoundingBox &top_region_bbox)
+{
+    if (! top_region_bbox.contains(p))
+        return false;
+    for (const ExPolygon &ex : top_region)
+        if (ex.contains(p, false))
+            return true;
+    return false;
+}
+
+static TopOverlap classify_over_top(const Points &pts, const ExPolygons &top_region, const BoundingBox &top_region_bbox)
+{
+    size_t inside = 0;
+    for (const Point &p : pts)
+        if (point_over_top(p, top_region, top_region_bbox))
+            ++ inside;
+    return inside == 0 ? TopOverlap::None : inside == pts.size() ? TopOverlap::Full : TopOverlap::Partial;
+}
+
+static TopOverlap classify_over_top(const Arachne::ExtrusionLine &el, const ExPolygons &top_region, const BoundingBox &top_region_bbox)
+{
+    size_t inside = 0;
+    for (const Arachne::ExtrusionJunction &j : el.junctions)
+        if (point_over_top(j.p, top_region, top_region_bbox))
+            ++ inside;
+    return inside == 0 ? TopOverlap::None : inside == el.junctions.size() ? TopOverlap::Full : TopOverlap::Partial;
+}
+
+// ORCA: only_one_wall_top for Arachne - cut out of the already generated inner walls the parts running over the top
+// surface, so geometry that continues upward keeps its walls. A wall too short over the top to be worth slitting open
+// is left whole, its footprint reported in kept_over_top for the caller to withhold from the top fill.
+static void clip_inner_walls_over_top(std::vector<Arachne::VariableWidthLines> &inner_perimeters, const ExPolygons &top_region, coord_t perimeter_width, Polygons &kept_over_top)
+{
+    const BoundingBox top_region_bbox = get_extents(top_region).inflated(SCALED_EPSILON);
+    auto covered_by = [](const Arachne::ExtrusionLine &el) {
+        Polyline centerline;
+        centerline.points.reserve(el.junctions.size());
+        coord_t width = 0;
+        for (const Arachne::ExtrusionJunction &j : el.junctions) {
+            centerline.points.emplace_back(j.p);
+            width = std::max(width, j.w);
+        }
+        return offset(centerline, float(width) / 2.f);
+    };
+    // Pull the cut back by half a wall width: the clip severs the centerline, but the bead's rounded end
+    // extends half a width past its endpoint and would otherwise overlap the top fill.
+    ClipperLib_Z::Paths top_paths_z;
+    for (const Polygon &poly : to_polygons(offset_ex(top_region, float(perimeter_width) / 2.f))) {
+        top_paths_z.emplace_back();
+        ClipperLib_Z::Path &out = top_paths_z.back();
+        out.reserve(poly.points.size());
+        for (const Point &pt : poly.points)
+            out.emplace_back(pt.x(), pt.y(), 0);
+    }
+    for (Arachne::VariableWidthLines &inner_perimeter : inner_perimeters) {
+        Arachne::VariableWidthLines kept;
+        kept.reserve(inner_perimeter.size());
+        for (Arachne::ExtrusionLine &el : inner_perimeter) {
+            if (el.empty())
+                continue;
+            const TopOverlap overlap = classify_over_top(el, top_region, top_region_bbox);
+            if (overlap == TopOverlap::None) {
+                kept.emplace_back(std::move(el));
+                continue;
+            }
+            if (overlap == TopOverlap::Full)
+                continue; // the clip below would return nothing anyway
+            ClipperLib_Z::Path subject;
+            subject.reserve(el.size());
+            for (const Arachne::ExtrusionJunction &j : el.junctions)
+                subject.emplace_back(j.p.x(), j.p.y(), j.w);
+            ClipperLib_Z::Paths pieces = clip_extrusion(subject, top_paths_z, ClipperLib_Z::ctDifference);
+
+            // Clipper treats the subject as an open polyline, so it also cuts a closed loop at its (arbitrary)
+            // start vertex and may reverse pieces. Stitch pieces sharing an endpoint back together.
+            auto same_pt = [](const ClipperLib_Z::IntPoint &p, const ClipperLib_Z::IntPoint &q) {
+                return std::abs(p.x() - q.x()) <= SCALED_EPSILON && std::abs(p.y() - q.y()) <= SCALED_EPSILON;
+            };
+            for (size_t i = 0; i < pieces.size(); ++ i) {
+                for (size_t j = i + 1; j < pieces.size();) {
+                    ClipperLib_Z::Path &a = pieces[i];
+                    ClipperLib_Z::Path &b = pieces[j];
+                    if (same_pt(a.front(), b.front()) || same_pt(a.front(), b.back()))
+                        std::reverse(a.begin(), a.end());
+                    if (same_pt(a.back(), b.back()))
+                        std::reverse(b.begin(), b.end());
+                    if (same_pt(a.back(), b.front())) {
+                        a.insert(a.end(), b.begin() + 1, b.end());
+                        pieces.erase(pieces.begin() + j);
+                        j = i + 1; // the merged path has new endpoints, restart the scan
+                    } else
+                        ++ j;
+                }
+            }
+
+            // If the clip removed next to nothing, keep the loop untouched instead of slitting it open. The
+            // half-width pull-back above already costs about one width per crossing, hence two widths.
+            double kept_length = 0.;
+            for (const ClipperLib_Z::Path &path : pieces)
+                kept_length += clipper_z_path_length(path);
+            if (clipper_z_path_length(subject) - kept_length < 2. * double(perimeter_width)) {
+                append(kept_over_top, covered_by(el));
+                kept.emplace_back(std::move(el));
+                continue;
+            }
+
+            for (const ClipperLib_Z::Path &path : pieces) {
+                Arachne::ExtrusionLine clipped(el.inset_idx, el.is_odd);
+                clipped.junctions.reserve(path.size());
+                for (const ClipperLib_Z::IntPoint &pt : path)
+                    clipped.junctions.emplace_back(Point(pt.x(), pt.y()), coord_t(pt.z()), el.inset_idx);
+                // Discard tiny leftovers that would print as zits.
+                if (clipped.size() >= 2 && clipped.getLength() >= perimeter_width)
+                    kept.emplace_back(std::move(clipped));
+            }
+        }
+        inner_perimeter = std::move(kept);
+    }
 }
 
 void PerimeterGenerator::split_top_surfaces(const ExPolygons &orig_polygons, ExPolygons &top_fills,
@@ -649,7 +796,6 @@ void PerimeterGenerator::split_top_surfaces(const ExPolygons &orig_polygons, ExP
     ExPolygons delete_bridge = diff_ex(orig_polygons, bridge_checker, ApplySafetyOffset::Yes);
 
     ExPolygons top_polygons = diff_ex(delete_bridge, upper_polygons_series_clipped, ApplySafetyOffset::Yes);
-    top_polygons = fill_enclosed_top_feature_holes(top_polygons, upper_polygons_series_clipped, orig_polygons);
 
     // get the not-top surface, from the "real top" but enlarged by external_infill_margin (and the
     // min_width_top_surface we removed a bit before)
@@ -1234,6 +1380,11 @@ void PerimeterGenerator::process_classic()
     for (const Surface &surface : all_surfaces)
         surface_exp.push_back(surface.expolygon);
     std::vector<size_t> surface_order = chain_expolygons(surface_exp);
+    // ORCA: neither one-wall option has a surface to act on without the shell behind it, see
+    // has_top_shell_layers() / has_bottom_shell_layers(). Gated here so every use below - including the
+    // topmost and first layers - sees the same answer.
+    const bool only_one_wall_top         = this->config->only_one_wall_top && has_top_shell_layers(*this->config);
+    const bool only_one_wall_first_layer = this->config->only_one_wall_first_layer && has_bottom_shell_layers(*this->config);
     for (size_t order_idx = 0; order_idx < surface_order.size(); order_idx++) {
         const Surface &surface = all_surfaces[surface_order[order_idx]];
         // detect how many perimeters must be generated for this island
@@ -1241,16 +1392,23 @@ void PerimeterGenerator::process_classic()
         int sparse_infill_density = this->config->sparse_infill_density.value;
         if (this->config->alternate_extra_wall && this->layer_id % 2 == 1 && !m_spiral_vase && sparse_infill_density > 0) // add alternating extra wall
             loop_number++;
-        if (this->layer_id == object_config->raft_layers && this->config->only_one_wall_first_layer)
+        if (this->layer_id == object_config->raft_layers && only_one_wall_first_layer)
             loop_number = 0;
         // Set the topmost layer to be one wall
-        if (loop_number > 0 && config->only_one_wall_top && this->upper_slices == nullptr)
+        if (loop_number > 0 && only_one_wall_top && this->upper_slices == nullptr)
             loop_number = 0;
 
         ExPolygons last        = union_ex(surface.expolygon.simplify_p(surface_simplify_resolution));
         ExPolygons gaps;
         ExPolygons top_fills;
         ExPolygons fill_clip;
+        // ORCA: only_one_wall_top, all empty unless this island has a top surface on this layer. See the
+        // post-onion reduction below: the region to keep clear of inner walls, the space freed by the dropped
+        // walls (goes to infill, not left as a void) and the space held by the kept ones (withheld from the fill).
+        ExPolygons one_wall_top_region;
+        ExPolygons one_wall_top_reclaimed;
+        Polygons   one_wall_top_kept_bands;
+        bool       apply_one_wall_top = false;
         if (loop_number >= 0) {
             // In case no perimeters are to be generated, loop_number will equal to -1.
             std::vector<PerimeterGeneratorLoops> contours(loop_number+1);    // depth => loops
@@ -1389,8 +1547,19 @@ void PerimeterGenerator::process_classic()
 
                 //BBS: refer to superslicer
                 //store surface for top infill if only_one_wall_top
-                if (i == 0 && i!=loop_number && config->only_one_wall_top && !surface.is_bridge() && this->upper_slices != NULL) {
-                    this->split_top_surfaces(last, top_fills, last, fill_clip);
+                if (i == 0 && i!=loop_number && only_one_wall_top && !surface.is_bridge() && this->upper_slices != NULL) {
+                    if (top_fill_replaces_inner_walls(*this->config)) {
+                        // ORCA: take the top fill and the keep-out region but leave `last` as the real geometry,
+                        // so the onion follows it and the walls over the top are reduced in one step below.
+                        ExPolygons non_top_polygons;
+                        this->split_top_surfaces(last, top_fills, non_top_polygons, fill_clip);
+                        apply_one_wall_top = !top_fills.empty();
+                        if (apply_one_wall_top)
+                            one_wall_top_region = diff_ex(last, non_top_polygons);
+                    } else {
+                        // Onion the not-top region only, so the remaining walls stop at the top boundary.
+                        this->split_top_surfaces(last, top_fills, last, fill_clip);
+                    }
                 }
 
                 if (i == loop_number && (! has_gap_fill || this->config->sparse_infill_density.value == 0)) {
@@ -1400,6 +1569,46 @@ void PerimeterGenerator::process_classic()
                 }
             }
 
+            // ORCA: only_one_wall_top reduction - drop the inner walls (depth > 0) running over the top surface and
+            // take that space back from the gaps, leaving the top with the outer wall and the top infill. Classic
+            // perimeters are closed loops, so a wall can only be kept or dropped whole; one that merely grazes the
+            // top (same tolerance as the Arachne clip) is kept and withheld from the top fill instead.
+            if (apply_one_wall_top) {
+                const BoundingBox top_region_bbox   = get_extents(one_wall_top_region).inflated(SCALED_EPSILON);
+                const double      grazing_tolerance = 2. * double(perimeter_width);
+                // The band a wall covers, taken around its centerline so the orientation of holes does not matter.
+                auto wall_band = [perimeter_spacing](const Polygon &poly) {
+                    Polygon centerline = poly;
+                    centerline.make_counter_clockwise();
+                    return diff(offset(centerline, float(perimeter_spacing) / 2.f),
+                                offset(centerline, -float(perimeter_spacing) / 2.f));
+                };
+                Polygons dropped_wall_bands;
+                auto reduce_over_top = [&](PerimeterGeneratorLoops &loops) {
+                    loops.erase(std::remove_if(loops.begin(), loops.end(), [&](const PerimeterGeneratorLoop &loop) {
+                        const TopOverlap overlap = classify_over_top(loop.polygon.points, one_wall_top_region, top_region_bbox);
+                        if (overlap == TopOverlap::None)
+                            return false;
+                        // Only a wall straddling the boundary is worth measuring; a wall wholly over the top goes.
+                        if (overlap == TopOverlap::Partial &&
+                            total_length(intersection_pl(Polylines{ loop.polygon.split_at_first_point() }, one_wall_top_region)) < grazing_tolerance) {
+                            append(one_wall_top_kept_bands, wall_band(loop.polygon));
+                            return false;
+                        }
+                        append(dropped_wall_bands, wall_band(loop.polygon));
+                        return true;
+                    }), loops.end());
+                };
+                for (int d = 1; d <= loop_number; ++ d) {
+                    reduce_over_top(contours[d]);
+                    reduce_over_top(holes[d]);
+                }
+                if (! gaps.empty())
+                    gaps = diff_ex(gaps, one_wall_top_region);
+                if (! dropped_wall_bands.empty())
+                    one_wall_top_reclaimed = diff_ex(dropped_wall_bands, one_wall_top_region);
+            }
+
             // nest loops: holes first
             for (int d = 0; d <= loop_number; ++ d) {
                 PerimeterGeneratorLoops &holes_d = holes[d];
@@ -1634,7 +1843,10 @@ void PerimeterGenerator::process_classic()
                     and use zigzag).  */
                 //FIXME Vojtech: This grows by a rounded extrusion width, not by line spacing,
                 // therefore it may cover the area, but no the volume.
-                last = diff_ex(last, gap_fill.polygons_covered_by_width(10.f));
+                Polygons gap_fill_covered = gap_fill.polygons_covered_by_width(10.f);
+                last = diff_ex(last, gap_fill_covered);
+                if (! one_wall_top_reclaimed.empty())
+                    one_wall_top_reclaimed = diff_ex(one_wall_top_reclaimed, gap_fill_covered);
                 this->gap_fill->append(std::move(gap_fill.entities));
 
 			}
@@ -1679,9 +1891,15 @@ void PerimeterGenerator::process_classic()
         // append infill areas to fill_surfaces
         //if any top_fills, grow them by ext_perimeter_spacing/2 to have the real un-anchored fill
         ExPolygons top_infill_exp = intersection_ex(fill_clip, offset_ex(top_fills, double(ext_perimeter_spacing / 2)));
+        // ORCA: only_one_wall_top - route the top fill around the walls kept despite grazing the top.
+        if (!one_wall_top_kept_bands.empty())
+            top_infill_exp = diff_ex(top_infill_exp, one_wall_top_kept_bands);
         if (!top_fills.empty()) {
             infill_exp = union_ex(infill_exp, offset_ex(top_infill_exp, double(top_infill_peri_overlap)));
         }
+        // ORCA: only_one_wall_top - what the top fill does not cover of the dropped walls goes to infill.
+        if (!one_wall_top_reclaimed.empty())
+            infill_exp = union_ex(infill_exp, one_wall_top_reclaimed);
         this->fill_surfaces->append(infill_exp, stInternal);
 
         apply_extra_perimeters(infill_exp);
@@ -1700,6 +1918,8 @@ void PerimeterGenerator::process_classic()
                     double(-inset - infill_peri_overlap));
             if (!top_fills.empty())
                 polyWithoutOverlap = union_ex(polyWithoutOverlap, top_infill_exp);
+            if (!one_wall_top_reclaimed.empty())
+                polyWithoutOverlap = union_ex(polyWithoutOverlap, one_wall_top_reclaimed);
             this->fill_no_overlap->insert(this->fill_no_overlap->end(), polyWithoutOverlap.begin(), polyWithoutOverlap.end());
         }
 
@@ -1757,7 +1977,7 @@ void PerimeterGenerator::process_no_bridge(Surfaces& all_surfaces, coord_t perim
             ExPolygons unsupported = diff_ex(last, *this->lower_slices, ApplySafetyOffset::Yes);
             if (!unsupported.empty()) {
                 //remove small overhangs
-                ExPolygons unsupported_filtered = offset2_ex(unsupported, double(-perimeter_spacing), double(perimeter_spacing));
+                ExPolygons unsupported_filtered = opening_ex(unsupported, perimeter_spacing);
 
                 if (!unsupported_filtered.empty()) {
                     //to_draw.insert(to_draw.end(), last.begin(), last.end());
@@ -1870,35 +2090,40 @@ void PerimeterGenerator::process_no_bridge(Surfaces& all_surfaces, coord_t perim
                                 //TODO: add other polys as holes inside this one (-margin)
                             } else { // if(this->config->counterbore_hole_bridging.value == chbBridges)
                                 // Orca: Partial counterbore bridging is mask-based. Preserve the supported
-                                // remainder (`last`) and use simplified BridgeDetector coverage to derive the
+                                // remainder and use simplified BridgeDetector coverage to derive the
                                 // bridgeable counterbore span. The span is grown from supported material,
-                                // shrunk back, stripped from `last`, and expanded back. It is then prevented
-                                // from intruding deeper into `last` than the explicit anchor overlap.
-                                // Finally, add the allowed anchor band from `last` then remove the
+                                // shrunk back, stripped from the remaining normal surface, and expanded back.
+                                // It is then prevented from intruding deeper into it than the explicit anchor overlap.
+                                // Finally, add the allowed anchor band from it then remove the
                                 // narrow hole-side wall contact, which must remain unbridgeable.
 
-                                last = diff_ex(last, unsupported_filtered, ApplySafetyOffset::Yes);
+                                const ExPolygons remaining = diff_ex(last, unsupported_filtered, ApplySafetyOffset::Yes);
 
                                 ExPolygons bridgeable_filtered;
+
                                 for (ExPolygon& poly : bridgeable) {
                                     poly.simplify(perimeter_spacing, &bridgeable_filtered);
                                 }
                                 bridgeable_filtered = opening_ex(bridgeable_filtered, ext_perimeter_width);
 
                                 // Get rid of coarseness of the resulted bridgeable area by using the original supported area as reference.
-                                // This is to avoid keeping tiny bridgeable areas that are far from the supported area, or protrude into it. 
-                                bridgeable_filtered = union_ex(offset_ex(last, perimeter_spacing), bridgeable_filtered);
+                                // This is to avoid keeping tiny bridgeable areas that are far from the supported area, or protrude into it.
+                                bridgeable_filtered = union_ex(offset_ex(remaining, perimeter_spacing), bridgeable_filtered);
                                 bridgeable_filtered = offset_ex(bridgeable_filtered, -perimeter_spacing);
-                                bridgeable_filtered = diff_ex(bridgeable_filtered, last, ApplySafetyOffset::Yes);
+                                bridgeable_filtered = diff_ex(bridgeable_filtered, remaining, ApplySafetyOffset::Yes);
                                 bridgeable_filtered = opening_ex(bridgeable_filtered, perimeter_spacing); // filter noise from the diff_ex
                                 bridgeable_filtered = offset_ex(bridgeable_filtered, perimeter_spacing);  // restore the size to the original bridgeable area
                                 // Safety measure: Keep the bridge mask from intruding deeper into the
-                                // supported anchor region (`last`) than the explicit anchor overlap.
-                                bridgeable_filtered = diff_ex(bridgeable_filtered, offset_ex(last, -bridge_anchor_offset));
+                                // supported anchor region than the explicit anchor overlap.
+                                bridgeable_filtered = diff_ex(bridgeable_filtered, offset_ex(remaining, -bridge_anchor_offset));
 
-                                ExPolygons bridge_anchor_areas = intersection_ex(last, offset_ex(unsupported_filtered, bridge_anchor_offset));
+                                ExPolygons bridge_anchor_areas = intersection_ex(remaining, offset_ex(unsupported_filtered, bridge_anchor_offset));
                                 unsupported_filtered = union_ex(bridgeable_filtered, bridge_anchor_areas); // add bridge anchor
                                 unsupported_filtered = opening_ex(unsupported_filtered, bridge_anchor_offset); // remove anchor area from hole-side walls, it must remain unbridgeable
+
+                                // update 'last' only if we have a valid bridgeable area, otherwise we will lose the original unsupported area
+                                if (!unsupported_filtered.empty())
+                                    last = remaining;
                                 // TODO: Fix the case with thin outer walls around the bridge (1~2 walls) where classic wall
                                 // might generate two walls in a tiny space or non at all if "Detect thin walls" is not activated
                             }
@@ -2138,6 +2363,11 @@ void PerimeterGenerator::process_arachne()
     process_no_bridge(all_surfaces, perimeter_spacing, ext_perimeter_width);
     // BBS: don't simplify too much which influence arc fitting when export gcode if arc_fitting is enabled
     double surface_simplify_resolution = (print_config->enable_arc_fitting && !this->has_fuzzy_skin) ? 0.2 * m_scaled_resolution : m_scaled_resolution;
+    // ORCA: neither one-wall option has a surface to act on without the shell behind it, see
+    // has_top_shell_layers() / has_bottom_shell_layers(). Gated here so every use below - including the
+    // topmost and first layers - sees the same answer.
+    const bool only_one_wall_top         = this->config->only_one_wall_top && has_top_shell_layers(*this->config);
+    const bool only_one_wall_first_layer = this->config->only_one_wall_first_layer && has_bottom_shell_layers(*this->config);
     // we need to process each island separately because we might have different
     // extra perimeters for each one
     for (const Surface& surface : all_surfaces) {
@@ -2150,12 +2380,12 @@ void PerimeterGenerator::process_arachne()
 
         // Set the bottommost layer to be one wall
         const bool is_bottom_layer = (this->layer_id == object_config->raft_layers) ? true : false;
-        if (is_bottom_layer && this->config->only_one_wall_first_layer)
+        if (is_bottom_layer && only_one_wall_first_layer)
             loop_number = 0;
 
         // Orca: set the topmost layer to be one wall according to the config
         const bool is_topmost_layer = (this->upper_slices == nullptr) ? true : false;
-        if (is_topmost_layer && loop_number > 0 && config->only_one_wall_top)
+        if (is_topmost_layer && loop_number > 0 && only_one_wall_top)
             loop_number = 0;
         
         auto apply_precise_outer_wall = config->precise_outer_wall && config->wall_sequence == WallSequence::InnerOuter;
@@ -2175,10 +2405,10 @@ void PerimeterGenerator::process_arachne()
         //PS: One wall top surface for Arachne
         ExPolygons top_expolygons;
         // Calculate how many inner loops remain when TopSurfaces is selected.
-        const int inner_loop_number = (config->only_one_wall_top && upper_slices != nullptr) ? loop_number - 1 : -1;
+        const int inner_loop_number = (only_one_wall_top && upper_slices != nullptr) ? loop_number - 1 : -1;
 
         // Set one perimeter when TopSurfaces is selected.
-        if (config->only_one_wall_top && loop_number > 0)
+        if (only_one_wall_top && loop_number > 0)
             loop_number = 0;
 
         Arachne::WallToolPathsParams input_params_tmp = input_params;
@@ -2209,7 +2439,6 @@ void PerimeterGenerator::process_arachne()
                 upper_slices_clipped = ClipperUtils::clip_clipper_polygons_with_subject_bbox(*upper_slices, infill_contour_bbox);
 
             top_expolygons = diff_ex(infill_contour, upper_slices_clipped);
-            top_expolygons = fill_enclosed_top_feature_holes(top_expolygons, upper_slices_clipped, infill_contour);
 
             if (!top_expolygons.empty()) {
                 if (lower_slices != nullptr) {
@@ -2230,25 +2459,33 @@ void PerimeterGenerator::process_arachne()
                 // due to thin lines being generated
                 top_expolygons = offset2_ex(top_expolygons, -top_surface_min_width, top_surface_min_width + float(perimeter_width * 0.85));
 
-                // Get the not-top ExPolygons (including bridges) from current slices and expanded real top ExPolygons (without bridges).
-                const ExPolygons not_top_expolygons = diff_ex(infill_contour, top_expolygons);
-
-                // Get final top ExPolygons.
+                // Get final top ExPolygons (bridges were excluded above, so they stay walled).
                 top_expolygons = intersection_ex(top_expolygons, infill_contour);
 
-                const Polygons not_top_polygons = to_polygons(offset_ex(not_top_expolygons,wall_0_inset));
-                Arachne::WallToolPaths inner_wall_tool_paths(not_top_polygons, perimeter_spacing, perimeter_spacing, coord_t(inner_loop_number + 1), 0, layer_height, input_params_tmp);
+                // ORCA: onion the real region (inside the outer wall) so the remaining walls follow the actual
+                // geometry, then cut away the parts over the top surface. Re-onioning the non-top complement
+                // instead - the fallback when there is no top fill - walls the top/non-top interface and rings
+                // top-surface islands with inner walls that don't exist when the feature is disabled.
+                const bool     clip_walls_over_top = top_fill_replaces_inner_walls(*this->config);
+                const Polygons inner_region        = to_polygons(offset_ex(clip_walls_over_top ? infill_contour
+                                                                                               : diff_ex(infill_contour, top_expolygons),
+                                                                          wall_0_inset));
+                Arachne::WallToolPaths inner_wall_tool_paths(inner_region, perimeter_spacing, perimeter_spacing, coord_t(inner_loop_number + 1), 0, layer_height, input_params_tmp);
                 std::vector<Arachne::VariableWidthLines> inner_perimeters = inner_wall_tool_paths.getToolPaths();
 
-                // Recalculate indexes of inner perimeters before merging them.
-                if (!perimeters.empty()) {
-                    for (Arachne::VariableWidthLines &inner_perimeter : inner_perimeters) {
-                        if (inner_perimeter.empty())
-                            continue;
+                if (clip_walls_over_top) {
+                    Polygons kept_over_top;
+                    clip_inner_walls_over_top(inner_perimeters, top_expolygons, perimeter_width, kept_over_top);
+                    // Route the top fill around the walls kept despite grazing the top.
+                    if (! kept_over_top.empty())
+                        top_expolygons = diff_ex(top_expolygons, kept_over_top);
+                }
+
+                // Recalculate indexes of inner perimeters before merging them: they come after the single outer wall.
+                if (!perimeters.empty())
+                    for (Arachne::VariableWidthLines &inner_perimeter : inner_perimeters)
                         for (Arachne::ExtrusionLine &el : inner_perimeter)
                             ++el.inset_idx;
-                    }
-                }
 
                 perimeters.insert(perimeters.end(), inner_perimeters.begin(), inner_perimeters.end());
                 infill_contour = union_ex(top_expolygons, inner_wall_tool_paths.getInnerContour());

src/libslic3r/PlaceholderParser.cpp

@@ -1791,6 +1791,8 @@ namespace client
             // from UTF8 to UTF16 don't bail out.
             msg += boost::nowide::narrow(boost::nowide::widen(error_line));
             msg += '\n';
+            // The error dialog (MsgDialog.cpp) renders this excerpt monospaced. It recognizes a source
+            // line directly above a caret line of spaces and a single '^'.
             for (size_t i = 0; i < error_pos; ++ i)
                 msg += ' ';
             msg += "^\n";

src/libslic3r/Polyline.hpp

@@ -129,13 +129,13 @@ public:
     std::vector<PathFittingData> fitting_result;
     //BBS: simplify points by arc fitting
     void simplify_by_fitting_arc(double tolerance);
-    //BBS: 
+    void reset_to_linear_move();
+    //BBS:
     Polylines equally_spaced_lines(double distance) const;
 
 private:
     void append_fitting_result_after_append_points();
     void append_fitting_result_after_append_polyline(const Polyline& src);
-    void reset_to_linear_move();
     bool split_fitting_result_before_index(const size_t index, Point &new_endpoint, std::vector<PathFittingData>& data) const;
     bool split_fitting_result_after_index(const size_t index, Point &new_startpoint, std::vector<PathFittingData>& data) const;
 };

src/libslic3r/Preset.cpp

@@ -1037,6 +1037,7 @@ static std::vector<std::string> s_Preset_print_options{
     "fill_multiline",
     "gyroid_optimized",
     "sparse_infill_pattern",
+    "sparse_infill_smooth_factor",
     "lateral_lattice_angle_1",
     "lateral_lattice_angle_2",
     "infill_overhang_angle",
@@ -1090,7 +1091,7 @@ static std::vector<std::string> s_Preset_print_options{
     "top_surface_speed", "support_speed", "support_object_xy_distance", "support_object_first_layer_gap", "support_interface_speed",
     "bridge_speed", "internal_bridge_speed", "gap_infill_speed", "travel_speed", "travel_speed_z", "initial_layer_speed",
     "outer_wall_acceleration", "initial_layer_acceleration", "top_surface_acceleration", "default_acceleration", "skirt_type", "skirt_loops", "skirt_speed","min_skirt_length", "skirt_distance", "skirt_start_angle", "skirt_height","single_loop_draft_shield", "draft_shield",
-    "brim_width", "brim_object_gap", "brim_flow_ratio", "brim_use_efc_outline", "combine_brims", "brim_type", "brim_ears_max_angle", "brim_ears_detection_length", "enable_support", "support_type", "support_threshold_angle", "support_threshold_overlap","enforce_support_layers",
+    "brim_width", "brim_object_gap", "brim_flow_ratio", "brim_use_efc_outline", "combine_brims", "brim_type", "brim_ears_max_angle", "brim_ears_detection_length", "brim_ears_outer_only", "enable_support", "support_type", "support_threshold_angle", "support_threshold_overlap","enforce_support_layers",
     "raft_layers", "raft_first_layer_density", "raft_first_layer_expansion", "raft_contact_distance", "raft_expansion",
     "support_base_pattern", "support_base_pattern_spacing", "support_expansion", "support_style",
     // BBS
@@ -1203,7 +1204,7 @@ static std::vector<std::string> s_Preset_print_options{
     "post_process",
     "slicing_pipeline_plugin",
     "plugins",
-    "plugin_config_overrides",
+    "print_plugin_config_overrides",
     "process_change_extrusion_role_gcode",
     "min_length_factor",
     "wall_maximum_resolution",
@@ -1350,6 +1351,8 @@ static std::vector<std::string> s_Preset_filament_options {/*"filament_colour",
     "filament_retraction_length",
     "filament_retraction_minimum_travel",
     "filament_retraction_speed",
+    "filament_retract_length_toolchange",
+    "filament_retract_restart_extra_toolchange",
     "filament_wipe",
     "filament_z_hop",
     "filament_z_hop_types",
@@ -1378,7 +1381,7 @@ static std::vector<std::string> s_Preset_filament_options {/*"filament_colour",
     "filament_preheat_temperature_delta", "filament_retract_length_nc",
     "filament_change_length_nc", "filament_prime_volume", "filament_prime_volume_nc",
     "long_retractions_when_ec", "retraction_distances_when_ec",
-    "plugin_config_overrides",
+    "filament_plugin_config_overrides",
     //ams chamber
     "filament_dev_ams_drying_ams_limitations", "filament_dev_ams_drying_temperature", "filament_dev_ams_drying_time", "filament_dev_ams_drying_heat_distortion_temperature",
     "filament_dev_chamber_drying_bed_temperature", "filament_dev_chamber_drying_time",
@@ -1403,7 +1406,7 @@ static std::vector<std::string> s_Preset_machine_limits_options {
 static std::vector<std::string> s_Preset_printer_options {
     "printer_technology",
     "printable_area", "extruder_printable_area", "support_parallel_printheads", "parallel_printheads_count", "parallel_printheads_bed_exclude_areas", "bed_exclude_area","bed_custom_texture", "bed_custom_model", "gcode_flavor",
-    "fan_kickstart", "part_cooling_fan_min_pwm", "fan_speedup_time", "fan_speedup_overhangs",
+     "gcode_skip_config_block", "fan_kickstart", "part_cooling_fan_min_pwm", "fan_speedup_time", "fan_speedup_overhangs",
     "single_extruder_multi_material", "manual_filament_change", "file_start_gcode", "machine_start_gcode", "machine_end_gcode", "before_layer_change_gcode", "printing_by_object_gcode", "layer_change_gcode", "time_lapse_gcode", "wrapping_detection_gcode", "change_filament_gcode", "change_extrusion_role_gcode",
     "printer_model", "printer_variant", "printer_extruder_id", "printer_extruder_variant", "extruder_variant_list", "default_nozzle_volume_type",
     "printable_height", "extruder_printable_height", "extruder_clearance_radius", "extruder_clearance_height_to_lid", "extruder_clearance_height_to_rod",
@@ -1420,7 +1423,7 @@ static std::vector<std::string> s_Preset_printer_options {
     "use_relative_e_distances", "extruder_type", "use_firmware_retraction", "printer_notes",
     "grab_length", "support_object_skip_flush", "physical_extruder_map",
     "cooling_tube_retraction",
-    "cooling_tube_length", "high_current_on_filament_swap", "parking_pos_retraction", "extra_loading_move", "wipe_tower_type", "purge_in_prime_tower", "enable_filament_ramming", "tool_change_on_wipe_tower",
+    "cooling_tube_length", "high_current_on_filament_swap", "parking_pos_retraction", "extra_loading_move", "wipe_tower_type", "purge_in_prime_tower", "enable_filament_ramming", "tool_change_on_wipe_tower", "wait_for_temp_on_wipe_tower",
     "z_offset",
     "disable_m73", "preferred_orientation", "emit_machine_limits_to_gcode", "pellet_modded_printer", "support_multi_bed_types", "use_3mf", "default_bed_type", "bed_mesh_min","bed_mesh_max","bed_mesh_probe_distance", "adaptive_bed_mesh_margin", "enable_long_retraction_when_cut","long_retractions_when_cut","retraction_distances_when_cut",
     "bed_temperature_formula", "nozzle_flush_dataset",
@@ -1430,7 +1433,7 @@ static std::vector<std::string> s_Preset_printer_options {
     // Fast-purge printer flag + device/firmware-facing per-variant extruder-change
     // deretraction speed (unconsumed by the slicer; carried by H2D/A2L/X2D/P2S machine profiles).
     "support_fast_purge_mode", "deretract_speed_extruder_change",
-    "plugin_config_overrides"
+    "printer_plugin_config_overrides"
     };
 
 static std::vector<std::string> s_Preset_sla_print_options {
@@ -1542,6 +1545,15 @@ const std::vector<std::string>& Preset::printer_options()
     return s_opts;
 }
 
+const char* Preset::plugin_overrides_key(Type type)
+{
+    switch (type) {
+    case TYPE_PRINTER:  return "printer_plugin_config_overrides";
+    case TYPE_FILAMENT: return "filament_plugin_config_overrides";
+    default:            return "print_plugin_config_overrides";
+    }
+}
+
 PresetCollection::PresetCollection(Preset::Type type, const std::vector<std::string> &keys, const Slic3r::StaticPrintConfig &defaults, const std::string &default_name) :
     m_type(type),
     m_edited_preset(type, "", false),
@@ -3774,12 +3786,14 @@ void PresetCollection::update_library_profile_excluded_from()
     }
 
     // Check all presets that has the same alias as the filament presets with empty compatible_printers in Orca Filament Library.
+    // A printer specific profile supersedes the generic one, no matter whether it lives in a vendor bundle or in the
+    // library itself.
     for (const Preset& preset : m_presets) {
-        if (preset.vendor == nullptr || preset.vendor->name == PresetBundle::ORCA_FILAMENT_LIBRARY)
+        if (preset.vendor == nullptr)
             continue;
 
         const auto* compatible_printers = dynamic_cast<const ConfigOptionStrings*>(preset.config.option("compatible_printers"));
-        // All profiles in concrete vendor profile shouldn't have empty compatible_printers, but here we check it for safety.
+        // Profiles with empty compatible_printers are the generic ones, they never supersede anything.
         if (compatible_printers == nullptr || compatible_printers->values.empty())
             continue;
         auto itr = excluded_froms.find(preset.alias);

src/libslic3r/Preset.hpp

@@ -407,6 +407,11 @@ public:
     // Printer machine limits, those are contained in printer_options().
     static const std::vector<std::string>&  machine_limits_options();
 
+    // Option key holding this preset type's plugin capability overrides. Each type has its own key so
+    // the values survive the merge into a single full config; print is the fallback for the types with
+    // no plugin-backed options.
+    static const char*                      plugin_overrides_key(Type type);
+
     static const std::vector<std::string>&  sla_printer_options();
     static const std::vector<std::string>&  sla_material_options();
     static const std::vector<std::string>&  sla_print_options();

src/libslic3r/PresetBundle.cpp

@@ -5378,7 +5378,7 @@ void PresetBundle::update_multi_material_filament_presets(size_t to_delete_filam
         f_multiplier.resize(nozzle_nums, 1.f);
     }
 
-    if ( (num_filaments * num_filaments) != size_t(old_matrix.size() / old_nozzle_nums) ) {
+    if (old_matrix.size() != num_filaments * num_filaments * nozzle_nums) {
         // First verify if purging volumes presets for each extruder matches number of extruders
         std::vector<double>& filaments = this->project_config.option<ConfigOptionFloats>("flush_volumes_vector")->values;
         while (filaments.size() < 2* num_filaments) {

src/libslic3r/Print.cpp

@@ -282,9 +282,18 @@ bool Print::invalidate_state_by_config_options(const ConfigOptionResolver & /* n
             || opt_key == "wipe_tower_x"
             || opt_key == "wipe_tower_y"
             || opt_key == "wipe_tower_rotation_angle") {
+            // The tower gcode itself is position-independent (position and rotation are applied
+            // at export), except that the wait_for_temp_on_wipe_tower park bakes a bed-relative
+            // side choice into it (WipeTower2::toolchange_Change) — regenerate it when the tower
+            // moves. Gating on the old config is safe: both inputs of wait_for_temp_enabled
+            // invalidate psWipeTower themselves when they are part of the same diff.
+            if ((opt_key == "wipe_tower_x" || opt_key == "wipe_tower_y" || opt_key == "wipe_tower_rotation_angle")
+                && WipeTower2::wait_for_temp_enabled(m_config))
+                steps.emplace_back(psWipeTower);
             steps.emplace_back(psSkirtBrim);
         } else if (
                opt_key == "slicing_pipeline_plugin"
+            || opt_key == "print_plugin_config_overrides"
             || opt_key == "initial_layer_print_height"
             || opt_key == "nozzle_diameter"
             || opt_key == "filament_shrink"
@@ -381,6 +390,7 @@ bool Print::invalidate_state_by_config_options(const ConfigOptionResolver & /* n
             || opt_key == "wiping_volumes_extruders"
             || opt_key == "enable_filament_ramming"
             || opt_key == "tool_change_on_wipe_tower"
+            || opt_key == "wait_for_temp_on_wipe_tower"
             || opt_key == "purge_in_prime_tower"
             || opt_key == "z_offset"
             || opt_key == "support_multi_bed_types"
@@ -1038,13 +1048,14 @@ static StringObjectException layered_print_cleareance_valid(const Print &print,
             wipe_tower_convex_hull.points.emplace_back(scale_(x + width), scale_(y));
             wipe_tower_convex_hull.points.emplace_back(scale_(x + width), scale_(y + depth));
             wipe_tower_convex_hull.points.emplace_back(scale_(x), scale_(y + depth));
-            wipe_tower_convex_hull.rotate(a);
+            wipe_tower_convex_hull.rotate(Geometry::deg2rad(a), Point(scale_(x), scale_(y)));
             convex_hulls_temp.push_back(wipe_tower_convex_hull);
         } else {
             //here, wipe_tower_polygon is not always convex.
             Polygon wipe_tower_polygon;
             if (print.wipe_tower_data().wipe_tower_mesh_data)
                 wipe_tower_polygon = print.wipe_tower_data().wipe_tower_mesh_data->bottom;
+            wipe_tower_polygon.rotate(Geometry::deg2rad(a));
             wipe_tower_polygon.translate(Point(scale_(x), scale_(y)));
             convex_hulls_temp.push_back(wipe_tower_polygon);
         }
@@ -1063,6 +1074,22 @@ static StringObjectException layered_print_cleareance_valid(const Print &print,
     if (print_config.enable_wrapping_detection.value && !intersection({wrapping_poly}, convex_hulls_temp).empty()) {
         return {L("Prime Tower") + L(" is too close to clumping detection area, and collisions will be caused.\n")};
     }
+    // Skip the containment check for towers that will never be printed (single-filament
+    // prints without smooth timelapse keep the config's tower position but emit nothing).
+    // Pre-generation only the body square is tested — the auto-brim estimate can overshoot
+    // the generated brim by several mm and must not hard-fail a print that physically fits.
+    // Post-generation the mesh bottom already includes the real brim, so the exact
+    // footprint is tested.
+    if (filaments_count > 1 || print.enable_timelapse_print()) {
+        // The shared printable polygon is plate-local, while the tower polygons above are
+        // already shifted by the plate origin.
+        Polygons    printable_polys = print.get_extruder_shared_printable_polygon();
+        const Point plate_shift(scale_(plate_origin.x()), scale_(plate_origin.y()));
+        for (Polygon &p : printable_polys)
+            p.translate(plate_shift);
+        if (!diff(convex_hulls_temp, printable_polys).empty())
+            return {L("Prime Tower") + L(" is partially outside the printable area, and it cannot be printed.\n")};
+    }
     return {};
 }
 
@@ -3408,7 +3435,11 @@ void Print::update_filament_maps_to_config(std::vector<int> f_maps, std::vector<
             }
             else if ((extruder_volume_type_count > extruder_count) && (m_config.filament_volume_map.values.size() > index))
                 nozzle_volume_type = (NozzleVolumeType)(m_config.filament_volume_map.values[index]);
-            m_config.filament_map_2.values[index] = m_ori_full_print_config.get_index_for_extruder(f_maps[index], "print_extruder_id", extruder_type, nozzle_volume_type, "print_extruder_variant");
+            // Orca: when the process variant columns cannot be matched (degenerate
+            // print_extruder_id), key the override by plain extruder index like the seeding
+            // above instead of poisoning the map with -1.
+            int slot_index = m_ori_full_print_config.get_index_for_extruder(f_maps[index], "print_extruder_id", extruder_type, nozzle_volume_type, "print_extruder_variant");
+            m_config.filament_map_2.values[index] = slot_index >= 0 ? slot_index : f_maps[index] - 1;
         }
 
         m_full_print_config = m_ori_full_print_config;
@@ -3913,6 +3944,12 @@ const WipeTowerData &Print::wipe_tower_data(size_t filaments_cnt) const
         double volume = wipe_volume * filament_depth_count;
         if (m_config.nozzle_diameter.values.size() == 2) volume += filament_change_volume * (int) (filaments_cnt / 2);
 
+        // Sizing should take into account currently set wiping volumes.
+        // For a long time, the initial preview would just use 900/width per toolchange (15mm on a 60mm wide tower)
+        // and it worked well enough. Let's try to do slightly better by accounting for the purging volumes.
+        const bool semm_flush = m_config.purge_in_prime_tower && m_config.single_extruder_multi_material;
+        if (semm_flush) volume = WipeTower2::estimate_semm_flush_volume(m_config, filaments_cnt);
+
         if (m_config.wipe_tower_wall_type.value == WipeTowerWallType::wtwRib) {
             double depth = std::sqrt(volume / layer_height * extra_spacing);
             if (need_wipe_tower || filaments_cnt > 1) {
@@ -3924,30 +3961,16 @@ const WipeTowerData &Print::wipe_tower_data(size_t filaments_cnt) const
             }
         }
         else {
-        double width        = m_config.prime_tower_width;
-        if (m_config.purge_in_prime_tower && m_config.single_extruder_multi_material) {
-            // Calculating depth should take into account currently set wiping volumes.
-            // For a long time, the initial preview would just use 900/width per toolchange (15mm on a 60mm wide tower)
-            // and it worked well enough. Let's try to do slightly better by accounting for the purging volumes.
-            std::vector<std::vector<float>> wipe_volumes = WipeTower2::extract_wipe_volumes(m_config);
-            std::vector<float>              max_wipe_volumes;
-            for (const std::vector<float> &v : wipe_volumes)
-                max_wipe_volumes.emplace_back(*std::max_element(v.begin(), v.end()));
-            float maximum = std::accumulate(max_wipe_volumes.begin(), max_wipe_volumes.end(), 0.f);
-            maximum       = maximum * filaments_cnt / max_wipe_volumes.size();
-            
-            // Orca: it's overshooting a bit, so let's reduce it a bit
-            maximum *= 0.6; 
-            const_cast<Print *>(this)->m_wipe_tower_data.depth = maximum / (layer_height * width);
-        } else {
-            double depth = volume / (layer_height * width) * extra_spacing;
-            if (need_wipe_tower || m_wipe_tower_data.depth > EPSILON) {
+            double width = m_config.prime_tower_width;
+            double depth = volume / (layer_height * width);
+            // The flush volumes already hold the spacing between wipes.
+            if (!semm_flush) depth *= extra_spacing;
+            if (need_wipe_tower || depth > EPSILON) {
                 float min_wipe_tower_depth = WipeTower::get_limit_depth_by_height(max_height);
                 depth = std::max((double) min_wipe_tower_depth, depth);
             }
             const_cast<Print *>(this)->m_wipe_tower_data.depth = depth;
-        }
-        const_cast<Print *>(this)->m_wipe_tower_data.brim_width = m_config.prime_tower_brim_width;
+            const_cast<Print *>(this)->m_wipe_tower_data.brim_width = m_config.prime_tower_brim_width;
         }
         if (m_config.prime_tower_brim_width < 0) const_cast<Print *>(this)->m_wipe_tower_data.brim_width = WipeTower::get_auto_brim_by_height(max_height);
     }
@@ -4016,10 +4039,33 @@ void Print::_make_wipe_tower()
         // in BBL machine, wipe tower is only use to prime extruder. So just use a global wipe volume.
         WipeTower wipe_tower(m_config, m_plate_index, m_origin, m_wipe_tower_data.tool_ordering.first_extruder(),
                              m_wipe_tower_data.tool_ordering.empty() ? 0.f : m_wipe_tower_data.tool_ordering.back().print_z, m_wipe_tower_data.tool_ordering.all_extruders());
+        // Orca: the tower's first-layer flow follows the user's first-layer flow ratio (BBS reads
+        // its initial_layer_flow_ratio here — STUDIO-14254; first_layer_flow_ratio is Orca's analog,
+        // default 1.0 in both). Honor the set_other_flow_ratios gate that governs the option
+        // everywhere else.
+        wipe_tower.set_first_layer_flow_ratio(m_default_object_config.set_other_flow_ratios
+                                                  ? float(m_default_region_config.first_layer_flow_ratio)
+                                                  : 1.f);
         wipe_tower.set_has_tpu_filament(this->has_tpu_filament());
-        wipe_tower.set_filament_map(this->get_filament_maps());
-        // Vortek H2C: pass nozzle-level map for carousel rotation detection in tool_change_new()
-        wipe_tower.set_filament_nozzle_map(this->get_filament_nozzle_maps());
+        // Per-layer filament->nozzle grouping. sort_and_build_data() above publishes it on the Print
+        // for by-layer prints; by-object prints publish only later (psSkirtBrim), so fall back to the
+        // ToolOrdering's own copy there. set_extruder() below dereferences it, so it must be set first.
+        auto print_group_result = get_layered_nozzle_group_result();
+        const MultiNozzleUtils::LayeredNozzleGroupResult &nozzle_group_result =
+            print_group_result ? *print_group_result : m_wipe_tower_data.tool_ordering.get_layered_nozzle_group_result();
+        wipe_tower.set_nozzle_group_result(nozzle_group_result);
+        {
+            // Orca: acceleration options are object-scope (PrintConfig members in BBS), so resolve
+            // the per-variant columns here; initial_layer_travel_acceleration is FloatOrPercent
+            // over travel_acceleration and needs the full config to resolve.
+            std::vector<double> first_layer_travel_accels;
+            for (size_t i = 0; i < m_config.initial_layer_travel_acceleration.values.size(); ++i)
+                first_layer_travel_accels.emplace_back(m_full_print_config.get_abs_value_at("initial_layer_travel_acceleration", i));
+            wipe_tower.set_accelerations(m_default_object_config.default_acceleration.values,
+                                         m_default_object_config.initial_layer_acceleration.values,
+                                         m_default_object_config.travel_acceleration.values,
+                                         first_layer_travel_accels);
+        }
         // Feed the has_filament_switcher device flag (develop-only dynamic key, read defensively from
         // the full config — no shipping profile sets it) and the shared printable bed used by the PETG
         // pre-extrusion offset clamp. Both are inert unless has_filament_switcher is set.
@@ -4055,27 +4101,19 @@ void Print::_make_wipe_tower()
             multi_extruder_flush.emplace_back(wipe_volumes);
         }
 
-        // Use NozzleStatusRecorder for per-carousel-slot tracking (BBS pattern).
-        // The original Orca code tracked per-extruder (2 slots), which collapsed all
-        // carousel filaments into one slot and caused massive redundant AMS flushing.
-        auto group_result = get_layered_nozzle_group_result();
+        // Per-carousel-slot purge tracking via NozzleStatusRecorder (BBS pattern); the layered
+        // group result set on the tower above resolves each filament to its nozzle slot per layer.
         MultiNozzleUtils::NozzleStatusRecorder nozzle_recorder;
-        // Fallback (group_result == null) per-physical-nozzle tracking, matching the original
-        // pre-port behavior: remembers the last filament loaded in each physical nozzle slot.
-        std::vector<unsigned int> nozzle_cur_filament_ids(nozzle_nums, (unsigned int) -1);
 
         std::vector<int>filament_maps = get_filament_maps();
         int layer_idx = -1;
 
         unsigned int current_filament_id = m_wipe_tower_data.tool_ordering.first_extruder();
         // Initialize NozzleStatusRecorder with the first filament's carousel slot
-        if (group_result) {
-            auto nozzle = group_result->get_nozzle_for_filament(current_filament_id, layer_idx);
+        {
+            auto nozzle = nozzle_group_result.get_nozzle_for_filament(current_filament_id, layer_idx);
             if (nozzle)
                 nozzle_recorder.set_nozzle_status(nozzle->group_id, current_filament_id, nozzle->extruder_id);
-        } else {
-            size_t cur_nozzle_id = filament_maps[current_filament_id] - 1;
-            nozzle_cur_filament_ids[cur_nozzle_id] = current_filament_id;
         }
 
         for (auto& layer_tools : m_wipe_tower_data.tool_ordering.layer_tools()) { // for all layers
@@ -4094,8 +4132,8 @@ void Print::_make_wipe_tower()
                 float volume_to_purge = 0;
 
                 // Per-carousel-slot purge tracking via NozzleStatusRecorder
-                if (group_result) {
-                    auto nozzle_info = group_result->get_nozzle_for_filament(filament_id, layer_idx);
+                {
+                    auto nozzle_info = nozzle_group_result.get_nozzle_for_filament(filament_id, layer_idx);
                     if (nozzle_info) {
                         int extruder_id = nozzle_info->extruder_id;
                         int nozzle_id   = nozzle_info->group_id;
@@ -4114,22 +4152,6 @@ void Print::_make_wipe_tower()
                         }
                         nozzle_recorder.set_nozzle_status(nozzle_id, filament_id, extruder_id);
                     }
-                } else {
-                    // Fallback: original Orca per-physical-nozzle path (non-carousel printers).
-                    // Flush source is the last filament that occupied THIS nozzle, guarded so the
-                    // first use of a nozzle incurs no flush.
-                    int nozzle_id = filament_maps[filament_id] - 1;
-                    unsigned int pre_filament_id = nozzle_cur_filament_ids[nozzle_id];
-                    if (pre_filament_id != (unsigned int) -1 && pre_filament_id != filament_id) {
-                        volume_to_purge = multi_extruder_flush[nozzle_id][pre_filament_id][filament_id];
-                        float flush_multiplier = (m_config.prime_volume_mode == PrimeVolumeMode::pvmFast)
-                            ? m_config.flush_multiplier_fast.get_at(nozzle_id)
-                            : m_config.flush_multiplier.get_at(nozzle_id);
-                        volume_to_purge *= flush_multiplier;
-                        volume_to_purge = layer_tools.wiping_extrusions().mark_wiping_extrusions(
-                            *this, current_filament_id, filament_id, volume_to_purge);
-                    }
-                    nozzle_cur_filament_ids[nozzle_id] = filament_id;
                 }
 
                 //During the filament change, the extruder will extrude an extra length of grab_length for the corresponding detection, so the purge can reduce this length.
@@ -4137,29 +4159,21 @@ void Print::_make_wipe_tower()
                 float grab_purge_volume = m_config.grab_length.get_at(grab_extruder_id) * 2.4; //(diameter/2)^2*PI=2.4
                 volume_to_purge = std::max(0.f, volume_to_purge - grab_purge_volume);
 
-                // Select prime volume per-filament: nozzle change (carousel rotation) uses
-                // filament_prime_volume_nc, filament change (same nozzle slot) uses filament_prime_volume.
+                // Prime volume per-filament: the tower now picks extruder-change vs nozzle-change
+                // (carousel) internally per plan layer, so pass both candidates (BBS pattern).
                 float wipe_volume_ec = filament_id < m_config.filament_prime_volume.values.size()
                     ? m_config.filament_prime_volume.values[filament_id]
                     : (float) m_config.prime_volume;
                 float wipe_volume_nc = filament_id < m_config.filament_prime_volume_nc.values.size()
                     ? m_config.filament_prime_volume_nc.values[filament_id]
                     : (float) m_config.prime_volume;
-
-                float prime_volume = wipe_volume_ec;
-                if (group_result) {
-                    bool is_nozzle_change = group_result->are_filaments_same_extruder(current_filament_id, filament_id, layer_idx) &&
-                                           !group_result->are_filaments_same_nozzle(current_filament_id, filament_id, layer_idx);
-                    if (is_nozzle_change) {
-                        prime_volume = wipe_volume_nc;
-                    }
-                }
                 if (m_config.prime_volume_mode == PrimeVolumeMode::pvmSaving) {
-                    prime_volume = 15.f;
+                    wipe_volume_ec = 15.f;
+                    wipe_volume_nc = 15.f;
                 }
 
                 wipe_tower.plan_toolchange((float)layer_tools.print_z, (float)layer_tools.wipe_tower_layer_height, current_filament_id, filament_id,
-                    prime_volume, volume_to_purge);
+                    wipe_volume_ec, wipe_volume_nc, volume_to_purge);
                 current_filament_id = filament_id;
             }
             layer_tools.wiping_extrusions().ensure_perimeters_infills_order(*this);
@@ -4337,7 +4351,12 @@ void Print::_make_wipe_tower()
                                          wipe_tower.get_rib_width(), wipe_tower.get_rib_length(),
                                          config().wipe_tower_fillet_wall.value);
         const Vec3d origin                      = Vec3d::Zero();
-        m_fake_wipe_tower.set_fake_extrusion_data(wipe_tower.position(), wipe_tower.width(), wipe_tower.get_wipe_tower_height(),
+        // FakeWipeTower::pos is a bed-frame translation applied after rotation
+        // (getFakeExtrusionPathsFromWipeTower2 rotates about the local origin), so the
+        // tower-local rib offset must be rotated into the bed frame first.
+        m_fake_wipe_tower.rib_offset = Eigen::Rotation2Df(Geometry::deg2rad((float)config().wipe_tower_rotation_angle.value)) *
+                                       wipe_tower.get_rib_offset();
+        m_fake_wipe_tower.set_fake_extrusion_data(wipe_tower.position() + m_fake_wipe_tower.rib_offset, wipe_tower.width(), wipe_tower.get_wipe_tower_height(),
                                                   config().initial_layer_print_height, m_wipe_tower_data.depth,
                                                   m_wipe_tower_data.z_and_depth_pairs, m_wipe_tower_data.brim_width,
                                                   config().wipe_tower_rotation_angle, config().wipe_tower_cone_angle,

src/libslic3r/PrintApply.cpp

@@ -559,9 +559,11 @@ static inline bool model_volume_solid_or_modifier(const ModelVolume &mv)
 
 static inline Transform3f trafo_for_bbox(const Transform3d &object_trafo, const Transform3d &volume_trafo)
 {
-    Transform3d m = object_trafo * volume_trafo;
-    m.translation().x() = 0.;
-    m.translation().y() = 0.;
+    // Orca: Keep the volume's local XY offset for multipart overlap checks, but remove the object's bed placement.
+    Transform3d object_trafo_local = object_trafo;
+    object_trafo_local.translation().x() = 0.;
+    object_trafo_local.translation().y() = 0.;
+    Transform3d m = object_trafo_local * volume_trafo;
     return m.cast<float>();
 }
 
@@ -1355,7 +1357,11 @@ Print::ApplyStatus Print::apply(const Model &model, DynamicPrintConfig new_full_
         if ((extruder_volume_type_count > extruder_count) && opt_filament_volume_maps
             && opt_filament_volume_maps->values.size() == filament_maps.size())
             nozzle_volume_type = (NozzleVolumeType)(opt_filament_volume_maps->values[index]);
-        m_config.filament_map_2.values[index] = new_full_config.get_index_for_extruder(filament_maps[index], "print_extruder_id", extruder_type, nozzle_volume_type, "print_extruder_variant");
+        // Orca: when the process variant columns cannot be matched (degenerate
+        // print_extruder_id), key the override by plain extruder index like the seeding
+        // above instead of poisoning the map with -1.
+        int slot_index = new_full_config.get_index_for_extruder(filament_maps[index], "print_extruder_id", extruder_type, nozzle_volume_type, "print_extruder_variant");
+        m_config.filament_map_2.values[index] = slot_index >= 0 ? slot_index : filament_maps[index] - 1;
     }
 
     // Do not use the ApplyStatus as we will use the max function when updating apply_status.
@@ -1411,6 +1417,16 @@ Print::ApplyStatus Print::apply(const Model &model, DynamicPrintConfig new_full_
             num_extruders_changed  = true;
         }
     }
+    else if (! print_diff.empty()) {
+        // Orca: m_config can diverge from an unchanged full config (e.g. the in-slice retract
+        // override recompute writing different values than the apply-time computation). The
+        // invalidation above already fired for print_diff, so repair m_config here as well;
+        // otherwise the divergence is never corrected and every subsequent apply of the same
+        // config invalidates the result again, forever.
+        m_placeholder_parser.apply_config(filament_overrides);
+        m_config.apply_only(new_full_config, print_diff, true);
+        m_config.apply(filament_overrides);
+    }
 
     ModelObjectStatusDB model_object_status_db;
 

src/libslic3r/PrintConfig.cpp

@@ -72,6 +72,8 @@ const std::vector<std::string> filament_extruder_override_keys = {
     "filament_deretraction_speed",
     "filament_retract_restart_extra",  //not in filament_options_with_variant, added on 20250816
     "filament_retraction_minimum_travel",
+    "filament_retract_length_toolchange",
+    "filament_retract_restart_extra_toolchange",
     // BBS: floats
     "filament_wipe_distance",
     // bools
@@ -331,6 +333,8 @@ CONFIG_OPTION_ENUM_DEFINE_STATIC_MAPS(PrintSequence)
 static t_config_enum_values s_keys_map_PrintOrder{
     { "default",     int(PrintOrder::Default) },
     { "as_obj_list", int(PrintOrder::AsObjectList)},
+    { "best_of",       int(PrintOrder::BestOfStrategies)},
+    { "snake", int(PrintOrder::Snake)},
 };
 CONFIG_OPTION_ENUM_DEFINE_STATIC_MAPS(PrintOrder)
 
@@ -1081,16 +1085,21 @@ void PrintConfigDef::init_common_params()
         def->set_default_value(new ConfigOptionString());
     }
 
-    def = this->add("plugin_config_overrides", coString);
-    def->label = L("Capabilities");
-    def->tooltip = L("Configuration for the plugin capabilities this preset uses, overriding the global "
-                     "Capabilities configuration. Stored as a raw JSON array and edited through the dialog "
-                     "behind the button, never typed in directly.");
-    // Never shown as a text field: GUIType::plugin_config renders a button that opens PluginsConfigDialog.
-    def->gui_type = ConfigOptionDef::GUIType::plugin_config;
-    def->mode = comAdvanced;
-    def->cli = ConfigOptionDef::nocli;
-    def->set_default_value(new ConfigOptionString(""));
+    // One key per preset type (Preset::plugin_overrides_key), so the print, printer and filament
+    // overrides don't clobber each other when the presets merge into one full config. No handle_legacy
+    // migration from the shared "plugin_config_overrides" they replace: it only ever shipped in
+    // nightlies. Never a text field — GUIType::plugin_config renders a button opening PluginsConfigDialog.
+    for (const char* key : {"print_plugin_config_overrides", "printer_plugin_config_overrides", "filament_plugin_config_overrides"}) {
+        def = this->add(key, coString);
+        def->label = L("Capabilities");
+        def->tooltip = L("Configuration for the plugin capabilities this preset uses, overriding the global "
+                         "Capabilities configuration. Stored as a raw JSON array and edited through the dialog "
+                         "behind the button, never typed in directly.");
+        def->gui_type = ConfigOptionDef::GUIType::plugin_config;
+        def->mode = comAdvanced;
+        def->cli = ConfigOptionDef::nocli;
+        def->set_default_value(new ConfigOptionString(""));
+    }
 }
 
 void PrintConfigDef::init_fff_params()
@@ -1930,6 +1939,13 @@ void PrintConfigDef::init_fff_params()
     def->mode = comAdvanced;
     def->set_default_value(new ConfigOptionFloat(1));
 
+    def = this->add("brim_ears_outer_only", coBool);
+    def->label = L("Brim ears outer only");
+    def->category = L("Support");
+    def->tooltip = L("Generate mouse ears only on the outer contour of the model, excluding holes and enclosed sections.");
+    def->mode = comAdvanced;
+    def->set_default_value(new ConfigOptionBool(false));
+
     def = this->add("compatible_printers", coStrings);
     def->label = L("Select printers");
     def->mode = comAdvanced;
@@ -1994,12 +2010,30 @@ void PrintConfigDef::init_fff_params()
 
     def = this->add("print_order", coEnum);
     def->label = L("Intra-layer order");
-    def->tooltip = L("Print order within a single layer.");
+    def->tooltip = L("Order in which object instances are visited within a single layer, which controls how much "
+                     "travel is spent moving between them.\n\n"
+                     "Default: nearest-neighbor chaining, refined with 2-opt and crossing removal. A good general "
+                     "choice.\n"
+                     "As object list: instances are printed in the same order as the object list, without any path "
+                     "optimization. Use it when you need a predictable, manually controlled order.\n"
+                     "Best of all (shortest path): every strategy is evaluated and the shortest one is used. The "
+                     "object instance order is decided once for the whole print, while the ordering of individual "
+                     "islands is decided per layer, so different layers may end up using different strategies. "
+                     "Slightly slower to slice.\n"
+                     "Snake: serpentine row-by-row traversal, refined with 2-opt. Well suited to regular grids of "
+                     "many small parts.\n\n"
+                     "With multiple filaments or tools in the same layer, minimizing tool changes takes priority: "
+                     "objects are grouped by filament first and this setting only orders the instances within each "
+                     "filament group, so the overall sequence may not look like the shortest path across the plate.");
     def->enum_keys_map = &ConfigOptionEnum<PrintOrder>::get_enum_values();
     def->enum_values.push_back("default");
     def->enum_values.push_back("as_obj_list");
+    def->enum_values.push_back("best_of");
+    def->enum_values.push_back("snake");
     def->enum_labels.push_back(L("Default"));
     def->enum_labels.push_back(L("As object list"));
+    def->enum_labels.push_back(L("Best of all (shortest path)"));
+    def->enum_labels.push_back(L("Snake"));
     def->mode = comAdvanced;
     def->set_default_value(new ConfigOptionEnum<PrintOrder>(PrintOrder::Default));
 
@@ -3432,6 +3466,18 @@ void PrintConfigDef::init_fff_params()
     def->enum_labels.push_back(L("Octagram Spiral"));
     def->set_default_value(new ConfigOptionEnum<InfillPattern>(ipCrossHatch));
 
+    def = this->add("sparse_infill_smooth_factor", coPercent);
+    def->label = L("Sparse infill smooth factor");
+    def->category = L("Strength");
+    def->tooltip = L("Controls how strongly sparse infill corners are rounded. 0% keeps the original right-angle path, "
+                     "while 100% produces the largest possible curves between adjacent infill lines. "
+                     "Currently applies only to the Hilbert Curve.");
+    def->sidetext = "%";
+    def->min = 0;
+    def->max = 100;
+    def->mode = comAdvanced;
+    def->set_default_value(new ConfigOptionPercent(0));
+
     def = this->add("top_surface_acceleration", coFloats);
     def->label = L("Top surface");
     def->category = L("Speed");
@@ -4215,6 +4261,15 @@ void PrintConfigDef::init_fff_params()
     def->readonly = false;
     def->set_default_value(new ConfigOptionEnum<GCodeFlavor>(gcfMarlinLegacy));
 
+    def = this->add("gcode_skip_config_block", coBool);
+    def->label = L("Skip G-code config block");
+    def->tooltip = L("Do not write the CONFIG_BLOCK (slicer configuration key/value pairs) into the G-code file. "
+                   "This can help with printers whose firmware crashes when parsing these comment lines "
+                   "(e.g. Anycubic go-klipper). Note: the G-code file will no longer contain slicer settings, "
+                   "so importing it back into OrcaSlicer will not restore the configuration.");
+    def->mode = comAdvanced;
+    def->set_default_value(new ConfigOptionBool(false));
+
     def          = this->add("pellet_modded_printer", coBool);
     def->label   = L("Pellet Modded Printer");
     def->tooltip = L("Enable this option if your printer uses pellets instead of filaments.");
@@ -4248,7 +4303,7 @@ void PrintConfigDef::init_fff_params()
                    "slow down.");
     def->mode = comAdvanced;
     def->set_default_value(new ConfigOptionBool(0));
-    
+
     //BBS
     def = this->add("infill_combination", coBool);
     def->label = L("Infill combination");
@@ -5624,6 +5679,7 @@ void PrintConfigDef::init_fff_params()
     // Orca:
     def = this->add("retract_after_wipe", coPercents);
     def->label = L("Retract amount after wipe");
+    // xgettext:no-c-format, no-boost-format
     def->tooltip = L("The length of fast retraction after wipe, relative to retraction length.\n"
                      "The value will be clamped by 100% minus the retract amount before the wipe value.");
     def->sidetext = "%";
@@ -5680,12 +5736,10 @@ void PrintConfigDef::init_fff_params()
     def->set_default_value(new ConfigOptionFloatsNullable{10});
 
     def = this->add("retract_length_toolchange", coFloats);
-    def->label = L("Length");
-    //def->full_label = L("Retraction Length (Toolchange)");
-    def->full_label = "Retraction Length (Toolchange)";
-    //def->tooltip = L("When retraction is triggered before changing tool, filament is pulled back "
-    //               "by the specified amount (the length is measured on raw filament, before it enters "
-    //               "the extruder).");
+    def->label = L("Retraction Length (Toolchange)");
+    def->tooltip = L("When retraction is triggered before changing tool, filament is pulled back "
+                  "by the specified amount (the length is measured on raw filament, before it enters "
+                  "the extruder).");
     def->sidetext = L("mm");	// millimeters, CIS languages need translation
     def->mode = comAdvanced;
     def->set_default_value(new ConfigOptionFloats { 10. });
@@ -5939,7 +5993,7 @@ void PrintConfigDef::init_fff_params()
     def->set_default_value(new ConfigOptionFloats { 0. });
 
     def = this->add("retract_restart_extra_toolchange", coFloats);
-    def->label = L("Extra length on restart");
+    def->label = L("Extra length on restart (Toolchange)");
     def->tooltip = L("When the retraction is compensated after changing tool, the extruder will push "
                   "this additional amount of filament.");
     def->sidetext = L("mm");	// millimeters, CIS languages need translation
@@ -6516,6 +6570,17 @@ void PrintConfigDef::init_fff_params()
     def->mode = comAdvanced;
     def->set_default_value(new ConfigOptionBool(false));
 
+    def = this->add("wait_for_temp_on_wipe_tower", coBool);
+    def->label = L("Wait for temperature on wipe tower");
+    def->tooltip = L("Pick up the new tool without waiting for it to reach printing temperature, travel to the wipe "
+                     "tower, and wait for the temperature there, right before purging. Ooze from the heat-up lands on "
+                     "the tower instead of the model, and the travel overlaps with the heating. "
+                     "Only relevant for multi-extruder (multi-toolhead) printers using a Type 2 wipe tower. "
+                     "The firmware or tool change macro must not wait for the temperature itself. "
+                     "When disabled, the temperature wait is issued right after the tool change command.");
+    def->mode = comAdvanced;
+    def->set_default_value(new ConfigOptionBool(false));
+
 
     def = this->add("wipe_tower_no_sparse_layers", coBool);
     def->label = L("No sparse layers (beta)");
@@ -8109,10 +8174,12 @@ void PrintConfigDef::init_extruder_option_keys()
         "long_retractions_when_cut",
         "retract_after_wipe",
         "retract_before_wipe",
+        "retract_length_toolchange",
         "retract_lift_above",
         "retract_lift_below",
         "retract_lift_enforce",
         "retract_restart_extra",
+        "retract_restart_extra_toolchange",
         "retract_when_changing_layer",
         "retraction_distances_when_cut",
         "retraction_length",
@@ -9200,6 +9267,8 @@ std::set<std::string> filament_options_with_variant = {
     "filament_retract_lift_below",
     "filament_retract_lift_enforce",
     "filament_retract_restart_extra",
+    "filament_retract_length_toolchange",
+    "filament_retract_restart_extra_toolchange",
     "filament_retraction_speed",
     "filament_deretraction_speed",
     "filament_retraction_minimum_travel",
@@ -10490,6 +10559,44 @@ int DynamicPrintConfig::get_extruder_nozzle_volume_count(int extruder_count, std
     return count;
 }
 
+// Orca: BBL system profiles ship full-width print_extruder_id/print_extruder_variant columns, but
+// custom multi-extruder printers only ever get the machine-scope columns synthesized for them (see
+// extend_extruder_variant); the process scope keeps the length-1 defaults, both in presets and in
+// 3mf project configs. Expanding with that degenerate map makes every per-extruder lookup fail, and
+// because both keys are themselves in print_options_with_variant, the expansion then latches a
+// full-width-but-wrong [1,1,...] map that also defeats the generated_extruder_id fallback in
+// get_index_for_extruder. Synthesize the process columns from the printer's extruder_variant_list
+// (same token walk as extend_extruder_variant) before expanding.
+static void ensure_process_variant_columns(DynamicPrintConfig &config, const DynamicPrintConfig &printer_config)
+{
+    auto id_opt      = dynamic_cast<ConfigOptionInts *>(config.option("print_extruder_id"));
+    auto variant_opt = dynamic_cast<ConfigOptionStrings *>(config.option("print_extruder_variant"));
+    auto list_opt    = dynamic_cast<const ConfigOptionStrings *>(printer_config.option("extruder_variant_list"));
+    if (!id_opt || !variant_opt || !list_opt)
+        return;
+    if (id_opt->values.size() != 1 || variant_opt->values.size() != 1)
+        return;
+
+    std::vector<int>         ids;
+    std::vector<std::string> variants;
+    for (int i = 0; i < int(list_opt->values.size()); ++i) {
+        std::vector<std::string> tokens;
+        boost::split(tokens, list_opt->get_at(i), boost::is_any_of(","), boost::token_compress_on);
+        for (std::string &token : tokens) {
+            boost::trim(token);
+            if (token.empty())
+                continue;
+            ids.push_back(i + 1);
+            variants.push_back(token);
+        }
+    }
+    // A single column is the legitimate single-extruder layout, not a degenerate one.
+    if (ids.size() <= 1)
+        return;
+    id_opt->values      = std::move(ids);
+    variant_opt->values = std::move(variants);
+}
+
 std::vector<int> DynamicPrintConfig::update_values_to_printer_extruders(DynamicPrintConfig& printer_config, int extruder_count, int extruder_nozzle_volume_count, std::vector<std::vector<NozzleVolumeType>>& nv_types,
     std::set<std::string>& key_set, std::string id_name, std::string variant_name, unsigned int stride, unsigned int extruder_id, NozzleVolumeType filament_nvt)
 {
@@ -10531,6 +10638,8 @@ std::vector<int> DynamicPrintConfig::update_values_to_printer_extruders(DynamicP
         variant_count = 1;
     }
     else {
+        if (id_name == "print_extruder_id")
+            ensure_process_variant_columns(*this, printer_config);
         // Orca: emit the slots first, then size variant_count from what was actually
         // emitted. extruder_nozzle_volume_count only equals the emitted total when every
         // extruder carries per-type stats; an extruder with an empty stats entry combined

src/libslic3r/PrintConfig.hpp

@@ -214,6 +214,8 @@ enum class PrintOrder
 {
     Default,
     AsObjectList,
+    BestOfStrategies,    // run all custom strategies, pick the shortest total path
+    Snake,               // snake-like row traversal (back-and-forth) + 2-opt
     Count,
 };
 
@@ -1080,6 +1082,7 @@ PRINT_CONFIG_CLASS_DEFINE(
     ((ConfigOptionFloat,               brim_width))
     ((ConfigOptionFloat,               brim_ears_detection_length))
     ((ConfigOptionFloat,               brim_ears_max_angle))
+    ((ConfigOptionBool,                brim_ears_outer_only))
     ((ConfigOptionFloat,               skirt_start_angle))
     ((ConfigOptionBool,                bridge_no_support))
     ((ConfigOptionFloat,               elefant_foot_compensation))
@@ -1262,6 +1265,7 @@ PRINT_CONFIG_CLASS_DEFINE(
     ((ConfigOptionString,               sparse_infill_rotate_template))
     ((ConfigOptionPercent,              sparse_infill_density))
     ((ConfigOptionEnum<InfillPattern>,  sparse_infill_pattern))
+    ((ConfigOptionPercent,              sparse_infill_smooth_factor))
     ((ConfigOptionFloat,                lateral_lattice_angle_1))
     ((ConfigOptionFloat,                lateral_lattice_angle_2))
     ((ConfigOptionFloat,                infill_overhang_angle))
@@ -1543,7 +1547,7 @@ PRINT_CONFIG_CLASS_DEFINE(
     ((ConfigOptionBool,                gcode_add_line_number))
     ((ConfigOptionBool,                bbl_bed_temperature_gcode))
     ((ConfigOptionEnum<GCodeFlavor>,   gcode_flavor))
-
+    ((ConfigOptionBool,                gcode_skip_config_block))
     ((ConfigOptionFloat,               time_cost)) 
     ((ConfigOptionString,              layer_change_gcode))
     ((ConfigOptionString,              time_lapse_gcode))
@@ -1656,6 +1660,7 @@ PRINT_CONFIG_CLASS_DEFINE(
     ((ConfigOptionBool,                purge_in_prime_tower))
     ((ConfigOptionBool,                enable_filament_ramming))
     ((ConfigOptionBool,                tool_change_on_wipe_tower))
+    ((ConfigOptionBool,                wait_for_temp_on_wipe_tower))
     ((ConfigOptionBool,                support_multi_bed_types))
     ((ConfigOptionBool,                use_3mf))
 
@@ -1780,6 +1785,7 @@ PRINT_CONFIG_CLASS_DERIVED_DEFINE(
     ((ConfigOptionString,             filename_format))
     ((ConfigOptionStrings,            post_process))
     ((ConfigOptionStrings,            slicing_pipeline_plugin))
+    ((ConfigOptionString,             print_plugin_config_overrides))
     ((ConfigOptionString,             printer_model))
     ((ConfigOptionFloat,              resolution))
     ((ConfigOptionFloats,             retraction_minimum_travel))

src/libslic3r/PrintObject.cpp

@@ -1175,6 +1175,7 @@ bool PrintObject::invalidate_state_by_config_options(
             || opt_key == "brim_type"
             || opt_key == "brim_ears_max_angle"
             || opt_key == "brim_ears_detection_length"
+            || opt_key == "brim_ears_outer_only"
             // BBS: brim generation depends on printing speed
             || opt_key == "outer_wall_speed"
             || opt_key == "small_perimeter_speed"
@@ -1364,7 +1365,6 @@ bool PrintObject::invalidate_state_by_config_options(
             || opt_key == "infill_combination_max_layer_height"
             || opt_key == "bottom_shell_thickness"
             || opt_key == "top_shell_thickness"
-            || opt_key == "top_surface_expansion"
             || opt_key == "top_surface_expansion_margin"
             || opt_key == "top_surface_expansion_direction"
             || opt_key == "minimum_sparse_infill_area"
@@ -1400,7 +1400,6 @@ bool PrintObject::invalidate_state_by_config_options(
             || opt_key == "infill_anchor"
             || opt_key == "infill_anchor_max"
             || opt_key == "top_surface_line_width"
-            || opt_key == "top_surface_density"
             || opt_key == "bottom_surface_density"
             || opt_key == "center_of_surface_pattern"
             || opt_key == "separated_infills" 
@@ -1411,6 +1410,7 @@ bool PrintObject::invalidate_state_by_config_options(
             || opt_key == "infill_overhang_angle") {
             steps.emplace_back(posInfill);
         } else if (opt_key == "sparse_infill_pattern"
+                   || opt_key == "sparse_infill_smooth_factor"
                    || opt_key == "symmetric_infill_y_axis"
                    || opt_key == "infill_shift_step"
                    || opt_key == "sparse_infill_rotate_template"
@@ -1434,6 +1434,24 @@ bool PrintObject::invalidate_state_by_config_options(
                 is_approx(new_density->value, 0.) || is_approx(new_density->value, 100.))
                 steps.emplace_back(posPerimeters);
             steps.emplace_back(posPrepareInfill);
+        } else if (opt_key == "top_surface_density") {
+            // ORCA: 0% means no top solid fill, which switches off both the top surface expansion and the wall
+            // removal over top surfaces. Only crossing zero matters; posPerimeters cascades to posPrepareInfill.
+            const auto *old_density = old_config.option<ConfigOptionPercent>(opt_key);
+            const auto *new_density = new_config.option<ConfigOptionPercent>(opt_key);
+            assert(old_density && new_density);
+            if (is_approx(old_density->value, 0.) || is_approx(new_density->value, 0.))
+                steps.emplace_back(posPerimeters);
+            steps.emplace_back(posInfill);
+        } else if (opt_key == "top_surface_expansion") {
+            // ORCA: without the expansion the top fill never reaches the space freed by only_one_wall_top, so the
+            // walls over top surfaces are kept. Only crossing zero matters; posPerimeters cascades to posPrepareInfill.
+            const auto *old_expansion = old_config.option<ConfigOptionFloat>(opt_key);
+            const auto *new_expansion = new_config.option<ConfigOptionFloat>(opt_key);
+            assert(old_expansion && new_expansion);
+            if (old_expansion->value <= 0. || new_expansion->value <= 0.)
+                steps.emplace_back(posPerimeters);
+            steps.emplace_back(posPrepareInfill);
         } else if (opt_key == "internal_solid_infill_line_width") {
             // This value is used for calculating perimeter - infill overlap, thus perimeters need to be recalculated.
             steps.emplace_back(posPerimeters);
@@ -1760,51 +1778,50 @@ void PrintObject::detect_surfaces_type()
                         }
                     }
 
-                    // ORCA: Expand the top surfaces outward by top_surface_expansion in every direction. This
-                    // enlarges the top solid infill and, in particular, grows it over the covered material left
-                    // by features rising from the middle of a top surface (filling holes and joining tops so the
-                    // features rest on it). The expansion stays inside the section it belongs to: each connected
-                    // solid island has its own outer wall, so the top is grown within each island separately and
-                    // clipped to it - growing one island's top across the gap into another island (which may have
-                    // no top surface, leaving a partially filled layer) is never allowed. The top infill sits
-                    // inside the perimeters, so the margin is measured from the walls: the island is inset by the
-                    // band the walls consume (outer wall + inner walls) plus the configured margin, making that
-                    // value the real clearance between the expanded top and the walls (avoiding a hull line). The
-                    // original top is unioned back in, so where it already sits within that band it is kept as-is.
-                    // Never claims a bottom surface.
-                    const double top_expansion = layerm->region().config().top_surface_expansion.value;
-                    if (top_expansion > 0. && ! top.empty()) {
-                        const double     d        = scale_(top_expansion);
-                        const auto       jt       = Clipper2Lib::JoinType::Miter;
-                        const ExPolygons T        = union_ex(to_expolygons(top));
-                        const int    wall_loops = layerm->region().config().wall_loops.value;
+                    // ORCA: Grow the top surfaces by top_surface_expansion, so the top solid infill also covers the
+                    // material left by features rising from the middle of a top surface (filling the holes and
+                    // joining the tops, so the features rest on solid infill). Each connected island is grown and
+                    // clipped separately: growing one island's top across a gap into another - which may have no top
+                    // surface at all, leaving a partially filled layer - is never allowed. The original top is
+                    // unioned back in and bottom surfaces are never claimed, so this can only add area.
+                    const PrintRegionConfig &region_config  = layerm->region().config();
+                    const double             top_expansion  = region_config.top_surface_expansion.value;
+                    // Nothing to expand without a top fill: a 0% top surface density leaves the top layer with
+                    // walls only, and zero top shell layers retypes it as internal in prepare_fill_surfaces().
+                    if (top_expansion > 0. && region_config.top_shell_layers.value > 0 &&
+                        region_config.top_surface_density.value > 0. && ! top.empty()) {
+                        const double     d = scale_(top_expansion);
+                        const ExPolygons T = union_ex(to_expolygons(top));
+                        // Walls are laid out on spacing, not width; and only_one_wall_top leaves a single wall over
+                        // a top surface, which is exactly the situation handled here.
+                        const int    wall_loops = region_config.only_one_wall_top.value ? std::min(region_config.wall_loops.value, 1)
+                                                                                        : region_config.wall_loops.value;
                         const double wall_band  = wall_loops <= 0 ? 0. :
                             double(layerm->flow(frExternalPerimeter).scaled_width()) +
-                            double(layerm->flow(frPerimeter).scaled_width()) * double(wall_loops - 1);
-                        const double margin     = scale_(layerm->region().config().top_surface_expansion_margin.value);
+                            double(layerm->flow(frPerimeter).scaled_spacing()) * double(wall_loops - 1);
+                        const double margin     = scale_(region_config.top_surface_expansion_margin.value);
                         // minimum real top to act on: ignore anything thinner than ~2 top-infill lines
                         const float  min_top    = float(layerm->flow(frTopSolidInfill).scaled_width());
-                        const auto   direction  = layerm->region().config().top_surface_expansion_direction.value;
+                        const auto   direction  = region_config.top_surface_expansion_direction.value;
 
                         ExPolygons grown;
                         for (const ExPolygon &island : union_ex(layerm_slices_surfaces)) {
                             // The top infill only exists inside the perimeters, so seed and measure from the infill
-                            // region (the island minus the wall band), not the raw slice. A section whose only
-                            // exposed top lies in the wall band - i.e. a layer where the top is just the walls
-                            // themselves - has no infill here and is skipped, instead of being flooded inward by
-                            // the expansion. Thin slivers inside the infill region are dropped by the opening too.
+                            // region (the island minus the wall band), not the raw slice: a section whose exposed top
+                            // is just the walls themselves is then skipped instead of being flooded inward. Clip the
+                            // layer's tops to the island first, to keep the boolean ops proportional to the island.
                             const ExPolygons infill_region = wall_band > 0. ? offset_ex(island, -float(wall_band)) : ExPolygons{ island };
-                            const ExPolygons island_top    = intersection_ex(T, infill_region);
+                            const ExPolygons island_top    = intersection_ex(
+                                ClipperUtils::clip_clipper_polygons_with_subject_bbox(T, get_extents(island).inflated(SCALED_EPSILON)),
+                                infill_region);
                             if (opening_ex(island_top, min_top).empty())
                                 continue; // no real top infill in this section - never expand into it
 
-                            // grow by d, then keep only the part allowed by the configured direction: inward fills
-                            // the holes/gaps left by features (clip the growth back to the top's own filled outline,
-                            // which leaves the outer edge fixed), outward grows the outer edge toward the walls (drop
-                            // the growth that fell into the original holes), and inward+outward keeps both.
-                            ExPolygons expanded = offset_ex_2(island_top, d, jt);
+                            // Grow, then keep only what the configured direction allows, using the top's own filled
+                            // outline (same outer edge, holes closed) to tell the two apart.
+                            ExPolygons expanded = offset_ex_2(island_top, d, Clipper2Lib::JoinType::Miter);
                             if (direction != TopSurfaceExpansionDirection::InwardAndOutward) {
-                                ExPolygons outline; // the top with its holes filled (same outer edge)
+                                ExPolygons outline;
                                 outline.reserve(island_top.size());
                                 for (const ExPolygon &ex : island_top)
                                     outline.emplace_back(ex.contour);

src/libslic3r/SLA/IndexedMesh.cpp

@@ -56,12 +56,12 @@ public:
                             int &                        i,
                             Eigen::Matrix<double, 1, 3> &closest)
     {
-        size_t idx_unsigned = 0;
-        Vec3d  closest_vec3d(closest);
-        double dist =
+        size_t idx_unsigned { 0 };
+        Vec3d  closest_vec3d { Vec3d::Zero() };
+        const double dist {
             AABBTreeIndirect::squared_distance_to_indexed_triangle_set(
                 its.vertices, its.indices, m_tree, point, idx_unsigned,
-                closest_vec3d);
+                closest_vec3d) };
         i       = int(idx_unsigned);
         closest = closest_vec3d;
         return dist;

src/libslic3r/ShortestPath.cpp

@@ -10,6 +10,7 @@
 #include "KDTreeIndirect.hpp"
 #include "MutablePriorityQueue.hpp"
 #include "Print.hpp"
+#include "GCode/OrderingStrategies.hpp"
 
 #include <cmath>
 #include <cassert>
@@ -1103,7 +1104,7 @@ std::vector<size_t> chain_expolygons(const ExPolygons &input_exploy) {
 	return chain_points(points);
 }
 
-std::vector<size_t> chain_points(const Points &points, Point *start_near)
+std::vector<size_t> chain_points(const Points &points, const Point *start_near)
 {
 	auto segment_end_point = [&points](size_t idx, bool /* first_point */) -> const Point& { return points[idx]; };
 	std::vector<std::pair<size_t, bool>> ordered = chain_segments_greedy<Point, decltype(segment_end_point)>(segment_end_point, points.size(), start_near);
@@ -1111,9 +1112,26 @@ std::vector<size_t> chain_points(const Points &points, Point *start_near)
 	out.reserve(ordered.size());
 	for (auto &segment_and_reversal : ordered)
 		out.emplace_back(segment_and_reversal.first);
+
 	return out;
 }
 
+std::vector<size_t> chain_points_with_postprocessing(const Points &points, const Point *start_near)
+{
+	std::vector<size_t> path = chain_points(points, start_near);
+	// Alternate 2-opt and crossing removal until convergence.
+	// 2-opt can create new crossings, and crossing removal can create new
+	// opportunities for 2-opt improvement. Break early if neither improves.
+	for (int iter = 0; iter < 3; ++iter) {
+		bool improved = tsp_2opt_improve(path, points);
+		improved |= tsp_remove_crossings(path, points);
+		if (!improved) break;
+	}
+    if (start_near == nullptr)
+        tsp_rotate_minimize_closing(path, points);
+	return path;
+}
+
 #ifndef NDEBUG
 	// #define DEBUG_SVG_OUTPUT
 #endif /* NDEBUG */
@@ -2025,12 +2043,13 @@ std::vector<const PrintInstance*> chain_print_object_instances(const std::vector
 			instances.emplace_back(i, j);
 		}
 	}
-	auto segment_end_point = [&object_reference_points](size_t idx, bool /* first_point */) -> const Point& { return object_reference_points[idx]; };
-	std::vector<std::pair<size_t, bool>> ordered = chain_segments_greedy<Point, decltype(segment_end_point)>(segment_end_point, instances.size(), start_near);
+	// Order objects using nearest neighbor + post-processing (crossing removal + 2-opt).
+	std::vector<size_t> path = chain_points_with_postprocessing(object_reference_points, start_near);
+
 	std::vector<const PrintInstance*> out;
-	out.reserve(instances.size());
-	for (auto& segment_and_reversal : ordered) {
-		const std::pair<size_t, size_t>& inst = instances[segment_and_reversal.first];
+	out.reserve(path.size());
+	for (size_t idx : path) {
+		const std::pair<size_t, size_t>& inst = instances[idx];
 		out.emplace_back(&print_objects[inst.first]->instances()[inst.second]);
 	}
 	return out;

src/libslic3r/ShortestPath.hpp

@@ -15,7 +15,9 @@ namespace Slic3r {
 		using PolyNodes = std::vector<PolyNode*, PointsAllocator<PolyNode*>>;
 	}
 
-std::vector<size_t> 				 chain_points(const Points &points, Point *start_near = nullptr);
+std::vector<size_t> 				 chain_points(const Points &points, const Point *start_near = nullptr);
+// Variant with post-processing (crossing removal + 2-opt) for object ordering.
+std::vector<size_t> 				 chain_points_with_postprocessing(const Points &points, const Point *start_near = nullptr);
 std::vector<size_t> 				 chain_expolygons(const ExPolygons &input_exploy);
 
 std::vector<std::pair<size_t, bool>> chain_extrusion_entities(std::vector<ExtrusionEntity*> &entities, const Point *start_near = nullptr);

src/libslic3r/Support/SupportCommon.cpp

@@ -65,6 +65,15 @@ std::pair<SupportGeneratorLayersPtr, SupportGeneratorLayersPtr> generate_interfa
         const bool                 smooth_supports        = support_params.support_style != smsGrid;
         SupportGeneratorLayersPtr &interface_layers       = base_and_interface_layers.first;
         SupportGeneratorLayersPtr &base_interface_layers  = base_and_interface_layers.second;
+        // The user-facing interface layer counts include the contact layer. Internally,
+        // contact layers are generated separately, so only the remaining layers are
+        // projected into intermediate interface/base-interface layers here.
+        const size_t num_top_interface_layers    = support_params.has_top_contacts    ? support_params.num_top_interface_layers    - 1 : 0;
+        const size_t num_bottom_interface_layers = support_params.has_bottom_contacts ? support_params.num_bottom_interface_layers - 1 : 0;
+        const size_t num_top_base_interface_layers    = std::min(support_params.num_top_base_interface_layers,    num_top_interface_layers);
+        const size_t num_bottom_base_interface_layers = std::min(support_params.num_bottom_base_interface_layers, num_bottom_interface_layers);
+        const size_t num_top_interface_layers_only    = num_top_interface_layers    - num_top_base_interface_layers;
+        const size_t num_bottom_interface_layers_only = num_bottom_interface_layers - num_bottom_base_interface_layers;
 
         interface_layers.assign(intermediate_layers.size(), nullptr);
         if (support_params.has_base_interfaces())
@@ -124,6 +133,8 @@ std::pair<SupportGeneratorLayersPtr, SupportGeneratorLayersPtr> generate_interfa
         };
         tbb::parallel_for(tbb::blocked_range<int>(0, int(intermediate_layers.size())),
             [&bottom_contacts, &top_contacts, &top_interface_layers, &top_base_interface_layers, &intermediate_layers, &insert_layer, &support_params,
+             num_top_interface_layers, num_bottom_interface_layers, num_top_base_interface_layers, num_bottom_base_interface_layers,
+             num_top_interface_layers_only, num_bottom_interface_layers_only,
              snug_supports, &interface_layers, &base_interface_layers](const tbb::blocked_range<int>& range) {
                 // Gather the top / bottom contact layers intersecting with num_interface_layers resp. num_interface_layers_only intermediate layers above / below
                 // this intermediate layer.
@@ -142,16 +153,16 @@ std::pair<SupportGeneratorLayersPtr, SupportGeneratorLayersPtr> generate_interfa
                     Polygons polygons_top_contact_projected_base;
                     Polygons polygons_bottom_contact_projected_interface;
                     Polygons polygons_bottom_contact_projected_base;
-                    if (support_params.num_top_interface_layers > 0) {
+                    if (num_top_interface_layers > 0) {
                         // Top Z coordinate of a slab, over which we are collecting the top / bottom contact surfaces
-                        coordf_t top_z              = intermediate_layers[std::min(num_intermediate - 1, idx_intermediate_layer + int(support_params.num_top_interface_layers) - 1)]->print_z;
-                        coordf_t top_inteface_z     = std::numeric_limits<coordf_t>::max();
-                        if (support_params.num_top_base_interface_layers > 0)
+                        coordf_t top_z              = intermediate_layers[std::min(num_intermediate - 1, idx_intermediate_layer + int(num_top_interface_layers) - 1)]->print_z;
+                        coordf_t top_interface_z     = std::numeric_limits<coordf_t>::max();
+                        if (num_top_base_interface_layers > 0)
                             // Some top base interface layers will be generated.
-                            top_inteface_z = support_params.num_top_interface_layers_only() == 0 ?
+                            top_interface_z = num_top_interface_layers_only == 0 ?
                                 // Only base interface layers to generate.
                                 - std::numeric_limits<coordf_t>::max() :
-                                intermediate_layers[std::min(num_intermediate - 1, idx_intermediate_layer + int(support_params.num_top_interface_layers_only()) - 1)]->print_z;
+                                intermediate_layers[std::min(num_intermediate - 1, idx_intermediate_layer + int(num_top_interface_layers_only) - 1)]->print_z;
                         // Move idx_top_contact_first up until above the current print_z.
                         idx_top_contact_first = idx_higher_or_equal(top_contacts, idx_top_contact_first, [&intermediate_layer](const SupportGeneratorLayer *layer){ return layer->print_z >= intermediate_layer.print_z; }); //  - EPSILON
                         // Collect the top contact areas above this intermediate layer, below top_z.
@@ -160,22 +171,22 @@ std::pair<SupportGeneratorLayersPtr, SupportGeneratorLayersPtr> generate_interfa
                             //FIXME maybe this adds one interface layer in excess?
                             if (top_contact_layer.bottom_z - EPSILON > top_z)
                                 break;
-                            polygons_append(top_contact_layer.bottom_z - EPSILON > top_inteface_z ? polygons_top_contact_projected_base : polygons_top_contact_projected_interface,
+                            polygons_append(top_contact_layer.bottom_z - EPSILON > top_interface_z ? polygons_top_contact_projected_base : polygons_top_contact_projected_interface,
                                 // For snug supports, project the overhang polygons covering the whole overhang, so that they will merge without a gap with support polygons of the other layers.
                                 // For grid supports, merging of support regions will be performed by the projection into grid.
                                 snug_supports ? *top_contact_layer.overhang_polygons : top_contact_layer.polygons);
                         }
                     }
-                    if (support_params.num_bottom_interface_layers > 0) {
+                    if (num_bottom_interface_layers > 0) {
                         // Bottom Z coordinate of a slab, over which we are collecting the top / bottom contact surfaces
-                        coordf_t bottom_z           = intermediate_layers[std::max(0, idx_intermediate_layer - int(support_params.num_bottom_interface_layers) + 1)]->bottom_z;
+                        coordf_t bottom_z           = intermediate_layers[std::max(0, idx_intermediate_layer - int(num_bottom_interface_layers) + 1)]->bottom_z;
                         coordf_t bottom_interface_z = - std::numeric_limits<coordf_t>::max();
-                        if (support_params.num_bottom_base_interface_layers > 0)
+                        if (num_bottom_base_interface_layers > 0)
                             // Some bottom base interface layers will be generated.
-                            bottom_interface_z = support_params.num_bottom_interface_layers_only() == 0 ?
+                            bottom_interface_z = num_bottom_interface_layers_only == 0 ?
                                 // Only base interface layers to generate.
                                 std::numeric_limits<coordf_t>::max() :
-                                intermediate_layers[std::max(0, idx_intermediate_layer - int(support_params.num_bottom_interface_layers_only()))]->bottom_z;
+                                intermediate_layers[std::max(0, idx_intermediate_layer - int(num_bottom_interface_layers_only))]->bottom_z;
                         // Move idx_bottom_contact_first up until touching bottom_z.
                         idx_bottom_contact_first = idx_higher_or_equal(bottom_contacts, idx_bottom_contact_first, [bottom_z](const SupportGeneratorLayer *layer){ return layer->print_z >= bottom_z - EPSILON; });
                         // Collect the top contact areas above this intermediate layer, below top_z.
@@ -1563,13 +1574,17 @@ void generate_support_toolpaths(
         // Pointer to the 1st layer interface filler.
         auto filler_first_layer     = filler_first_layer_ptr ? filler_first_layer_ptr.get() : filler_interface.get();
         // Filler for the 1st layer interface, if different from filler_interface.
-        auto filler_raft_contact_ptr = std::unique_ptr<Fill>(range.begin() == n_raft_layers && config.support_interface_top_layers.value == 0 ?
+        const bool top_interfaces_enabled    = support_params.num_top_interface_layers > 0;
+        const bool bottom_interfaces_enabled = support_params.num_bottom_interface_layers > 0;
+        const coordf_t base_interface_density = top_interfaces_enabled || !bottom_interfaces_enabled ?
+            support_params.top_interface_density : support_params.bottom_interface_density;
+        auto filler_raft_contact_ptr = std::unique_ptr<Fill>(range.begin() == n_raft_layers && !top_interfaces_enabled ?
             Fill::new_from_type(support_params.raft_interface_fill_pattern) : nullptr);
         // Pointer to the 1st layer interface filler.
         auto filler_raft_contact     = filler_raft_contact_ptr ? filler_raft_contact_ptr.get() : filler_interface.get();
         // Filler for the base interface (to be used for soluble interface / non soluble base, to produce non soluble interface layer below soluble interface layer).
         auto filler_base_interface  = std::unique_ptr<Fill>(base_interface_layers.empty() ? nullptr :
-            Fill::new_from_type(support_params.top_interface_density > 0.95 || support_params.with_sheath ? ipRectilinear : ipSupportBase));
+            Fill::new_from_type(base_interface_density > 0.95 || support_params.with_sheath ? ipRectilinear : ipSupportBase));
         auto filler_support         = std::unique_ptr<Fill>(Fill::new_from_type(support_params.base_fill_pattern));
         filler_interface->set_bounding_box(bbox_object);
         if (filler_first_layer_ptr)
@@ -1583,10 +1598,7 @@ void generate_support_toolpaths(
         {
             SupportLayer &support_layer = *support_layers[support_layer_id];
             LayerCache   &layer_cache   = layer_caches[support_layer_id];
-            const float   support_interface_angle = (config.support_interface_pattern == smipRectilinearInterlaced) ?
-                support_params.raft_interface_angle(support_layer.interface_id()) :
-                ((support_params.support_style == smsGrid || config.support_interface_pattern == smipRectilinear) ?
-                support_params.interface_angle : support_params.raft_interface_angle(support_layer.interface_id()));
+            const float   support_interface_angle = support_params.support_interface_angle(support_layer.interface_id());
 
             // Find polygons with the same print_z.
             SupportGeneratorLayerExtruded &bottom_contact_layer = layer_cache.bottom_contact_layer;
@@ -1619,7 +1631,9 @@ void generate_support_toolpaths(
             bool raft_layer = slicing_params.interface_raft_layers && top_contact_layer.layer && is_approx(top_contact_layer.layer->print_z, slicing_params.raft_contact_top_z);
             // ORCA: Organic tree uses projected contacts to build the interface stack; avoid extra bottom-contact extrusion.
             const bool organic_tree = support_params.support_style == SupportMaterialStyle::smsTreeOrganic;
-            if (config.support_interface_top_layers == 0) {
+            const bool top_interfaces = support_params.num_top_interface_layers > 0;
+            const bool bottom_interfaces = support_params.num_bottom_interface_layers > 0;
+            if (!top_interfaces) {
                 // If no top interface layers were requested, we treat the contact layer exactly as a generic base layer.
                 // Don't merge the raft contact layer though.
                 if (support_params.can_merge_support_regions && ! raft_layer) {
@@ -1642,15 +1656,29 @@ void generate_support_toolpaths(
                 if (top_contact_layer.could_merge(interface_layer) && ! raft_layer)
                     top_contact_layer.merge(std::move(interface_layer));
             }
-            if ((config.support_interface_top_layers == 0 || config.support_interface_bottom_layers == 0) && support_params.can_merge_support_regions) {
+            if (!bottom_interfaces && support_params.can_merge_support_regions) {
                 if (base_layer.could_merge(bottom_contact_layer))
                     base_layer.merge(std::move(bottom_contact_layer));
                 else if (base_layer.empty() && ! bottom_contact_layer.empty() && ! bottom_contact_layer.layer->bridging)
                     base_layer = std::move(bottom_contact_layer);
             } else if (bottom_contact_layer.could_merge(top_contact_layer) && ! raft_layer) {
-                top_contact_layer.merge(std::move(bottom_contact_layer));
+                if (top_interfaces && bottom_interfaces) {
+                    top_contact_layer.merge(std::move(bottom_contact_layer));
+                } else if (bottom_interfaces) {
+                    top_contact_layer.set_polygons_to_extrude(
+                        diff(top_contact_layer.polygons_to_extrude(), bottom_contact_layer.polygons_to_extrude()));
+                } else {
+                    bottom_contact_layer.set_polygons_to_extrude(
+                        diff(bottom_contact_layer.polygons_to_extrude(), top_contact_layer.polygons_to_extrude()));
+                }
             } else if (bottom_contact_layer.could_merge(interface_layer) && ! organic_tree) {
-                bottom_contact_layer.merge(std::move(interface_layer));
+                const bool interface_layer_is_bottom = interface_layer.layer->layer_type == SupporLayerType::BottomInterface;
+                if (bottom_interfaces && interface_layer_is_bottom) {
+                    bottom_contact_layer.merge(std::move(interface_layer));
+                } else {
+                    bottom_contact_layer.set_polygons_to_extrude(
+                        diff(bottom_contact_layer.polygons_to_extrude(), interface_layer.polygons_to_extrude()));
+                }
             }
 
             // Orca: For organic trees the support-material regions are generated from
@@ -1730,12 +1758,12 @@ void generate_support_toolpaths(
                         interface_as_base ? ExtrusionRole::erSupportMaterial : ExtrusionRole::erSupportMaterialInterface, interface_flow);
                 }
             };
-            const bool top_interfaces = support_params.num_top_interface_layers > 0;
-            const bool bottom_interfaces = top_interfaces && support_params.num_bottom_interface_layers > 0;
             extrude_interface(top_contact_layer,    raft_layer ? InterfaceLayerType::RaftContact : top_interfaces ? InterfaceLayerType::TopContact : InterfaceLayerType::InterfaceAsBase);
             if (!organic_tree)
                 extrude_interface(bottom_contact_layer, bottom_interfaces ? InterfaceLayerType::BottomContact : InterfaceLayerType::InterfaceAsBase);
-            extrude_interface(interface_layer,      top_interfaces ? InterfaceLayerType::Interface : InterfaceLayerType::InterfaceAsBase);
+            const bool interface_layer_enabled = !interface_layer.empty() &&
+                (interface_layer.layer->layer_type == SupporLayerType::BottomInterface ? bottom_interfaces : top_interfaces);
+            extrude_interface(interface_layer,      interface_layer_enabled ? InterfaceLayerType::Interface : InterfaceLayerType::InterfaceAsBase);
             // Base interface layers under soluble interfaces
             if ( ! base_interface_layer.empty() && ! base_interface_layer.polygons_to_extrude().empty()) {
                 Fill *filler = filler_base_interface.get();
@@ -1745,7 +1773,7 @@ void generate_support_toolpaths(
                 Flow interface_flow = support_params.support_material_flow.with_height(float(base_interface_layer.layer->height));
                 filler->angle   = support_interface_angle;
                 filler->spacing = support_params.support_material_interface_flow.spacing();
-                    filler->link_max_length = coord_t(scale_(filler->spacing * link_max_length_factor / support_params.top_interface_density));
+                filler->link_max_length = coord_t(scale_(filler->spacing * link_max_length_factor / base_interface_density));
                 fill_expolygons_generate_paths(
                     // Destination
                     base_interface_layer.extrusions,
@@ -1753,7 +1781,7 @@ void generate_support_toolpaths(
                     // Regions to fill
                     union_safety_offset_ex(base_interface_layer.polygons_to_extrude()),
                     // Filler and its parameters
-                    filler, float(support_params.top_interface_density),
+                    filler, float(base_interface_density),
                     // Extrusion parameters
                     ExtrusionRole::erSupportMaterial, interface_flow);
             }

src/libslic3r/Support/SupportParameters.hpp

@@ -34,7 +34,7 @@ struct SupportParameters {
 
 	    {
 	        this->num_top_interface_layers    = std::max(0, object_config.support_interface_top_layers.value);
-	        this->num_bottom_interface_layers = number_of_support_interface_bottom_layers(object_config);
+	        this->num_bottom_interface_layers = std::max(0, number_of_support_interface_bottom_layers(object_config));
 	        this->has_top_contacts              = num_top_interface_layers    > 0;
 	        this->has_bottom_contacts           = num_bottom_interface_layers > 0;
             // BBS: if support interface and support base do not use the same filament, add a base layer to improve their adhesion
@@ -46,15 +46,15 @@ struct SupportParameters {
             if (non_soluble_base_top) { // ORCA: Try to support soluble dense interfaces with non-soluble dense interfaces.
                 this->num_top_base_interface_layers = size_t(std::min(int(num_top_interface_layers) / 2, 2));
             } else {
-                this->num_top_base_interface_layers =
-                    (different_support_interface_filament && this->zero_gap_interface_top) ? 1 : 0;
+                // Keep at least one configured layer on the interface filament.
+                this->num_top_base_interface_layers = different_support_interface_filament && num_top_interface_layers > 1 ? 1 : 0;
             }
 
             if (non_soluble_base_bottom) { // ORCA: Try to support soluble dense interfaces with non-soluble dense interfaces.
                 this->num_bottom_base_interface_layers = size_t(std::min(int(num_bottom_interface_layers) / 2, 2));
             } else {
-                this->num_bottom_base_interface_layers =
-                    (different_support_interface_filament && this->zero_gap_interface_bottom) ? 1 : 0;
+                // Keep at least one configured layer on the interface filament.
+                this->num_bottom_base_interface_layers = different_support_interface_filament && num_bottom_interface_layers > 1 ? 1 : 0;
             }
 	    }
         this->first_layer_flow = Slic3r::support_material_1st_layer_flow(&object, float(slicing_params.first_print_layer_height));
@@ -74,7 +74,7 @@ struct SupportParameters {
         for (auto layer : object.layers())
             this->support_layer_height_min = std::min(this->support_layer_height_min, std::max(0.01, layer->height));
         
-        if (object_config.support_interface_top_layers.value == 0) {
+        if (this->num_top_interface_layers == 0 && this->num_bottom_interface_layers == 0) {
             // No interface layers allowed, print everything with the base support pattern.
             this->support_material_interface_flow = this->support_material_flow;
         }
@@ -120,8 +120,8 @@ struct SupportParameters {
         this->raft_interface_density = std::min(1., this->raft_interface_flow.spacing() / raft_interface_spacing);
         this->support_spacing = object_config.support_base_pattern_spacing.value + this->support_material_flow.spacing();
         this->support_density = std::min(1., this->support_material_flow.spacing() / this->support_spacing);
-        if (object_config.support_interface_top_layers.value == 0) {
-            // No interface layers allowed, print everything with the base support pattern.
+        if (this->num_top_interface_layers == 0) {
+            // No top interface layers allowed; keep unused top interface parameters aligned with base support.
             this->top_interface_spacing = this->support_spacing;
             this->top_interface_density = this->support_density;
         }
@@ -133,16 +133,20 @@ struct SupportParameters {
             this->support_density > 0.95 || this->with_sheath ? ipRectilinear : ipSupportBase;
         this->interface_fill_pattern = (this->top_interface_density > 0.95 ? ipRectilinear : ipSupportBase);
         this->raft_interface_fill_pattern = this->raft_interface_density > 0.95 ? ipRectilinear : ipSupportBase;
+        const coordf_t contact_interface_density = this->num_top_interface_layers > 0 ?
+            this->top_interface_density : this->bottom_interface_density;
+        const bool zero_gap_contact_interface = this->num_top_interface_layers > 0 ?
+            this->zero_gap_interface_top : this->zero_gap_interface_bottom;
         if (object_config.support_interface_pattern == smipGrid)
             this->contact_fill_pattern = ipGrid;
         else if (object_config.support_interface_pattern == smipRectilinearInterlaced)
             this->contact_fill_pattern = ipRectilinear;
         else
             this->contact_fill_pattern =
-            (object_config.support_interface_pattern == smipAuto && this->zero_gap_interface_top) ||
+            (object_config.support_interface_pattern == smipAuto && zero_gap_contact_interface) ||
             object_config.support_interface_pattern == smipConcentric ?
             ipConcentric :
-            (this->top_interface_density > 0.95 ? ipRectilinear : ipSupportBase);
+            (contact_interface_density > 0.95 ? ipRectilinear : ipSupportBase);
 
         this->raft_angle_1st_layer  = 0.f;
         this->raft_angle_base       = 0.f;
@@ -188,6 +192,7 @@ struct SupportParameters {
                                                                                                           std::numeric_limits<double>::max();
 
         support_style = object_config.support_style;
+        support_interface_pattern = object_config.support_interface_pattern;
         if (support_style != smsDefault) {
             if ((support_style == smsSnug || support_style == smsGrid) && is_tree(object_config.support_type)) support_style = smsDefault;
             if ((support_style == smsTreeSlim || support_style == smsTreeStrong || support_style == smsTreeHybrid || support_style == smsTreeOrganic) &&
@@ -211,9 +216,9 @@ struct SupportParameters {
     bool                    has_top_contacts;
     // Is there at least a bottom contact layer extruded below support base?
     bool                    has_bottom_contacts;
-    // Number of top interface layers without counting the contact layer.
+    // User-configured number of top interface layers, including the contact layer.
     size_t                  num_top_interface_layers;
-    // Number of bottom interface layers without counting the contact layer.
+    // User-configured number of bottom interface layers, including the contact layer.
     size_t                  num_bottom_interface_layers;
     // Number of top base interface layers.
     size_t                  num_top_base_interface_layers;
@@ -235,7 +240,7 @@ struct SupportParameters {
 	Flow 					support_material_interface_flow;
 	// Flow at the bottom interfaces and contacts.
 	Flow 					support_material_bottom_interface_flow;
-	// Flow at raft inteface & contact layers.
+	// Flow at raft interface & contact layers.
 	Flow    				raft_interface_flow;
     coordf_t support_extrusion_width;
 	// Is merging of regions allowed? Could the interface & base support regions be printed with the same extruder?
@@ -262,6 +267,7 @@ struct SupportParameters {
     // Density of the base support layers.
     coordf_t 				support_density;
     SupportMaterialStyle    support_style = smsDefault;
+    SupportMaterialInterfacePattern support_interface_pattern = smipAuto;
 
     // Pattern of the sparse infill including sparse raft layers.
     InfillPattern           base_fill_pattern;
@@ -280,9 +286,33 @@ struct SupportParameters {
     float 					raft_angle_base;
     float 					raft_angle_interface;
 
-    // Produce a raft interface angle for a given SupportLayer::interface_id()
+    // Produce a +/-45deg alternating raft interface angle for a given SupportLayer::interface_id().
     float 					raft_interface_angle(size_t interface_id) const 
-    	{ return this->raft_angle_interface + ((interface_id & 1) ? float(- M_PI / 4.) : float(+ M_PI / 4.)); }
+    	{ return this->raft_angle_interface + ((interface_id & 1) ? float(- M_PI_4) : float(+ M_PI_4)); }
+
+    // Produce support interface angle for a given SupportLayer::interface_id().
+    // Angle will be shifted/rotated based on interface pattern.
+    float 					support_interface_angle(size_t interface_id) const 
+    	{ 
+            float angle;
+            
+            switch (this->support_interface_pattern) {
+                case SupportMaterialInterfacePattern::smipRectilinear:
+                    angle = support_style == SupportMaterialStyle::smsSnug ? this->interface_angle - float(M_PI_4) : this->interface_angle;
+                    break;
+                case SupportMaterialInterfacePattern::smipRectilinearInterlaced:
+                    angle = this->interface_angle + ((interface_id & 1) ? float(M_PI_4) : float(-M_PI_4));
+                    break;
+                case SupportMaterialInterfacePattern::smipGrid:
+                    angle = this->base_angle;
+                    break;
+                default:
+                    angle = this->interface_angle;
+                    break;
+            }
+
+            return angle;
+        }
 		
     bool independent_layer_height = false;
     const double thresh_big_overhang = Slic3r::sqr(scale_(10));

src/libslic3r/Support/TreeModelVolumes.cpp

@@ -469,7 +469,7 @@ void TreeModelVolumes::calculateCollision(const coord_t radius, const LayerIndex
             });
 
             // 2) Sum over top / bottom ranges.
-            const bool processing_last_mesh = outline_idx == layer_outline_indices.size();
+            const bool processing_last_mesh = outline_idx == layer_outline_indices.back();
             tbb::parallel_for(tbb::blocked_range<LayerIndex>(data.begin(), data.end()),
                 [&collision_areas_offsetted, &outlines, &machine_border = m_machine_border, &anti_overhang = m_anti_overhang, radius, 
                     xy_distance, z_distance_bottom_layers, z_distance_top_layers, min_resolution = m_min_resolution, &data, processing_last_mesh, &throw_on_cancel]

src/libslic3r/Support/TreeSupport.cpp

@@ -1511,7 +1511,9 @@ void TreeSupport::generate_toolpaths()
                     // ORCA: reset interface Fill state per area group to keep angles deterministic.
                     filler_interface->fixed_angle = false;
                     filler_interface->layer_id = size_t(-1);
-                    filler_interface->angle = base_support_angle + M_PI_2; // default interface angle is perpendicular to support angle
+                    filler_Roof1stLayer->fixed_angle = false;
+                    filler_Roof1stLayer->layer_id = size_t(-1);
+                    filler_interface->angle = m_support_params.support_interface_angle(area_group.interface_id);
                     if (area_group.type != SupportLayer::BaseType) {
                         // interface
                         if (layer_id == 0) {
@@ -1537,8 +1539,10 @@ void TreeSupport::generate_toolpaths()
                         fill_params.density = interface_density;
                         // Note: spacing means the separation between two lines as if they are tightly extruded
                         filler_Roof1stLayer->spacing = interface_flow.spacing();
-                        filler_Roof1stLayer->angle = base_support_angle;
+                        filler_Roof1stLayer->angle = m_support_params.support_interface_angle(area_group.interface_id);
                         fill_params.dont_sort = true;
+                        filler_Roof1stLayer->fixed_angle = (m_object_config->support_interface_pattern == smipRectilinearInterlaced ||
+                                                            m_object_config->support_interface_pattern == smipRectilinear);
                         Flow interface_base_flow = interface_as_base ? support_flow : interface_flow;
                         ExtrusionRole interface_role = interface_as_base ? erSupportMaterial : erSupportMaterialInterface;
                         // generate a perimeter first to support interface better
@@ -1556,18 +1560,11 @@ void TreeSupport::generate_toolpaths()
                         fill_params.density = bottom_interface_density;
                         filler_interface->spacing = interface_flow.spacing();
 
-                        if (m_object_config->support_interface_pattern == smipGrid) {
-                            filler_interface->angle = base_support_angle;
-                            fill_params.dont_sort = true;
-                        }
-
-                        if (m_object_config->support_interface_pattern == smipRectilinearInterlaced) {
-                            // ORCA: explicit 0/90 alternation for rectilinear interlaced interfaces.
-                            filler_interface->fixed_angle = true;
-                            filler_interface->angle = base_support_angle + ((area_group.interface_id & 1) * M_PI_2);
-                            fill_params.dont_sort = true;
-                        }
+                        fill_params.dont_sort = (m_object_config->support_interface_pattern == smipGrid ||
+                                                m_object_config->support_interface_pattern == smipRectilinearInterlaced);   
 
+                        filler_interface->fixed_angle = (m_object_config->support_interface_pattern == smipRectilinearInterlaced ||
+                                                        m_object_config->support_interface_pattern == smipRectilinear);
 
                         Flow interface_base_flow = interface_as_base ? support_flow : interface_flow;
                         ExtrusionRole interface_role = interface_as_base ? erSupportMaterial : erSupportMaterialInterface;
@@ -1579,17 +1576,11 @@ void TreeSupport::generate_toolpaths()
                         fill_params.density       = interface_density;
                         filler_interface->spacing = interface_flow.spacing();
 
-                        if (m_object_config->support_interface_pattern == smipGrid) {
-                            filler_interface->angle = base_support_angle;
-                            fill_params.dont_sort = true;
-                        }
+                        fill_params.dont_sort = (m_object_config->support_interface_pattern == smipGrid ||
+                                                m_object_config->support_interface_pattern == smipRectilinearInterlaced);   
 
-                        if (m_object_config->support_interface_pattern == smipRectilinearInterlaced) {
-                            // ORCA: explicit 0/90 alternation for rectilinear interlaced interfaces.
-                            filler_interface->fixed_angle = true;
-                            filler_interface->angle = base_support_angle + ((area_group.interface_id & 1) * M_PI_2);
-                            fill_params.dont_sort = true;
-                        }
+                        filler_interface->fixed_angle = (m_object_config->support_interface_pattern == smipRectilinearInterlaced ||
+                                                        m_object_config->support_interface_pattern == smipRectilinear);
 
                         Flow interface_base_flow = interface_as_base ? support_flow : interface_flow;
                         ExtrusionRole interface_role = interface_as_base ? erSupportMaterial : erSupportMaterialInterface;
@@ -2014,6 +2005,9 @@ void TreeSupport::draw_circles()
     // generate areas
     const coordf_t layer_height = config.layer_height.value;
     const size_t top_interface_layers = m_support_params.num_top_interface_layers;
+    const int top_base_interface_layers = std::min<int>(
+        int(m_support_params.num_top_base_interface_layers),
+        top_interface_layers > 0 ? int(top_interface_layers) - 1 : 0);
     const size_t bottom_interface_layers = number_of_support_interface_bottom_layers(config);
     const double nozzle_diameter = m_object->print()->config().nozzle_diameter.get_at(0);
     const coordf_t line_width = config.get_abs_value("support_line_width", nozzle_diameter);
@@ -2054,12 +2048,14 @@ void TreeSupport::draw_circles()
 
                 ExPolygons& base_areas = ts_layer->base_areas;
                 ExPolygons& roof_areas = ts_layer->roof_areas;
+                ExPolygons roof_base_areas;
                 ExPolygons& roof_1st_layer = ts_layer->roof_1st_layer;
                 ExPolygons& floor_areas = ts_layer->floor_areas;
                 ExPolygons& roof_gap_areas = ts_layer->roof_gap_areas;
                 coordf_t         max_layers_above_base = 0;
                 coordf_t         max_layers_above_roof = 0;
                 coordf_t         max_layers_above_roof1 = 0;
+                size_t           first_base_roof_area = 0;
                 bool             floor_interface_as_base = false;
                 bool has_circle_node = false;
                 bool need_extra_wall = false;
@@ -2094,8 +2090,6 @@ void TreeSupport::draw_circles()
                         break;
 
                     const SupportNode& node = *p_node;
-                    // ORCA: Cap top interface height in mm based on per-node support layer height.
-                    const coordf_t top_interface_height = coordf_t(top_interface_layers) * node.height;
                     ExPolygons area;
                     // Generate directly from overhang polygon if one of the following is true:
                     // 1) node is a normal part of hybrid support
@@ -2159,18 +2153,16 @@ void TreeSupport::draw_circles()
 
                     if (obj_layer_nr>0 && node.distance_to_top < 0)
                         append(roof_gap_areas, area);
-                    // ORCA: Roof1stLayer must also fit inside the mm cap.
                     else if (obj_layer_nr > 0 && node.support_roof_layers_below == 1 &&
-                             (node.dist_mm_to_top - this->top_z_distance) < top_interface_height + EPSILON && node.is_sharp_tail==false)
+                             node.is_sharp_tail == false)
                     {
                         append(roof_1st_layer, area);
                         max_layers_above_roof1 = std::max(max_layers_above_roof1, node.dist_mm_to_top);
                     }
-                    // ORCA: Roof layers must also fit inside the mm cap.
                     else if (obj_layer_nr > 0 && node.support_roof_layers_below > 1 &&
-                             (node.dist_mm_to_top - this->top_z_distance) < top_interface_height + EPSILON && node.is_sharp_tail == false)
+                             node.is_sharp_tail == false)
                     {
-                        append(roof_areas, area);
+                        append(node.support_roof_layers_below <= top_base_interface_layers ? roof_base_areas : roof_areas, area);
                         max_layers_above_roof = std::max(max_layers_above_roof, node.dist_mm_to_top);
                     }
                     else
@@ -2184,9 +2176,17 @@ void TreeSupport::draw_circles()
                 //m_object->print()->set_status(65, (boost::format( _u8L("Support: generate polygons at layer %d")) % layer_nr).str());
 
                 // join roof segments
-                roof_areas     = diff_clipped(offset2_ex(roof_areas, line_width_scaled, -line_width_scaled), get_collision(false));
+                roof_areas     = diff_clipped(closing_ex(roof_areas, line_width_scaled), get_collision(false));
                 roof_areas     = intersection_ex(roof_areas, m_machine_border);
-                roof_1st_layer = diff_clipped(offset2_ex(roof_1st_layer, line_width_scaled, -line_width_scaled), get_collision(false));
+                roof_base_areas = diff_clipped(closing_ex(roof_base_areas, line_width_scaled), get_collision(false));
+                roof_base_areas = intersection_ex(roof_base_areas, m_machine_border);
+                if (!roof_base_areas.empty() && !roof_areas.empty())
+                    roof_base_areas = diff_ex(roof_base_areas,
+                        ClipperUtils::clip_clipper_polygons_with_subject_bbox(roof_areas, get_extents(roof_base_areas)));
+
+                first_base_roof_area = roof_areas.size();
+                append(roof_areas, std::move(roof_base_areas));
+                roof_1st_layer = diff_clipped(closing_ex(roof_1st_layer, line_width_scaled), get_collision(false));
 
                 // roof_1st_layer and roof_areas may intersect, so need to subtract roof_areas from roof_1st_layer
                 roof_1st_layer = diff_ex(roof_1st_layer, ClipperUtils::clip_clipper_polygons_with_subject_bbox(roof_areas,get_extents(roof_1st_layer)));
@@ -2366,9 +2366,11 @@ void TreeSupport::draw_circles()
                     area_groups.back().need_infill = overlaps({ expoly }, area_poly);
                     area_groups.back().need_extra_wall = need_extra_wall && !area_groups.back().need_infill;
                 }
-                for (auto& expoly : ts_layer->roof_areas) {
+                for (size_t roof_idx = 0; roof_idx < ts_layer->roof_areas.size(); ++roof_idx) {
+                    auto &expoly = ts_layer->roof_areas[roof_idx];
                     //if (area(expoly) < SQ(scale_(1))) continue;
                     area_groups.emplace_back(&expoly, SupportLayer::RoofType, max_layers_above_roof);
+                    area_groups.back().interface_as_base = roof_idx >= first_base_roof_area;
                 }
                 for (auto &expoly : ts_layer->floor_areas) {
                     //if (area(expoly) < SQ(scale_(1))) continue;
@@ -2378,6 +2380,7 @@ void TreeSupport::draw_circles()
                 for (auto &expoly : ts_layer->roof_1st_layer) {
                     //if (area(expoly) < SQ(scale_(1))) continue;
                     area_groups.emplace_back(&expoly, SupportLayer::Roof1stLayer, max_layers_above_roof1);
+                    area_groups.back().interface_as_base = top_base_interface_layers > 0;
                 }
 
                 for (auto &area_group : area_groups) {
@@ -2406,7 +2409,6 @@ void TreeSupport::draw_circles()
             }
         });
         // ORCA: normalize interface_id sequencing to follow printed interface layers only.
-        const int top_base_layers = int(m_support_params.num_top_base_interface_layers);
         const bool interlaced = m_object_config->support_interface_pattern == smipRectilinearInterlaced;
         int roof_interface_id = 0;
         int floor_interface_id = 0;
@@ -2425,7 +2427,6 @@ void TreeSupport::draw_circles()
                 if (area_group.type == SupportLayer::RoofType || area_group.type == SupportLayer::Roof1stLayer) {
                     if (interlaced)
                         area_group.interface_id = roof_interface_id;
-                    area_group.interface_as_base = top_base_layers > 0 && roof_interface_id < top_base_layers;
                     has_roof_interface = true;
                 } else if (area_group.type == SupportLayer::FloorType) {
                     if (interlaced)
@@ -2897,7 +2898,7 @@ void TreeSupport::drop_nodes()
                     node_parent->merged_neighbours.push_front(node_parent == p_node ? neighbour : p_node);
                     const bool to_buildplate = !is_inside_ex(get_collision(0, obj_layer_nr_next), next_position);
                     SupportNode* next_node = m_ts_data->create_node(next_position, node_parent->distance_to_top + 1, obj_layer_nr_next,
-                        node_parent->support_roof_layers_below - (node_parent->distance_to_top > 0 ? 1 : 0),
+                        node_parent->support_roof_layers_below - (node_parent->distance_to_top >= 0 ? 1 : 0),
                         to_buildplate, node_parent, print_z_next, height_next);
                     get_max_move_dist(next_node);
                     m_ts_data->m_mutex.lock();
@@ -2949,7 +2950,7 @@ void TreeSupport::drop_nodes()
                     for(auto& overhang:overhangs_next) {
                         Point        next_pt     = overhang.contour.centroid();
                         SupportNode *next_node   = m_ts_data->create_node(next_pt, p_node->distance_to_top + 1, obj_layer_nr_next,
-                                                                          p_node->support_roof_layers_below - (p_node->distance_to_top > 0 ? 1 : 0),
+                                                                          p_node->support_roof_layers_below - (p_node->distance_to_top >= 0 ? 1 : 0),
                                                                           to_buildplate, p_node, print_z_next, height_next);
                         next_node->max_move_dist = 0;
                         next_node->overhang = std::move(overhang);
@@ -3096,7 +3097,7 @@ void TreeSupport::drop_nodes()
                 auto              next_collision = get_collision(0, obj_layer_nr_next);
                 const bool   to_buildplate  = !is_inside_ex(m_ts_data->m_layer_outlines[obj_layer_nr_next], next_layer_vertex);
                 SupportNode *     next_node     = m_ts_data->create_node(next_layer_vertex, node.distance_to_top + 1, obj_layer_nr_next,
-                    node.support_roof_layers_below - (node.distance_to_top > 0 ? 1 : 0),
+                    node.support_roof_layers_below - (node.distance_to_top >= 0 ? 1 : 0),
                     to_buildplate, p_node, print_z_next, height_next);
                 // don't increase radius if next node will collide partially with the object (STUDIO-7883)
                 to_outside             = projection_onto(next_collision, next_node->position);
@@ -3376,21 +3377,6 @@ std::vector<LayerHeightData> TreeSupport::plan_layer_heights()
         }
     }
 
-    // ORCA: Recompute support_roof_layers_below from remaining interface height (independent heights).
-    const int top_layers = m_object->config().support_interface_top_layers.value;
-    if (m_support_params.independent_layer_height && top_layers > 0) {
-        const coordf_t interface_height_mm = coordf_t(top_layers) * m_slicing_params.layer_height;
-        for (int layer_nr = 0; layer_nr < contact_nodes.size(); layer_nr++) {
-            if (contact_nodes[layer_nr].empty()) continue;
-            for (SupportNode *node : contact_nodes[layer_nr]) {
-                if (node->height <= EPSILON) continue;
-                const coordf_t remaining_mm = interface_height_mm - (node->dist_mm_to_top - this->top_z_distance);
-                const int layers_fit = remaining_mm < -EPSILON ? 0 : int(std::floor((remaining_mm + EPSILON) / node->height));
-                node->support_roof_layers_below = std::min(layers_fit, top_layers);
-            }
-        }
-    }
-
     // log layer_heights
     for (size_t i = 0; i < layer_heights.size(); i++) {
         //if (layer_heights[i].height > EPSILON)
@@ -3498,7 +3484,7 @@ void TreeSupport::generate_contact_points()
                 if (force_add || !already_inserted.count(hash_pos)) {
                     already_inserted.emplace(hash_pos);
                     bool to_buildplate = true;
-                    size_t roof_layers = add_interface ? (support_roof_layers > 0 ? support_roof_layers - 1 : 0) : 0;  // subtract 1 because the contact node itself counts as one layer
+                    size_t roof_layers = add_interface ? support_roof_layers : 0;
                     // add a new node as a virtual node which acts as the invisible gap between support and object
                     // distance_to_top=-1: it's virtual
                     // print_z=object_layer->bottom_z: it directly contacts the bottom

src/libslic3r/Support/TreeSupport3D.cpp

@@ -706,7 +706,7 @@ static std::optional<std::pair<Point, size_t>> polyline_sample_next_point_at_dis
     filler->spacing  = flow.spacing();
     filler->angle = roof ?
         //fixme support_layer.interface_id() instead of layer_idx
-        (support_params.interface_angle + (layer_idx & 1) ? float(- M_PI / 4.) : float(+ M_PI / 4.)) :
+        (support_params.interface_angle + ((layer_idx & 1) ? float(- M_PI_4) : float(+ M_PI_4))) :
         support_params.base_angle;
 
     // ORCA: use top-specific interface density after separating top/bottom settings.

src/libslic3r/Support/TreeSupportCommon.hpp

@@ -62,7 +62,7 @@ struct TreeSupportMeshGroupSettings {
         this->support_line_width        = support_material_flow(&print_object, config.layer_height).scaled_width();
         this->support_roof_line_width   = support_material_interface_flow(&print_object, config.layer_height).scaled_width();
         const int bottom_interface_layers = number_of_support_interface_bottom_layers(config);
-        this->support_bottom_enable     = config.support_interface_top_layers.value > 0 && bottom_interface_layers > 0;
+        this->support_bottom_enable     = bottom_interface_layers > 0;
         this->support_bottom_height     = this->support_bottom_enable ?
             bottom_interface_layers * this->layer_height :
             0;
@@ -705,7 +705,7 @@ public:
     SupportGeneratorLayersPtr&  top_contacts_mutable() { return this->top_contacts; }
 
 public:
-    // Insert the contact layer and some of the inteface and base interface layers below.
+    // Insert the contact layer and some of the interface and base interface layers below.
     void add_roofs(std::vector<Polygons> &&new_roofs, const size_t insert_layer_idx)
     {
         if (! new_roofs.empty()) {

src/libslic3r/calib.hpp

@@ -42,10 +42,22 @@ struct Calib_Params
     std::string shaper_type;
     std::vector<double> accelerations;
     std::vector<double> speeds;
+    // Resolved layer height for the VFA tower (0 = auto: nozzle_diameter / 2). Each speed block is a
+    // fixed number of layers tall, so this also determines the physical block height / tower height.
+    double vfa_layer_height = 0.0;
+    // Scale the calibration model to the nozzle diameter and set the layer height accordingly (temp tower / VFA).
+    // When false the 0.4 mm / 0.2 mm reference model is printed as-is.
+    bool nozzle_based_resize = true;
 
     CalibMode mode;
 };
 
+// Number of printed layers per speed block in the VFA tower. The base model has 5 mm blocks designed
+// for a 0.2 mm layer height (0.4 mm nozzle), i.e. 25 layers per block.
+static constexpr int vfa_layers_per_block = 25;
+static constexpr double vfa_base_block_height = 5.0;
+static constexpr double vfa_base_nozzle_diameter = 0.4;
+
 enum FlowRatioCalibrationType {
     COMPLETE_CALIBRATION = 0,
     FINE_CALIBRATION,

src/libvgcode/include/Viewer.hpp

@@ -91,12 +91,15 @@ public:
     //
     void toggle_top_layer_only_view_range();
     //
-    // Dim previous layers (ORCA, ported from preFlight)
-    // Whether the layers below the current top layer are rendered darkened while
-    // scrubbing below the full print, so only the current layer is shown at full brightness.
+    // Dim previous layers (ORCA)
+    // Whether the layers the layer slider is not scrubbed to are rendered darkened while
+    // showing less than the full print, so only the inspected layer(s) are at full brightness.
+    // How bright those darkened layers are rendered, 1.0 = unchanged, 0.0 = black.
     //
     bool is_dim_previous_layers() const;
     void set_dim_previous_layers(bool value);
+    float get_dim_previous_layers_brightness() const;
+    void set_dim_previous_layers_brightness(float value);
     //
     // Returns true if the given option is visible.
     //

src/libvgcode/src/Settings.hpp

@@ -19,9 +19,11 @@ struct Settings
 		EViewType view_type{ EViewType::FeatureType };
 		ETimeMode time_mode{ ETimeMode::Normal };
 		bool top_layer_only_view_range{ false };
-		// ORCA: when enabled, all layers below the current top layer are rendered
-		// darkened (keeping their color) while scrubbing below the full print (ported from preFlight)
+		// ORCA: when enabled, every layer the layer slider is not scrubbed to is rendered
+		// darkened (keeping its color) while showing less than the full print
 		bool dim_previous_layers{ false };
+		// ORCA: how bright those darkened layers are rendered, 1.0 = unchanged, 0.0 = black
+		float dim_previous_layers_brightness{ 0.4f };
 		bool spiral_vase_mode{ false };
 		//
 		// Required update flags

src/libvgcode/src/Viewer.cpp

@@ -82,6 +82,16 @@ void Viewer::set_dim_previous_layers(bool value)
     m_impl->set_dim_previous_layers(value);
 }
 
+float Viewer::get_dim_previous_layers_brightness() const
+{
+    return m_impl->get_dim_previous_layers_brightness();
+}
+
+void Viewer::set_dim_previous_layers_brightness(float value)
+{
+    m_impl->set_dim_previous_layers_brightness(value);
+}
+
 bool Viewer::is_option_visible(EOptionType type) const
 {
     return m_impl->is_option_visible(type);

src/libvgcode/src/ViewerImpl.cpp

@@ -1223,16 +1223,12 @@ static float encode_color(const Color& color) {
     return static_cast<float>(i_color);
 }
 
-// ORCA: how much the layers below the current top layer are darkened when
-// Settings::dim_previous_layers is enabled (ported from preFlight). 0.0 = no change, 1.0 = black.
-static constexpr float PREVIOUS_LAYER_DARKEN_FACTOR = 0.60f;
-
-// ORCA: returns the encoded color scaled towards black by 'factor', preserving its hue
-static float encode_color_darkened(const Color& color, float factor) {
-    const float keep = 1.0f - factor;
-    const int r = static_cast<int>(color[0] * keep);
-    const int g = static_cast<int>(color[1] * keep);
-    const int b = static_cast<int>(color[2] * keep);
+// ORCA: returns the encoded color scaled towards black by 'brightness', preserving its hue.
+// 1.0 = no change, 0.0 = black.
+static float encode_color_dimmed(const Color& color, float brightness) {
+    const int r = static_cast<int>(color[0] * brightness);
+    const int g = static_cast<int>(color[1] * brightness);
+    const int b = static_cast<int>(color[2] * brightness);
     const int i_color = r << 16 | g << 8 | b;
     return static_cast<float>(i_color);
 }
@@ -1248,15 +1244,20 @@ void ViewerImpl::update_colors_texture()
     const size_t top_layer_id = m_settings.top_layer_only_view_range ? m_layers.get_view_range()[1] : 0;
     const bool color_top_layer_only = m_view_range.get_full()[1] != m_view_range.get_visible()[1];
 
-    // ORCA: when dim_previous_layers is enabled, darken every layer below the current top layer
-    // (keeping its color) whenever we are not rendering the whole print, so that only the layer
-    // being scrubbed to is shown at full brightness (ported from preFlight). This shares
-    // top_layer_id with the greying path, so it only applies while in top-layer-only mode - that
-    // way the moves slider still animates normally across all layers when that mode is disabled.
-    const bool dim_previous_layers = m_settings.dim_previous_layers && !m_layers.empty();
-    const bool full_render = (m_layers.get_view_range()[0] == 0) &&
-                             (m_layers.get_view_range()[1] >= static_cast<uint32_t>(m_layers.count()) - 1) &&
-                             (m_view_range.get_visible()[1] == m_view_range.get_full()[1]);
+    // ORCA: when dim_previous_layers is enabled, darken every layer (keeping its color) except the
+    // one(s) the layer slider is being scrubbed to, so that only those are shown at full brightness.
+    // A slider thumb marks a layer as inspected only once it is moved away from
+    // its end of the print: the upper one while it is below the last layer (or while the moves
+    // slider is not at the end of the layer), the lower one while it is above the first layer, so
+    // trimming the print from the bottom lights up the lowest visible layer and using the slider as
+    // a range lights up both ends. When neither thumb is moved the whole print is rendered normally.
+    // Gated on top-layer-only mode, which the greying path below also keys off of, so that the moves
+    // slider still animates normally across all layers when that mode is disabled.
+    const Interval& layers_range = m_layers.get_view_range();
+    const bool inspecting_top_layer = layers_range[1] + 1 < m_layers.count() || color_top_layer_only;
+    const bool inspecting_bottom_layer = layers_range[0] > 0;
+    const bool dim_previous_layers = m_settings.dim_previous_layers && m_settings.top_layer_only_view_range &&
+                                     !m_layers.empty() && (inspecting_top_layer || inspecting_bottom_layer);
 
     // Based on current settings and slider position, we might want to render some
     // vertices as dark grey (or darkened, see above). Use either that or the normal color (from the cache).
@@ -1265,9 +1266,13 @@ void ViewerImpl::update_colors_texture()
     for (size_t i=0; i<m_vertices.size(); ++i) {
         const PathVertex& v = m_vertices[i];
         const bool keep_spiral_seam = m_settings.spiral_vase_mode && i == m_view_range.get_enabled()[0];
-        if (dim_previous_layers && !full_render && v.layer_id < top_layer_id && !keep_spiral_seam)
-            colors[i] = encode_color_darkened(get_vertex_color(v), PREVIOUS_LAYER_DARKEN_FACTOR);
-        else if (color_top_layer_only && v.layer_id < top_layer_id && !keep_spiral_seam)
+        // ORCA: layers kept at full brightness by the dimming above are excluded from the greying below too
+        const bool inspected_layer = dim_previous_layers &&
+                                     ((inspecting_top_layer && v.layer_id == layers_range[1]) ||
+                                      (inspecting_bottom_layer && v.layer_id == layers_range[0]));
+        if (dim_previous_layers && !inspected_layer && !keep_spiral_seam)
+            colors[i] = encode_color_dimmed(get_vertex_color(v), m_settings.dim_previous_layers_brightness);
+        else if (!inspected_layer && color_top_layer_only && v.layer_id < top_layer_id && !keep_spiral_seam)
             colors[i] = encode_color(DUMMY_COLOR);
         else
             colors[i] = m_vertices_colors[i];
@@ -1379,7 +1384,7 @@ void ViewerImpl::toggle_top_layer_only_view_range()
     update_colors_texture();
 }
 
-// ORCA: enable/disable darkening of the layers below the current top layer (ported from preFlight)
+// ORCA: enable/disable darkening of the layers the layer slider is not scrubbed to
 void ViewerImpl::set_dim_previous_layers(bool value)
 {
     if (m_settings.dim_previous_layers == value)
@@ -1390,6 +1395,16 @@ void ViewerImpl::set_dim_previous_layers(bool value)
     m_settings.update_colors = true;
 }
 
+// ORCA: set how bright the darkened layers are rendered, 1.0 = unchanged, 0.0 = black
+void ViewerImpl::set_dim_previous_layers_brightness(float value)
+{
+    value = std::clamp(value, 0.0f, 1.0f);
+    if (m_settings.dim_previous_layers_brightness == value)
+        return;
+    m_settings.dim_previous_layers_brightness = value;
+    m_settings.update_colors = true;
+}
+
 std::vector<ETimeMode> ViewerImpl::get_time_modes() const
 {
     std::vector<ETimeMode> ret;

src/libvgcode/src/ViewerImpl.hpp

@@ -85,9 +85,14 @@ public:
     bool is_top_layer_only_view_range() const { return m_settings.top_layer_only_view_range; }
     void toggle_top_layer_only_view_range();
 
-    // ORCA: darken layers below the current top layer while scrubbing (ported from preFlight)
+    // ORCA: darken every layer the layer slider is not scrubbed to, so that only the inspected
+    // one(s) - the top thumb's layer, the bottom thumb's layer, or both - stay at full
+    // brightness. dim_previous_layers_brightness sets how dark the rest go, 1.0 = unchanged,
+    // 0.0 = black
     bool is_dim_previous_layers() const { return m_settings.dim_previous_layers; }
     void set_dim_previous_layers(bool value);
+    float get_dim_previous_layers_brightness() const { return m_settings.dim_previous_layers_brightness; }
+    void set_dim_previous_layers_brightness(float value);
 
     bool is_spiral_vase_mode() const { return m_settings.spiral_vase_mode; }
 

src/slic3r/CMakeLists.txt

@@ -752,6 +752,11 @@ set(SLIC3R_GUI_SOURCES
     Utils/WxFontUtils.hpp
     Utils/FileTransferUtils.cpp
     Utils/FileTransferUtils.hpp
+    Utils/wxInspectorPlugins/DPIAwarePlugin.hpp
+    Utils/wxInspectorPlugins/DPIAwarePlugin.cpp
+    Utils/wxInspectorPlugins/CustomWidgetsPlugin.hpp
+    Utils/wxInspectorPlugins/CustomWidgetsPlugin.cpp
+    Utils/wxInspectorPlugins/Registration.hpp
 )
 
 # Design/CAD tab: parametric sketch UI, its gizmo, and the MCP control socket.

src/slic3r/GUI/3DScene.cpp

@@ -70,6 +70,9 @@ float FullTransparentModdifiedToFixAlpha = 0.3f;
 // value like 0.18f could not because in C++ (int)(0.18f * 255) == 45 however in OpenGL it renders this as 46
 // which breaks the `SelectMachineDialog::record_edge_pixels_data()` function!
 float FULL_BLACK_THRESHOLD = 0.2f;
+// Keep depth_tex away from texture unit 0 to avoid sampler-type aliasing with
+// shadow/environment samplers when realistic view is disabled.
+static constexpr int OUTLINE_DEPTH_TEX_UNIT = 5;
 
 Slic3r::ColorRGBA adjust_color_for_rendering(const Slic3r::ColorRGBA &colors)
 {
@@ -518,6 +521,37 @@ void GLVolume::render_with_outline(const GUI::Size& cnv_size)
     glsafe(::glStencilMask(0xFF));
     glsafe(::glDisable(GL_STENCIL_TEST));
     // render the outline using depth buffer and discard the pixels that are not on the outline
+    // The silhouette is resolved per sample in the shader (see DetectSilho in gouraud.fs/phong.fs).
+    // That needs the GL 3.2 entry points and a shader that declares depth_tex as sampler2DMS, which
+    // only the 140 ones do and only under GL_ARB_texture_multisample - so ask the compiled program
+    // rather than the GL version, or a sampler2D ends up bound to a multisample texture.
+    // Only the Arb branch below allocates a multisample texture, so keep the target consistent with it.
+    const bool  use_msaa_outline = framebuffers_type == GUI::OpenGLManager::EFramebufferType::Arb &&
+                                   GUI::wxGetApp().is_gl_version_greater_or_equal_to(3, 2) &&
+                                   shader->get_uniform_location("msaa_samples") >= 0;
+    const GLenum depth_tex_target = use_msaa_outline ? GL_TEXTURE_2D_MULTISAMPLE : GL_TEXTURE_2D;
+    // Keep the depth texture off image unit 0. The object shaders leave shadow_map (and
+    // environment_tex) at the default sampler value 0 whenever the shadow pass is skipped - which is
+    // the case with realistic view off - and GL forbids two sampler types referring to the same image
+    // unit. A sampler2DMS on unit 0 then makes every draw fail with INVALID_OPERATION on drivers that
+    // enforce it (Mesa), i.e. the model disappears entirely. Unit 5 is unused (shadow_map takes 4).
+    const int depth_tex_unit = OUTLINE_DEPTH_TEX_UNIT;
+    int aa_samples = 1;
+    if (use_msaa_outline) {
+        if (const AppConfig* app_config = GUI::wxGetApp().app_config; app_config != nullptr) {
+            const std::string value = app_config->get(SETTING_OPENGL_AA_SAMPLES);
+            if (value == "2" || value == "4" || value == "8" || value == "16")
+                aa_samples = ::atoi(value.c_str());
+        }
+        // Never request more samples than the driver supports for depth textures (a 1-sample texture
+        // is used when MSAA is disabled, keeping a single code path for the sampler2DMS shader).
+        GLint max_samples = 1;
+        glsafe(::glGetIntegerv(GL_MAX_DEPTH_TEXTURE_SAMPLES, &max_samples));
+        if (aa_samples > max_samples)
+            aa_samples = max_samples < 1 ? 1 : max_samples;
+        if (aa_samples < 1)
+            aa_samples = 1;
+    }
     // 1st. render pass, render the model into a separate render target that has only depth buffer
     GLuint depth_fbo   = 0;
     GLuint depth_tex = 0;
@@ -525,21 +559,26 @@ void GLVolume::render_with_outline(const GUI::Size& cnv_size)
         glsafe(::glGenFramebuffers(1, &depth_fbo));
         glsafe(::glBindFramebuffer(GL_FRAMEBUFFER, depth_fbo));
 
-        glActiveTexture(GL_TEXTURE0);
+        glsafe(::glActiveTexture(GL_TEXTURE0 + depth_tex_unit));
         glsafe(::glGenTextures(1, &depth_tex));
-        glsafe(::glBindTexture(GL_TEXTURE_2D, depth_tex));
-        glsafe(::glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE));
-        glsafe(::glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE));
-        glsafe(::glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR));
-        glsafe(::glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR));
-        glsafe(::glTexImage2D(GL_TEXTURE_2D, 0, GL_DEPTH_COMPONENT32F, cnv_size.get_width(), cnv_size.get_height(), 0, GL_DEPTH_COMPONENT, GL_FLOAT, nullptr));
+        glsafe(::glBindTexture(depth_tex_target, depth_tex));
+        if (use_msaa_outline) {
+            // Multisample textures do not take filter/wrap parameters.
+            glsafe(::glTexImage2DMultisample(GL_TEXTURE_2D_MULTISAMPLE, aa_samples, GL_DEPTH_COMPONENT32F, cnv_size.get_width(), cnv_size.get_height(), GL_TRUE));
+        } else {
+            glsafe(::glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE));
+            glsafe(::glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE));
+            glsafe(::glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR));
+            glsafe(::glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR));
+            glsafe(::glTexImage2D(GL_TEXTURE_2D, 0, GL_DEPTH_COMPONENT32F, cnv_size.get_width(), cnv_size.get_height(), 0, GL_DEPTH_COMPONENT, GL_FLOAT, nullptr));
+        }
 
-        glsafe(::glFramebufferTexture2D(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_TEXTURE_2D, depth_tex, 0));
+        glsafe(::glFramebufferTexture2D(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, depth_tex_target, depth_tex, 0));
     } else {
         glsafe(::glGenFramebuffersEXT(1, &depth_fbo));
         glsafe(::glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, depth_fbo));
 
-        glActiveTexture(GL_TEXTURE0);
+        glsafe(::glActiveTexture(GL_TEXTURE0 + depth_tex_unit));
         glsafe(::glGenTextures(1, &depth_tex));
         glsafe(::glBindTexture(GL_TEXTURE_2D, depth_tex));
         glsafe(::glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE));
@@ -550,12 +589,15 @@ void GLVolume::render_with_outline(const GUI::Size& cnv_size)
 
         glsafe(::glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, GL_DEPTH_ATTACHMENT_EXT, GL_TEXTURE_2D, depth_tex, 0));
     }
+    // Unbind before drawing: the texture is this framebuffer's depth attachment, so leaving it bound
+    // to a sampled unit would be a feedback loop.
+    glsafe(::glBindTexture(depth_tex_target, 0));
+    glsafe(::glActiveTexture(GL_TEXTURE0));
     glsafe(::glClear(GL_DEPTH_BUFFER_BIT));
     if (tverts_range == std::make_pair<size_t, size_t>(0, -1))
         model.render(shader);
     else
         model.render(this->tverts_range, shader);
-    glsafe(::glBindTexture(GL_TEXTURE_2D, 0));
 
     // 2nd. render pass, just a normal render with the depth buffer passed as a texture
     if (framebuffers_type == GUI::OpenGLManager::EFramebufferType::Arb) {
@@ -565,13 +607,17 @@ void GLVolume::render_with_outline(const GUI::Size& cnv_size)
     }
     shader->set_uniform("is_outline", true);
     shader->set_uniform("screen_size", Vec2f{cnv_size.get_width(), cnv_size.get_height()});
-    glActiveTexture(GL_TEXTURE0);
-    glsafe(::glBindTexture(GL_TEXTURE_2D, depth_tex));
-    shader->set_uniform("depth_tex", 0);
+    shader->set_uniform("msaa_samples", aa_samples);
+    glsafe(::glActiveTexture(GL_TEXTURE0 + depth_tex_unit));
+    glsafe(::glBindTexture(depth_tex_target, depth_tex));
+    glsafe(::glActiveTexture(GL_TEXTURE0));
+    shader->set_uniform("depth_tex", depth_tex_unit);
     simple_render(shader, model_objects, colors);
 
     // Some clean up to do
-    glsafe(::glBindTexture(GL_TEXTURE_2D, 0));
+    glsafe(::glActiveTexture(GL_TEXTURE0 + depth_tex_unit));
+    glsafe(::glBindTexture(depth_tex_target, 0));
+    glsafe(::glActiveTexture(GL_TEXTURE0));
     shader->set_uniform("is_outline", false);
     if (framebuffers_type == GUI::OpenGLManager::EFramebufferType::Arb) {
         glsafe(::glBindFramebuffer(GL_FRAMEBUFFER, 0));
@@ -1075,6 +1121,10 @@ void GLVolumeCollection::render(GLVolumeCollection::ERenderType       type,
 
     const float support_normal_z = get_selection_support_normal_z();
 
+    // Prime depth_tex on every frame so non-outline draws do not keep the
+    // default sampler unit 0, which can conflict with other sampler types.
+    shader->set_uniform("depth_tex", OUTLINE_DEPTH_TEX_UNIT);
+
     for (GLVolumeWithIdAndZ& volume : to_render) {
 #if ENABLE_MODIFIERS_ALWAYS_TRANSPARENT
         if (type == ERenderType::Transparent) {

src/slic3r/GUI/AMSMaterialsSetting.cpp

@@ -4,6 +4,7 @@
 #include "GUI_App.hpp"
 #include "libslic3r/Preset.hpp"
 #include "I18N.hpp"
+#include <algorithm>
 #include <boost/log/trivial.hpp>
 #include <wx/colordlg.h>
 #include <wx/dcgraph.h>
@@ -1075,54 +1076,105 @@ void AMSMaterialsSetting::Popup(wxString filament, wxString sn, wxString temp_mi
 
     // Sort the filaments
     {
-        static std::unordered_map<wxString, int> sorted_names
-        {   {"Bambu PLA Basic",        0},
-            {"Bambu PLA Matte",        1},
-            {"Bambu PETG HF",          2},
-            {"Bambu ABS",              3},
-            {"Bambu PLA Silk",         4},
-            {"Bambu PLA-CF" ,          5},
-            {"Bambu PLA Galaxy",       6},
-            {"Bambu PLA Metal",        7},
-            {"Bambu PLA Marble",       8},
-            {"Bambu PETG-CF",          9},
-            {"Bambu PETG Translucent", 10},
-            {"Bambu ABS-GF",           11}
+        std::unordered_map<wxString, int> selected_filament_ranks;
+
+        // Helper lambda to find a filament Preset by name. We can call this multiple times to walk the inheritance chain and find the base filament.
+        auto find_filament_by_name = [](const std::string& wanted, const PresetCollection& filaments) -> const Preset* {
+            for (auto it = filaments.begin(); it != filaments.end(); ++it) {
+                if (it->name == wanted) {
+                    return &(*it);
+                }
+            }
+            return nullptr;
         };
 
-        static std::vector<wxString> sorted_vendors { "Bambu Lab", "Generic" };
-        static std::vector<wxString> sorted_types { "PLA", "PETG", "ABS", "TPU" };
-        auto _filament_sorter = [&query_filament_vendors, &query_filament_types](const wxString& left, const wxString& right) -> bool
-        {
-            { // Compare name order
-                const auto& iter1 = sorted_names.find(left);
-                int name_order1 = (iter1 != sorted_names.end()) ? iter1->second : INT_MAX;
+        // For each active filament preset, find its base filament alias and promote it in extruder order.
+        auto        bundle       = wxGetApp().preset_bundle;
+        const auto& preset_names = bundle->filament_presets;
+        for (size_t i = preset_names.size(); i-- > 0; ) {
+            std::string wanted = preset_names[i];
+            const int sort_rank = -static_cast<int>(preset_names.size() - i);
+            
+            const Preset* match = nullptr;
 
-                const auto& iter2 = sorted_names.find(right);
-                int name_order2 = (iter2 != sorted_names.end()) ? iter2->second : INT_MAX;
-                if (name_order1 != name_order2)
+            do {
+                auto find_result = find_filament_by_name(wanted, bundle->filaments);
+                if (!find_result) {
+                    BOOST_LOG_TRIVIAL(error) << __FUNCTION__ << " No available filament name matches " << wanted;
+                    break;
+                }
+
+                match = find_result;
+
+                BOOST_LOG_TRIVIAL(info) << __FUNCTION__ << " Found available filament matching current preset name " << wanted
+                                        << " - Name: " << match->name << " - Alias: " << match->alias
+                                        << " - Inherits: " << match->inherits();
+
+                if (match->inherits().length() == 0) {
+                    BOOST_LOG_TRIVIAL(info) << __FUNCTION__ << " No more inherits so we reached the base filament";
+                    break;
+                }
+
+                wanted = match->inherits();
+            } while (1); // Or loop while (match->alias.length() == 0) because existence of alias and inherits on a Preset seem to be exclusive
+
+            if (!match) {
+                continue;
+            }
+
+            BOOST_LOG_TRIVIAL(info) << __FUNCTION__ << " Update filament rank to " + std::to_string(sort_rank) + " for preset Name: "
+                                    << match->name << " - Alias: " << match->alias;
+            selected_filament_ranks.insert_or_assign(match->alias, sort_rank);
+        }
+        
+        static const std::vector<wxString> sorted_vendors { "Generic" };
+        static const std::vector<wxString> sorted_types { "PLA", "PETG", "ABS", "TPU" };
+        auto priority_rank = [](const std::vector<wxString>& priorities, const wxString& value) {
+            const auto iter = std::find_if(priorities.begin(), priorities.end(), [&value](const wxString& priority) {
+                return priority.CmpNoCase(value) == 0;
+            });
+            return iter - priorities.begin();
+        };
+        auto _filament_sorter = [&query_filament_vendors, &query_filament_types, &selected_filament_ranks, &priority_rank](const wxString& left, const wxString& right) -> bool
+        {
+            { // Compare selected filament order
+                const auto& iter1 = selected_filament_ranks.find(left);
+                int selected_order1 = (iter1 != selected_filament_ranks.end()) ? iter1->second : INT_MAX;
+
+                const auto& iter2 = selected_filament_ranks.find(right);
+                int selected_order2 = (iter2 != selected_filament_ranks.end()) ? iter2->second : INT_MAX;
+                if (selected_order1 != selected_order2)
                 {
-                    return name_order1 < name_order2;
+                    return selected_order1 < selected_order2;
                 }
             }
             { // Compare vendor
-                auto iter1 = std::find(sorted_vendors.begin(), sorted_vendors.end(), query_filament_vendors[left]);
-                auto iter2 = std::find(sorted_vendors.begin(), sorted_vendors.end(), query_filament_vendors[right]);
-                if (iter1 != iter2)
-                {
-                    return iter1 < iter2;
-                };
+                const wxString& vendor1 = query_filament_vendors.at(left);
+                const wxString& vendor2 = query_filament_vendors.at(right);
+                const auto      rank1   = priority_rank(sorted_vendors, vendor1);
+                const auto      rank2   = priority_rank(sorted_vendors, vendor2);
+                if (rank1 != rank2)
+                    return rank1 < rank2;
+
+                const int vendor_compare = vendor1.CmpNoCase(vendor2);
+                if (vendor_compare != 0)
+                    return vendor_compare < 0;
             }
             { // Compare type
-                auto iter1 = std::find(sorted_types.begin(), sorted_types.end(), query_filament_types[left]);
-                auto iter2 = std::find(sorted_types.begin(), sorted_types.end(), query_filament_types[right]);
-                if (iter1 != iter2)
-                {
-                    return iter1 < iter2;
-                }
+                const wxString& type1 = query_filament_types.at(left);
+                const wxString& type2 = query_filament_types.at(right);
+                const auto      rank1 = priority_rank(sorted_types, type1);
+                const auto      rank2 = priority_rank(sorted_types, type2);
+                if (rank1 != rank2)
+                    return rank1 < rank2;
+
+                const int type_compare = type1.CmpNoCase(type2);
+                if (type_compare != 0)
+                    return type_compare < 0;
             }
 
-            return left < right;
+            const int name_compare = left.CmpNoCase(right);
+            return name_compare != 0 ? name_compare < 0 : left < right;
         };
 
         std::sort(filament_items.begin(), filament_items.end(), _filament_sorter);

src/slic3r/GUI/BindDialog.cpp

@@ -192,7 +192,7 @@ PingCodeBindDialog::PingCodeBindDialog(Plater* plater /*= nullptr*/)
 
 
 
-    SetSizer(sizer_main);
+    SetSizerAndFit(sizer_main);
     Layout();
     Fit();
 
@@ -670,7 +670,7 @@ PingCodeBindDialog::~PingCodeBindDialog() {
      m_sizer_main->Add(m_sw_bind_failed_info, 0, wxALIGN_CENTER, 0);
      m_sizer_main->Add(m_simplebook, 0, wxALIGN_RIGHT | wxRIGHT | wxBOTTOM, ButtonProps::ChoiceButtonGap());
 
-     SetSizer(m_sizer_main);
+     SetSizerAndFit(m_sizer_main);
      Layout();
      Fit();
      Centre(wxBOTH);
@@ -992,7 +992,7 @@ UnBindMachineDialog::UnBindMachineDialog(Plater *plater /*= nullptr*/)
      m_sizer_main->Add(m_sizer_button, 0, wxALIGN_RIGHT | wxRIGHT, ButtonProps::ChoiceButtonGap());
      m_sizer_main->Add(0, 0, 0, wxTOP, FromDIP(20));
 
-     SetSizer(m_sizer_main);
+     SetSizerAndFit(m_sizer_main);
      Layout();
      Fit();
      Centre(wxBOTH);

src/slic3r/GUI/CaliHistoryDialog.cpp

@@ -632,9 +632,8 @@ EditCalibrationHistoryDialog::EditCalibrationHistoryDialog(wxWindow
 
     main_sizer->Add(top_panel, 1, wxEXPAND | wxALL, FromDIP(20));
 
-    SetSizer(main_sizer);
+    SetSizerAndFit(main_sizer);
     Layout();
-    Fit();
     CenterOnParent();
 
     wxGetApp().UpdateDlgDarkUI(this);
@@ -910,9 +909,8 @@ NewCalibrationHistoryDialog::NewCalibrationHistoryDialog(wxWindow *parent, const
 
     main_sizer->Add(top_panel, 1, wxEXPAND | wxALL, FromDIP(20));
 
-    SetSizer(main_sizer);
+    SetSizerAndFit(main_sizer);
     Layout();
-    Fit();
     CenterOnParent();
 
     wxGetApp().UpdateDlgDarkUI(this);

src/slic3r/GUI/Calibration.cpp

@@ -162,7 +162,7 @@ CalibrationDialog::CalibrationDialog(Plater *plater)
     body_panel->Layout();
 
     m_sizer_main->Add(body_panel, 0, wxEXPAND | wxALL, FromDIP(25));
-    SetSizer(m_sizer_main);
+    SetSizerAndFit(m_sizer_main);
     Layout();
     Fit();
 

src/slic3r/GUI/CloneDialog.cpp

@@ -112,9 +112,8 @@ CloneDialog::CloneDialog(wxWindow *parent)
 
     v_sizer->Add(bottom_sizer, 0, wxEXPAND);
 
-    this->SetSizer(v_sizer);
+    this->SetSizerAndFit(v_sizer);
     this->Layout();
-    v_sizer->Fit(this);
 
     wxGetApp().UpdateDlgDarkUI(this);
 

src/slic3r/GUI/ConfigManipulation.cpp

@@ -12,6 +12,7 @@
 #include "libslic3r/GCode/AdaptivePAProcessor.hpp"
 #include "Plater.hpp"
 
+#include <algorithm>
 #include <sstream>
 #include <wx/msgdlg.h>
 
@@ -70,6 +71,12 @@ void ConfigManipulation::toggle_line(const std::string& opt_key, const bool togg
         cb_toggle_line(opt_key, toggle, opt_index);
 }
 
+void ConfigManipulation::set_option_label(const std::string& opt_key, const wxString& label, int opt_index)
+{
+    if (cb_set_option_label)
+        cb_set_option_label(opt_key, label, opt_index);
+}
+
 void ConfigManipulation::check_nozzle_recommended_temperature_range(DynamicPrintConfig *config) {
     if (is_msg_dlg_already_exist)
         return;
@@ -244,6 +251,59 @@ void ConfigManipulation::check_chamber_minimal_temperature(DynamicPrintConfig* c
     }
 }
 
+void ConfigManipulation::layer_height_limits(double& min_layer_height, double& max_layer_height) const
+{
+    const DynamicPrintConfig& printer_config = GUI::wxGetApp().preset_bundle->printers.get_edited_preset().config;
+    const std::vector<double>& min_limits = printer_config.option<ConfigOptionFloats>("min_layer_height")->values;
+    const std::vector<double>& max_limits = printer_config.option<ConfigOptionFloats>("max_layer_height")->values;
+    min_layer_height = *std::min_element(min_limits.begin(), min_limits.end());
+    max_layer_height = *std::max_element(max_limits.begin(), max_limits.end());
+}
+
+bool ConfigManipulation::check_layer_height(DynamicPrintConfig* config)
+{
+    double min_layer_height = 0., max_layer_height = 0.;
+    layer_height_limits(min_layer_height, max_layer_height);
+    const double layer_height = config->opt_float("layer_height");
+
+    if (min_layer_height > EPSILON && layer_height < EPSILON) {
+        const wxString msg_text = wxString::Format(_L("Layer height is too small. It will be set to the minimum (%g mm)."), min_layer_height);
+        MessageDialog dialog(wxGetApp().plater(), msg_text, "", wxICON_WARNING | wxOK);
+        dialog.SetButtonLabel(wxID_OK, _L("OK"));
+        is_msg_dlg_already_exist = true;
+        dialog.ShowModal();
+        is_msg_dlg_already_exist = false;
+        DynamicPrintConfig new_conf = *config;
+        new_conf.set_key_value("layer_height", new ConfigOptionFloat(min_layer_height));
+        apply(config, &new_conf);
+        return true;
+    }
+    if (max_layer_height > EPSILON && layer_height > max_layer_height + EPSILON)
+        return layer_height_out_of_range_dialog(config, max_layer_height);
+    if (min_layer_height > EPSILON && layer_height < min_layer_height - EPSILON)
+        return layer_height_out_of_range_dialog(config, min_layer_height);
+    return false;
+}
+
+bool ConfigManipulation::layer_height_out_of_range_dialog(DynamicPrintConfig* config, double clamp_to)
+{
+    wxString msg_text = _(L("Layer height is outside the limits set in Printer Settings -> Extruder -> Layer height limits, "
+                            "this may cause printing quality issues."));
+    msg_text += "\n\n" + wxString::Format(_L("Adjust it to the limit (%g mm) automatically?"), clamp_to);
+    MessageDialog dialog(wxGetApp().plater(), msg_text, "", wxICON_WARNING | wxYES | wxNO);
+    dialog.SetButtonLabel(wxID_YES, _L("Adjust"));
+    dialog.SetButtonLabel(wxID_NO, _L("Ignore"));
+    is_msg_dlg_already_exist = true;
+    const bool adjust = dialog.ShowModal() == wxID_YES;
+    if (adjust) {
+        DynamicPrintConfig new_conf = *config;
+        new_conf.set_key_value("layer_height", new ConfigOptionFloat(clamp_to));
+        apply(config, &new_conf);
+    }
+    is_msg_dlg_already_exist = false;
+    return adjust;
+}
+
 void ConfigManipulation::update_print_fff_config(DynamicPrintConfig* config, const bool is_global_config, const bool is_plate_config)
 {
     // #ys_FIXME_to_delete
@@ -258,7 +318,6 @@ void ConfigManipulation::update_print_fff_config(DynamicPrintConfig* config, con
 
     // layer_height shouldn't be equal to zero
     auto layer_height = config->opt_float("layer_height");
-    auto gpreset = GUI::wxGetApp().preset_bundle->printers.get_edited_preset();
     if (layer_height < EPSILON)
     {
         const wxString msg_text = _(L("Layer height too small\nIt has been reset to 0.2"));
@@ -271,20 +330,6 @@ void ConfigManipulation::update_print_fff_config(DynamicPrintConfig* config, con
         is_msg_dlg_already_exist = false;
     }
 
-    //BBS: limite the max layer_herght
-    auto max_lh = gpreset.config.opt_float("max_layer_height",0);
-    if (max_lh > 0.2 && layer_height > max_lh+ EPSILON)
-    {
-        const wxString msg_text = wxString::Format(L"Too large layer height.\nReset to %0.3f.", max_lh);
-        MessageDialog dialog(nullptr, msg_text, "", wxICON_WARNING | wxOK);
-        DynamicPrintConfig new_conf = *config;
-        is_msg_dlg_already_exist = true;
-        dialog.ShowModal();
-        new_conf.set_key_value("layer_height", new ConfigOptionFloat(max_lh));
-        apply(config, &new_conf);
-        is_msg_dlg_already_exist = false;
-    }
-
     //BBS: ironing_spacing shouldn't be too small or equal to zero
     if (config->opt_float("ironing_spacing") < 0.05)
     {
@@ -703,12 +748,14 @@ void ConfigManipulation::toggle_print_fff_options(DynamicPrintConfig *config, in
     toggle_line("spiral_mode_max_xy_smoothing", has_spiral_vase && config->opt_bool("spiral_mode_smooth"));
     toggle_line("spiral_starting_flow_ratio", has_spiral_vase);
     toggle_line("spiral_finishing_flow_ratio", has_spiral_vase);
-    bool has_top_shell    = config->opt_int("top_shell_layers") > 0 || (has_spiral_vase && config->opt_int("bottom_shell_layers") > 1);
+    bool has_top_shell_layers = config->opt_int("top_shell_layers") > 0 || (has_spiral_vase && config->opt_int("bottom_shell_layers") > 1);
+    bool has_top_shell    = has_top_shell_layers && config->option<ConfigOptionPercent>("top_surface_density")->value > 0;
     bool has_bottom_shell = config->opt_int("bottom_shell_layers") > 0;
-    bool has_solid_infill = has_top_shell || has_bottom_shell;
+    bool has_solid_infill = has_top_shell_layers || has_bottom_shell;
+    toggle_line("sparse_infill_smooth_factor", pattern == ipHilbertCurve);
     toggle_field("top_surface_pattern", has_top_shell);
     toggle_field("bottom_surface_pattern", has_bottom_shell);
-    toggle_field("top_surface_density", has_top_shell);
+    toggle_field("top_surface_density", has_top_shell_layers);
     toggle_field("bottom_surface_density", has_bottom_shell);
     toggle_field("top_layer_direction", has_top_shell);
     toggle_field("bottom_layer_direction", has_bottom_shell);
@@ -751,7 +798,7 @@ void ConfigManipulation::toggle_print_fff_options(DynamicPrintConfig *config, in
     for (auto el : { "sparse_infill_speed", "bridge_speed", "internal_bridge_speed"})
         toggle_field(el, have_infill || has_solid_infill, variant_index);
 
-    toggle_field("top_shell_thickness", ! has_spiral_vase && has_top_shell);
+    toggle_field("top_shell_thickness", ! has_spiral_vase && has_top_shell_layers);
     toggle_field("bottom_shell_thickness", ! has_spiral_vase && has_bottom_shell);
 
     // Gap fill is newly allowed in between perimeter lines even for empty infill (see GH #1476).
@@ -806,14 +853,19 @@ void ConfigManipulation::toggle_print_fff_options(DynamicPrintConfig *config, in
     toggle_field("outer_wall_filament_id", have_perimeters || have_brim);
     toggle_field("inner_wall_filament_id", have_perimeters || have_brim);
 
-    bool have_brim_ear = (config->opt_enum<BrimType>("brim_type") == btEar);
+    const BrimType brim_type = config->opt_enum<BrimType>("brim_type");
+    const bool have_auto_brim_ear = brim_type == btEar;
+    const bool have_painted_brim_ear = brim_type == btPainted;
+    set_option_label("brim_width", have_auto_brim_ear ? _L("Brim ear radius") : _L("Brim width"));
     const auto brim_width = config->opt_float("brim_width");
-    // disable brim_ears_max_angle and brim_ears_detection_length if brim_width is 0
+    // Automatic brim ear settings require a non-zero brim width.
     toggle_field("brim_ears_max_angle", brim_width > 0.0f);
     toggle_field("brim_ears_detection_length", brim_width > 0.0f);
-    // hide brim_ears_max_angle and brim_ears_detection_length if brim_ear is not selected
-    toggle_line("brim_ears_max_angle", have_brim_ear);
-    toggle_line("brim_ears_detection_length", have_brim_ear);
+    // Painted ears carry their own radius and do not depend on brim_width.
+    toggle_field("brim_ears_outer_only", have_painted_brim_ear || brim_width > 0.0f);
+    toggle_line("brim_ears_max_angle", have_auto_brim_ear);
+    toggle_line("brim_ears_detection_length", have_auto_brim_ear);
+    toggle_line("brim_ears_outer_only", have_auto_brim_ear || have_painted_brim_ear);
 
     // Hide Elephant foot compensation layers if elefant_foot_compensation is not enabled
     toggle_line("elefant_foot_compensation_layers", config->opt_float("elefant_foot_compensation") > 0 || config->option<ConfigOptionPercent>("elefant_foot_layers_density")->get_abs_value(1.0f) < 1.0f);
@@ -1008,7 +1060,11 @@ void ConfigManipulation::toggle_print_fff_options(DynamicPrintConfig *config, in
     toggle_line("make_overhang_printable_angle", have_make_overhang_printable);
     toggle_line("make_overhang_printable_hole_size", have_make_overhang_printable);
 
-    toggle_line("min_width_top_surface", config->opt_bool("only_one_wall_top") || ((config->opt_float("min_length_factor") > 0.5f) && have_arachne)); // 0.5 is default value
+    // Orca: the one-wall options act on top/bottom surfaces, which exist only with a shell. An unfilled surface
+    // (0% surface density) is still a surface, so these are gated on the layer counts alone.
+    toggle_line("only_one_wall_first_layer", has_bottom_shell);
+    toggle_line("only_one_wall_top", has_top_shell_layers);
+    toggle_line("min_width_top_surface", (has_top_shell_layers && config->opt_bool("only_one_wall_top")) || ((config->opt_float("min_length_factor") > 0.5f) && have_arachne)); // 0.5 is default value
 
     for (auto el : { "hole_to_polyhole_threshold", "hole_to_polyhole_twisted", "hole_to_polyhole_max_edges" })
         toggle_line(el, config->opt_bool("hole_to_polyhole"));

src/slic3r/GUI/ConfigManipulation.hpp

@@ -29,6 +29,7 @@ class ConfigManipulation
     std::function<void()>                                       load_config = nullptr;
     std::function<void (const std::string&, bool toggle, int opt_index)>   cb_toggle_field = nullptr;
     std::function<void(const std::string &, bool toggle, int opt_index)> cb_toggle_line  = nullptr;
+    std::function<void(const std::string &, const wxString &, int opt_index)> cb_set_option_label = nullptr;
     // callback to propagation of changed value, if needed
     std::function<void(const std::string&, const boost::any&)>  cb_value_change = nullptr;
     //BBS: change local config to const DynamicPrintConfig
@@ -45,10 +46,12 @@ public:
         std::function<void(const std::string&, const boost::any&)>  cb_value_change,
         //BBS: change local config to DynamicPrintConfig
         const DynamicPrintConfig* local_config = nullptr,
-        wxWindow* msg_dlg_parent  = nullptr) :
+        wxWindow* msg_dlg_parent  = nullptr,
+        std::function<void(const std::string &, const wxString &, int opt_index)> cb_set_option_label = nullptr) :
         load_config(load_config),
         cb_toggle_field(cb_toggle_field),
         cb_toggle_line(cb_toggle_line),
+        cb_set_option_label(cb_set_option_label),
         cb_value_change(cb_value_change),
         m_msg_dlg_parent(msg_dlg_parent),
         local_config(local_config) {}
@@ -58,6 +61,7 @@ public:
         load_config = nullptr;
         cb_toggle_field = nullptr;
         cb_toggle_line = nullptr;
+        cb_set_option_label = nullptr;
         cb_value_change = nullptr;
     }
 
@@ -67,6 +71,7 @@ public:
     t_config_option_keys const &applying_keys() const;
     void    toggle_field(const std::string& field_key, const bool toggle, int opt_index = -1);
     void    toggle_line(const std::string& field_key, const bool toggle, int opt_index = -1);
+    void    set_option_label(const std::string& field_key, const wxString& label, int opt_index = -1);
 
     // FFF print
     void    update_print_fff_config(DynamicPrintConfig* config, const bool is_global_config = false, const bool is_plate_config = false);
@@ -81,6 +86,9 @@ public:
     void    check_filament_max_volumetric_speed(DynamicPrintConfig *config);
     void    check_chamber_temperature(DynamicPrintConfig* config);
     void    check_chamber_minimal_temperature(DynamicPrintConfig* config);
+    bool    check_layer_height(DynamicPrintConfig* config);
+    bool    layer_height_out_of_range_dialog(DynamicPrintConfig* config, double clamp_to);
+    void    layer_height_limits(double& min_layer_height, double& max_layer_height) const;
     void    set_is_BBL_Printer(bool is_bbl_printer) { is_BBL_Printer = is_bbl_printer; };
     bool    get_is_BBL_Printer() { return is_BBL_Printer; };
     // SLA print

src/slic3r/GUI/ConnectPrinter.cpp

@@ -80,9 +80,8 @@ ConnectPrinterDialog::ConnectPrinterDialog(wxWindow *parent, wxWindowID id, cons
 
     main_sizer->Add(sizer_top);
 
-    this->SetSizer(main_sizer);
+    this->SetSizerAndFit(main_sizer);
     this->Layout();
-    this->Fit();
     CentreOnParent();
 
     m_textCtrl_code->Bind(wxEVT_TEXT, &ConnectPrinterDialog::on_input_enter, this);
@@ -157,6 +156,8 @@ void ConnectPrinterDialog::on_input_enter(wxCommandEvent& evt)
 void ConnectPrinterDialog::on_button_confirm(wxCommandEvent &event)
 {
     wxString code = m_textCtrl_code->GetTextCtrl()->GetValue();
+    if (code.empty())
+        code = "88888888";
     for (char c : code) {
         if (!(('0' <= c && c <= '9') || ('a' <= c && c <= 'z') || ('A' <= c && c <= 'Z'))) {
             show_error(this, _L("Invalid input"));
@@ -164,7 +165,7 @@ void ConnectPrinterDialog::on_button_confirm(wxCommandEvent &event)
         }
     }
     if (m_obj) {
-        m_obj->set_user_access_code(code.ToStdString());
+        m_obj->set_access_code(code.ToStdString());
     }
     EndModal(wxID_OK);
 }

src/slic3r/GUI/DeviceCore/DevManager.cpp

@@ -15,6 +15,18 @@
 
 using namespace nlohmann;
 
+namespace {
+    // Orca: access_code and user_access_code used to be separate AppConfig keys before the two
+    // fields were merged; fall back to the legacy key so existing users' saved codes aren't lost.
+    std::string get_access_code_with_legacy_fallback(Slic3r::AppConfig* config, const std::string& dev_id)
+    {
+        std::string code = config->get("access_code", dev_id);
+        if (code.empty())
+            code = config->get("user_access_code", dev_id);
+        return code;
+    }
+}
+
 namespace Slic3r
 {
     DeviceManager::DeviceManager(NetworkAgent* agent)
@@ -48,8 +60,7 @@ namespace Slic3r
             obj->bind_sec_link       = "secure";
             obj->m_is_online         = true;
             obj->last_alive          = Slic3r::Utils::get_current_time_utc();
-            obj->set_access_code(config->get("access_code", m.dev_id), false);
-            obj->set_user_access_code(config->get("user_access_code", m.dev_id), false);
+            obj->set_access_code(get_access_code_with_legacy_fallback(config, m.dev_id), false);
             if (obj->has_access_right()) {
                 localMachineList.insert(std::make_pair(m.dev_id, obj));
             } else {
@@ -339,8 +350,7 @@ namespace Slic3r
                 //load access code
                 AppConfig* config = Slic3r::GUI::wxGetApp().app_config;
                 if (config) {
-                    obj->set_access_code(Slic3r::GUI::wxGetApp().app_config->get("access_code", dev_id), false);
-                    obj->set_user_access_code(Slic3r::GUI::wxGetApp().app_config->get("user_access_code", dev_id), false);
+                    obj->set_access_code(get_access_code_with_legacy_fallback(config, dev_id), false);
                 }
                 localMachineList.insert(std::make_pair(dev_id, obj));
 
@@ -382,7 +392,6 @@ namespace Slic3r
         obj->m_is_online = true;
         obj->last_alive = Slic3r::Utils::get_current_time_utc();
         obj->set_access_code(access_code, false);
-        obj->set_user_access_code(access_code, false);
 
         update_local_machine(*obj);
 
@@ -496,6 +505,26 @@ namespace Slic3r
         OnSelectedMachineChanged(previous_selected_machine, selected_machine);
     }
 
+    void DeviceManager::clear_other_devices()
+    {
+        // why: on agent swap, keep "My Devices" but drop the transient "Other Devices"
+        // Those belong to the previous agent's network scan; the new agent's start_discovery re-populates its own.
+        const auto my = get_my_machine_list();
+        for (auto it = localMachineList.begin(); it != localMachineList.end();)
+        {
+            if (my.find(it->first) == my.end())
+            {
+                // not a "My Device" -> an "Other Device"
+                delete it->second;
+                it = localMachineList.erase(it);
+            }
+            else
+            {
+                ++it;
+            }
+        }
+    }
+
     bool DeviceManager::set_selected_machine(std::string dev_id)
     {
         BOOST_LOG_TRIVIAL(info) << "set_selected_machine=" << dev_id
@@ -558,7 +587,6 @@ namespace Slic3r
             }
             else
             {
-                Slic3r::GUI::wxGetApp().reset_unsigned_plugin_warning();
                 if (m_agent)
                 {
                     if (it->second->connection_type() != "lan" || it->second->connection_type().empty())
@@ -851,7 +879,9 @@ namespace Slic3r
         int result = m_agent->get_user_print_info(&http_code, &body, provider);
         if (result == 0)
         {
-            parse_user_print_info(body);
+            // parse_user_print_info and on_machine_alive (SSDP for discovery) both mutate the same userMachineList map.
+            // on_machine_alive mutates the map on the UI thread, do the same for parse_user_print_info.
+            Slic3r::GUI::wxGetApp().CallAfter([this, body]() { parse_user_print_info(body); });
         }
     }
 
@@ -878,17 +908,15 @@ namespace Slic3r
 
     void DeviceManager::load_last_machine()
     {
-        if (userMachineList.empty()) return;
-        else if (userMachineList.size() == 1) {
-            this->set_selected_machine(userMachineList.begin()->second->get_dev_id());
-        } else {
-            const auto& last_monitor_machine = get_user_last_machine();
-            if (userMachineList.find(last_monitor_machine) != userMachineList.end()) {
-                set_selected_machine(last_monitor_machine);
-            } else {
-                this->set_selected_machine(userMachineList.begin()->second->get_dev_id());
-            }
-        }
+        // Only reconnect the remembered cloud machine. Do not select an arbitrary
+        // first machine: agent swaps intentionally leave the selection empty until
+        // the new agent explicitly selects its configured printer.
+        if (userMachineList.empty())
+            return;
+
+        const auto& last_monitor_machine = get_user_last_machine();
+        if (userMachineList.find(last_monitor_machine) != userMachineList.end())
+            set_selected_machine(last_monitor_machine);
     }
 
     void DeviceManager::OnMachineBindStateChanged(MachineObject* obj, const std::string& new_state)

src/slic3r/GUI/DeviceCore/DevManager.h

@@ -48,6 +48,10 @@ public:
     MachineObject* get_selected_machine();
     bool set_selected_machine(std::string dev_id);
 
+    // why: clears stale sidebar sync-status / AMS visuals. Public so the printer-agent
+    // swap path can reuse it instead of duplicating the two sidebar calls.
+    void OnSelectedMachineLost();
+
     void record_user_last_machine(const std::string& dev_id);
     std::string get_user_last_machine() const;
 
@@ -70,6 +74,8 @@ public:
     void erase_user_machine(std::string dev_id) { userMachineList.erase(dev_id); }
     void clean_user_info(bool keep_local_selection = false);
 
+    void clear_other_devices();
+
     void load_last_machine();
     void update_user_machine_list_info(const std::string& provider);
     void parse_user_print_info(std::string body);
@@ -110,7 +116,6 @@ private:
     void check_pushing();
 
     void OnMachineBindStateChanged(MachineObject* obj, const std::string& new_state);
-    void OnSelectedMachineLost();
     void OnSelectedMachineChanged(const std::string& pre_dev_id, const std::string& new_dev_id);
 
 

src/slic3r/GUI/DeviceCore/DevUtil.h

@@ -13,6 +13,7 @@
 
 #include <boost/log/trivial.hpp>
 #include <boost/lexical_cast.hpp>
+#include <boost/format.hpp>
 
 #include "nlohmann/json.hpp"
 

src/slic3r/GUI/DeviceManager.cpp

@@ -449,9 +449,7 @@ bool MachineObject::HasRecentLanMessage()
 
 std::string MachineObject::get_access_code() const
 {
-    if (get_user_access_code().empty())
-        return access_code;
-    return get_user_access_code();
+    return access_code;
 }
 
 void MachineObject::set_access_code(std::string code, bool only_refresh)
@@ -470,37 +468,6 @@ void MachineObject::set_access_code(std::string code, bool only_refresh)
     }
 }
 
-void MachineObject::erase_user_access_code()
-{
-    this->user_access_code = "";
-    AppConfig* config = GUI::wxGetApp().app_config;
-    if (config) {
-        GUI::wxGetApp().app_config->erase("user_access_code", get_dev_id());
-        //GUI::wxGetApp().app_config->save();
-    }
-}
-
-void MachineObject::set_user_access_code(std::string code, bool only_refresh)
-{
-    this->user_access_code = code;
-    if (only_refresh && !code.empty()) {
-        AppConfig* config = GUI::wxGetApp().app_config;
-        if (config && !code.empty()) {
-            GUI::wxGetApp().app_config->set_str("user_access_code", get_dev_id(), code);
-            DeviceManager::update_local_machine(*this);
-        }
-    }
-}
-
-std::string MachineObject::get_user_access_code() const
-{
-    AppConfig* config = GUI::wxGetApp().app_config;
-    if (config) {
-        return GUI::wxGetApp().app_config->get("user_access_code", get_dev_id());
-    }
-    return "";
-}
-
 std::string MachineObject::get_show_printer_type() const
 {
     std::string printer_type = this->printer_type;
@@ -2907,7 +2874,6 @@ int MachineObject::parse_json(std::string tunnel, std::string payload, bool key_
                         std::string access_code = j_pre["system"]["access_code"].get<std::string>();
                         if (!access_code.empty()) {
                             set_access_code(access_code);
-                            set_user_access_code(access_code);
                         }
                     }
                 }
@@ -4647,6 +4613,40 @@ void MachineObject::set_ctt_dlg( wxString text){
     }
 }
 
+void MachineObject::show_unsupported_dlg(int code)
+{
+    // why: a dead control invites repeat clicks, and the frame is modeless - without the guard
+    // every click stacks another one. Same shape as set_ctt_dlg above, including the reset on
+    // both hide and close so a dismissed dialog can reappear on the next attempt.
+    if (m_unsupported_dlg_shown) {
+        return;
+    }
+    m_unsupported_dlg_shown = true;
+
+    // why: two codes so the user learns which kind of dead end this is - the slicer having no
+    // translation for the command, or the printer's own config lacking the hardware to run it.
+    const wxString text = (code == ORCA_NETWORK_ERR_CAP_NOT_AVAILABLE) ?
+                              _L("This printer is not configured with the hardware this control needs.") :
+                              _L("This control is not supported on this printer.");
+
+    // note: constructed directly rather than through CallAfter because every publish_json caller
+    // is on the UI thread - clicks come from wx handlers, and the agent marshals its own push
+    // callbacks back to main before parse_json runs. set_ctt_dlg relies on the same property.
+    auto unsupported_dlg = new GUI::SecondaryCheckDialog(nullptr, wxID_ANY, _L("Warning"),
+                                                         GUI::SecondaryCheckDialog::VisibleButtons::ONLY_CONFIRM);
+    unsupported_dlg->update_text(text);
+    unsupported_dlg->Bind(wxEVT_SHOW, [this](auto& e) {
+        if (!e.IsShown()) {
+            m_unsupported_dlg_shown = false;
+        }
+        });
+    unsupported_dlg->Bind(wxEVT_CLOSE_WINDOW, [this](auto& e) {
+        e.Skip();
+        m_unsupported_dlg_shown = false;
+        });
+    unsupported_dlg->on_show();
+}
+
 int MachineObject::publish_gcode(std::string gcode_str)
 {
     json j;

src/slic3r/GUI/DeviceManager.hpp

@@ -113,7 +113,6 @@ private:
     std::string dev_name;
     std::string dev_ip;
     std::string access_code;
-    std::string user_access_code;
 
     // type, time stamp, delay
     std::vector<std::tuple<std::string, uint64_t, uint64_t>> message_delay;
@@ -228,11 +227,6 @@ public:
     std::string get_access_code() const;
     void set_access_code(std::string code, bool only_refresh = true);
 
-    /*user access code*/
-    void set_user_access_code(std::string code, bool only_refresh = true);
-    void erase_user_access_code();
-    std::string get_user_access_code() const;
-
     //PRINTER_TYPE printer_type = PRINTER_3DPrinter_UKNOWN;
     std::string printer_type;       /* model_id */
     std::string   get_show_printer_type() const;
@@ -272,9 +266,11 @@ public:
     bool m_is_online;
     bool m_lan_mode_connection_state{false};
     bool m_set_ctt_dlg{ false };
+    bool m_unsupported_dlg_shown{ false };
     void set_lan_mode_connection_state(bool state) {m_lan_mode_connection_state = state;};
     bool get_lan_mode_connection_state() {return m_lan_mode_connection_state;};
     void set_ctt_dlg( wxString text);
+    void show_unsupported_dlg(int code);
     int  parse_msg_count = 0;
     int  keep_alive_count = 0;
     std::chrono::system_clock::time_point   last_update_time;   /* last received print data from machine */

src/slic3r/GUI/DeviceTab/uiAmsHumidityPopup.cpp

@@ -1,9 +1,9 @@
-//**********************************************************/
-/* File: uiAmsHumidityPopup.cpp
+/**********************************************************
+* File: uiAmsHumidityPopup.cpp
 *  Description: The popup with DevAms Humidity
 *
 * \n class uiAmsHumidityPopup
-//**********************************************************/
+**********************************************************/
 
 #include "uiAmsHumidityPopup.h"
 
@@ -191,4 +191,4 @@ void uiAmsPercentHumidityDryPopup::msw_rescale()
 
 } // namespace GUI
 
-} // namespace Slic3r
+} // namespace Slic3r

src/slic3r/GUI/DeviceTab/uiAmsHumidityPopup.h

@@ -1,9 +1,9 @@
-//**********************************************************/
-/* File: uiAmsHumidityPopup.h
+/**********************************************************
+* File: uiAmsHumidityPopup.h
 *  Description: The popup with DevAms Humidity
 *
 *  \n class uiAmsHumidityPopup
-//**********************************************************/
+**********************************************************/
 
 #pragma once
 #include "slic3r/GUI/Widgets/AMSItem.hpp"
@@ -68,7 +68,7 @@ private:
 
     wxStaticBitmap* m_dry_state_img;
     Label*          m_dry_state;
-    
+
     Label* m_humidity_header;
     Label* m_humidity_label;
 
@@ -81,4 +81,4 @@ private:
     wxSizer*       m_sizer;
 };
 
-}} // namespace Slic3r::GUI
+}} // namespace Slic3r::GUI

src/slic3r/GUI/DeviceTab/uiDeviceUpdateVersion.cpp

@@ -1,9 +1,9 @@
-//**********************************************************/
-/* File: uiDeviceUpdateVersion.cpp
+/**********************************************************
+* File: uiDeviceUpdateVersion.cpp
 *  Description: The panel with firmware info
 *
 * \n class uiDeviceUpdateVersion
-//**********************************************************/
+**********************************************************/
 
 #include "uiDeviceUpdateVersion.h"
 
@@ -114,4 +114,4 @@ void uiDeviceUpdateVersion::CreateWidgets()
     Layout();
 
     wxGetApp().UpdateDarkUIWin(this);
-}
+}

src/slic3r/GUI/DeviceTab/uiDeviceUpdateVersion.h

@@ -1,9 +1,9 @@
-//**********************************************************/
-/* File: uiDeviceUpdateVersion.h
+/**********************************************************
+* File: uiDeviceUpdateVersion.h
 *  Description: The panel with firmware info
 * 
 *  \n class uiDeviceUpdateVersion
-//**********************************************************/
+**********************************************************/
 
 #pragma once
 #include <wx/panel.h>
@@ -44,4 +44,4 @@ private:
     wxStaticText*   m_dev_version;
     wxStaticBitmap* m_dev_upgrade_indicator;
 };
-};// end of namespace Slic3r::GUI
+};// end of namespace Slic3r::GUI

src/slic3r/GUI/DownloadProgressDialog.cpp

@@ -112,9 +112,8 @@ DownloadProgressDialog::DownloadProgressDialog(wxString title)
     m_simplebook_status->AddPage(m_panel_download_failed, wxEmptyString, false);
     m_simplebook_status->AddPage(m_panel_install_failed, wxEmptyString, false);
 
-    SetSizer(m_sizer_main);
+    SetSizerAndFit(m_sizer_main);
     Layout();
-    Fit();
     CentreOnParent();
 
     Bind(wxEVT_CLOSE_WINDOW, &DownloadProgressDialog::on_close, this);

src/slic3r/GUI/ExtrusionCalibration.cpp

@@ -261,7 +261,7 @@ void ExtrusionCalibration::create()
     top_sizer->Add(FromDIP(24), 0);
     top_sizer->Add(sizer_main, 1, wxEXPAND);
     top_sizer->Add(FromDIP(24), 0);
-    SetSizer(top_sizer);
+    SetSizerAndFit(top_sizer);
 
     // set default nozzle
     m_comboBox_nozzle_dia->SetSelection(1);
@@ -271,7 +271,6 @@ void ExtrusionCalibration::create()
     set_step(1);
 
     Layout();
-    Fit();
 
     m_k_val->GetTextCtrl()->Bind(wxEVT_TEXT_ENTER, [this](wxCommandEvent& e) {
         input_value_finish();

src/slic3r/GUI/Field.cpp

@@ -35,6 +35,7 @@
 #include "Widgets/TextCtrl.h"
 
 #include "../Utils/ColorSpaceConvert.hpp"
+#include "../Utils/NetworkAgentFactory.hpp"
 #ifdef __WXOSX__
 #define wxOSX true
 #else
@@ -1334,27 +1335,7 @@ void SpinCtrl::BUILD() {
         if (!parsed || value < INT_MIN || value > INT_MAX)
             tmp_value = UNDEF_VALUE;
         else {
-            tmp_value = std::min(std::max((int)value, temp->GetMin()), temp->GetMax());
-#ifdef __WXOSX__
-#ifdef UNDEFINED__WXOSX__ // BBS
-            // Forcibly set the input value for SpinControl, since the value
-            // inserted from the keyboard or clipboard is not updated under OSX
-            SpinInput* spin = static_cast<SpinInput*>(window);
-            spin->SetValue(tmp_value);
-            // But in SetValue() is executed m_text_ctrl->SelectAll(), so
-            // discard this selection and set insertion point to the end of string
-            // temp->GetText()->SetInsertionPointEnd();
-#endif
-#else
-            // update value for the control only if it was changed in respect to the Min/max values
-            if (tmp_value != (int)value) {
-                temp->SetValue(tmp_value);
-                // But after SetValue() cursor ison the first position
-                // so put it to the end of string
-                // int pos = std::to_string(tmp_value).length();
-                // temp->SetSelection(pos, pos);
-            }
-#endif
+            tmp_value = (int)value;
         }
 	}), temp->GetTextCtrl()->GetId());
 
@@ -1375,6 +1356,10 @@ void SpinCtrl::propagate_value()
             on_kill_focus();
 	} else {
         auto ctrl = dynamic_cast<SpinInput *>(window);
+        tmp_value = std::min(std::max(tmp_value, ctrl->GetMin()), ctrl->GetMax());
+        if (ctrl->GetValue() != tmp_value)
+            ctrl->SetValue(tmp_value); // Clamp now when the user is done typing (kill focus / Enter / spin arrows)
+
         if (m_value.empty()
             ? !ctrl->GetTextCtrl()->GetLabel().IsEmpty()
             : ctrl->GetValue() != boost::any_cast<int>(m_value))
@@ -1419,39 +1404,6 @@ using choice_ctrl = ::ComboBox; // BBS
 
 static std::map<std::string, DynamicList*> dynamic_lists;
 
-static bool is_plugin_printer_agent_key(const std::string& value)
-{
-    return value.rfind("plugin:", 0) == 0;
-}
-
-static int printer_agent_item_for_enum_index(const choice_ctrl* field, int enum_index)
-{
-    if (!field)
-        return -1;
-
-    const unsigned int count = field->GetCount();
-    for (unsigned int idx = 0; idx < count; ++idx) {
-        if (void* data = field->GetClientData(idx)) {
-            const int stored = static_cast<int>(reinterpret_cast<uintptr_t>(data)) - 1;
-            if (stored == enum_index)
-                return static_cast<int>(idx);
-        }
-    }
-
-    return -1;
-}
-
-static int printer_agent_enum_index_for_item(const choice_ctrl* field, int item_index, int fallback)
-{
-    if (!field || item_index < 0)
-        return fallback;
-
-    if (void* data = field->GetClientData(item_index))
-        return static_cast<int>(reinterpret_cast<uintptr_t>(data)) - 1;
-
-    return fallback;
-}
-
 void Choice::register_dynamic_list(std::string const &optname, DynamicList *list) { dynamic_lists.emplace(optname, list); }
 
 void DynamicList::update()
@@ -1534,33 +1486,7 @@ void Choice::BUILD()
 	window = dynamic_cast<wxWindow*>(temp);
 
 	if (! m_opt.enum_labels.empty() || ! m_opt.enum_values.empty()) {
-	    if (m_opt_id == "printer_agent") {
-	        const bool has_builtin_agents = std::any_of(m_opt.enum_values.begin(), m_opt.enum_values.end(),
-	            [](const std::string& value) { return !is_plugin_printer_agent_key(value); });
-	        const bool has_plugin_agents = std::any_of(m_opt.enum_values.begin(), m_opt.enum_values.end(),
-	            [](const std::string& value) { return is_plugin_printer_agent_key(value); });
-
-	        auto append_agent_rows = [this, temp](bool plugins) {
-	            for (size_t i = 0; i < m_opt.enum_values.size(); ++i) {
-	                const bool is_plugin = is_plugin_printer_agent_key(m_opt.enum_values[i]);
-	                if (is_plugin != plugins)
-	                    continue;
-
-	                const wxString label = i < m_opt.enum_labels.size() ? _(m_opt.enum_labels[i]) : wxString(m_opt.enum_values[i]);
-	                const int item = temp->Append(label);
-	                temp->SetClientData(item, reinterpret_cast<void*>(static_cast<uintptr_t>(i + 1)));
-	            }
-	        };
-
-	        if (has_builtin_agents) {
-	            temp->Append(_L("System agents"), wxNullBitmap, DD_ITEM_STYLE_SPLIT_ITEM | DD_ITEM_STYLE_DISABLED);
-	            append_agent_rows(false);
-	        }
-	        if (has_plugin_agents) {
-	            temp->Append(_L("Plugins"), wxNullBitmap, DD_ITEM_STYLE_SPLIT_ITEM | DD_ITEM_STYLE_DISABLED);
-	            append_agent_rows(true);
-	        }
-	    } else if (m_opt.enum_labels.empty()) {
+	    if (m_opt.enum_labels.empty()) {
 			// Append non-localized enum_values
 			for (auto el : m_opt.enum_values)
 				temp->Append(el);
@@ -1667,7 +1593,7 @@ void Choice::set_selection()
 	switch (m_opt.type) {
 	case coEnum:{
         const int val = m_opt.default_value->getInt();
-        field->SetSelection(m_opt_id == "printer_agent" ? printer_agent_item_for_enum_index(field, val) : val);
+        field->SetSelection(val);
 		break;
 	}
 	case coFloat:
@@ -1717,12 +1643,7 @@ void Choice::set_value(const std::string& value, bool change_event)  //! Redunda
 	}
 
 	choice_ctrl* field = dynamic_cast<choice_ctrl*>(window);
-	if (m_opt_id == "printer_agent") {
-		const int enum_index = idx == m_opt.enum_values.size() ?
-			(m_opt.default_value ? m_opt.default_value->getInt() : 0) :
-			static_cast<int>(idx);
-		field->SetSelection(printer_agent_item_for_enum_index(field, enum_index));
-	} else if (idx == m_opt.enum_values.size())
+	if (idx == m_opt.enum_values.size())
 		field->SetValue(value);
 	else
 		field->SetSelection(idx);
@@ -1788,33 +1709,11 @@ void Choice::set_value(const boost::any& value, bool change_event)
 	case coEnum:
     // BBS
 	case coEnums: {
-	    auto printer_agent_index_from_key = [this](const std::string& key) {
-	        auto it = std::find(m_opt.enum_values.begin(), m_opt.enum_values.end(), key);
-	        if (it != m_opt.enum_values.end())
-	            return static_cast<int>(it - m_opt.enum_values.begin());
-	        return m_opt.default_value ? m_opt.default_value->getInt() : 0;
-	    };
-
-	    int val = 0;
-	    if (m_opt_id == "printer_agent") {
-	        if (const int* int_value = boost::any_cast<int>(&value))
-	            val = *int_value;
-	        else if (const wxString* wx_value = boost::any_cast<wxString>(&value))
-	            val = printer_agent_index_from_key(into_u8(*wx_value));
-	        else if (const std::string* string_value = boost::any_cast<std::string>(&value))
-	            val = printer_agent_index_from_key(*string_value);
-	        else {
-	            m_disable_change_event = false;
-	            return;
-	        }
-	    } else
-	        val = boost::any_cast<int>(value);
+	    int val = boost::any_cast<int>(value);
 
 	    int selection = val;
 
-	    if (m_opt_id == "printer_agent") {
-	        selection = printer_agent_item_for_enum_index(field, val);
-	    } else if (m_opt_id == "input_shaping_type") {
+	    if (m_opt_id == "input_shaping_type") {
 	        if (field != nullptr) {
 	            const unsigned int count = field->GetCount();
 	            int match_index = -1;
@@ -1936,12 +1835,6 @@ boost::any& Choice::get_value()
     {
         if (m_opt.nullable && field->GetSelection() == -1)
             m_value = ConfigOptionEnumsGenericNullable::nil_value();
-        else if (m_opt_id == "printer_agent")
-        {
-            const int selection = field->GetSelection();
-            const int fallback = m_opt.default_value ? m_opt.default_value->getInt() : 0;
-            m_value = printer_agent_enum_index_for_item(field, selection, fallback);
-        }
         else if (m_opt_id == "input_shaping_type")
         {
             int selection = field->GetSelection();
@@ -2083,6 +1976,171 @@ void Choice::msw_rescale()
 }
 
 
+// PrinterAgentChoice
+
+void PrinterAgentChoice::reload_rows()
+{
+    auto* combo = dynamic_cast<choice_ctrl*>(window); // wxWidgets ComboBox
+    if (!combo)
+        return;
+
+    // clear ComboBox
+    combo->Clear();
+
+    // helpers
+    const auto agents = NetworkAgentFactory::get_registered_printer_agents();
+    const bool has_builtin_agents = std::any_of(agents.begin(), agents.end(),
+                                                [](const PrinterAgentInfo& a) { return !a.is_plugin(); });
+    const bool has_plugin_agents = std::any_of(agents.begin(), agents.end(),
+                                               [](const PrinterAgentInfo& a) { return a.is_plugin(); });
+
+    auto append_agent_rows = [combo](bool is_plugin)
+    {
+        const auto agents = NetworkAgentFactory::get_registered_printer_agents();
+        for (size_t i = 0; i < agents.size(); ++i)
+        {
+            if (agents[i].is_plugin() != is_plugin)
+                continue;
+            const int item = combo->Append(_(agents[i].display_name));
+            // why: carry the agent-id string on the row. alias is an owned wxString (auto-freed, never rendered)
+            combo->SetItemAlias(item, from_u8(agents[i].id));
+        }
+    };
+
+    // append rows
+    if (has_builtin_agents)
+    {
+        combo->Append(_L("System agents"), wxNullBitmap, DD_ITEM_STYLE_SPLIT_ITEM | DD_ITEM_STYLE_DISABLED);
+        append_agent_rows(false); // append rows for agents that are not plugins
+    }
+    if (has_plugin_agents)
+    {
+        combo->Append(_L("Plugins"), wxNullBitmap, DD_ITEM_STYLE_SPLIT_ITEM | DD_ITEM_STYLE_DISABLED);
+        append_agent_rows(true); // append rows for agents that are plugins
+    }
+}
+
+void PrinterAgentChoice::BUILD()
+{
+    wxSize size(def_width_wider() * m_em_unit, wxDefaultCoord);
+    if (m_opt.height >= 0) size.SetHeight(m_opt.height * m_em_unit);
+    if (m_opt.width >= 0) size.SetWidth(m_opt.width * m_em_unit);
+
+    static Builder<choice_ctrl> builder;
+    choice_ctrl* temp = builder.build(m_parent, wxID_ANY, wxString(""), wxDefaultPosition, size, 0, nullptr,
+                                      wxCB_READONLY);
+    temp->Clear();
+    temp->GetDropDown().SetUseContentWidth(true);
+    if (parent_is_custom_ctrl && m_opt.height < 0)
+        opt_height = (double)temp->GetTextCtrl()->GetSize().GetHeight() / m_em_unit;
+    temp->SetTextLabel(_L(m_opt.sidetext));
+    m_combine_side_text = true;
+#ifdef __WXGTK3__
+    wxSize best_sz = temp->GetBestSize();
+    if (best_sz.x > size.x) temp->SetSize(best_sz);
+#endif
+    if (!wxOSX) temp->SetBackgroundStyle(wxBG_STYLE_PAINT);
+
+    window = dynamic_cast<wxWindow*>(temp);
+
+    reload_rows();
+
+    temp->Bind(wxEVT_COMBOBOX, [this](wxCommandEvent&) { on_change_field(); }, temp->GetId());
+    temp->SetToolTip(get_tooltip_text(temp->GetValue()));
+}
+
+// Resolve CONFIG id string to a matching row in the live REGISTRY. "" uses the vendor default.
+// An unregistered id clears selection and shows "<id> (missing)" as free text.
+void PrinterAgentChoice::set_value(const std::string& value, bool change_event)
+{
+    m_disable_change_event = !change_event;
+
+    auto* field = dynamic_cast<choice_ctrl*>(window);
+
+    // check if any row's corresponding id matches the agent id we are attempting to set
+    const std::string effective_agent_id = wxGetApp().resolve_printer_agent_id(value);
+    const unsigned int count = field->GetCount();
+    int match = wxNOT_FOUND;
+    for (unsigned int i = 0; i < count; ++i)
+    {
+        if (into_u8(field->GetItemAlias(i)) == effective_agent_id) // if alias == id
+        {
+            match = static_cast<int>(i);
+            break;
+        }
+    }
+
+    // based on match or not, set selection and value
+    // - SetSelection and SetValue are UI to manipulate the display of the ComboBox
+    // - SetSelection automatically calls SetValue for the same value
+    // - we can also SetValue separately from SetSelection
+    if (match == wxNOT_FOUND)
+    {
+        field->SetSelection(wxNOT_FOUND); // nothing shows as selected in the dropdown
+        field->SetValue(from_u8(value + " (missing)")); // set a value not in the selection (upper display field)
+    }
+    else
+    {
+        // display name of agent shows both in upper display field and appears selected in dropdown
+        field->SetSelection(match);
+    }
+
+    m_disable_change_event = false;
+}
+
+// Accept boost::any values from callers (usually to OptionsGroup/Field parent classes) and normalize them to an agent id.
+// Then use PrinterAgentChoice::set_value(std::string& value, ...)
+void PrinterAgentChoice::set_value(const boost::any& value, bool change_event)
+{
+    m_disable_change_event = !change_event;
+
+    auto* field = dynamic_cast<choice_ctrl*>(window);
+    if (value.empty())
+    {
+        field->SetValue("");
+        m_value = value;
+        m_disable_change_event = false;
+        return;
+    }
+
+    std::string id;
+    if (const std::string* s = boost::any_cast<std::string>(&value))
+        id = *s;
+    else if (const wxString* w = boost::any_cast<wxString>(&value))
+        id = into_u8(*w);
+    set_value(id, change_event);
+}
+
+// A real row returns its alias, which is the agent id. Header rows, missing rows,
+// and no selection return empty boost::any so the custom writer leaves config unchanged.
+boost::any& PrinterAgentChoice::get_value()
+{
+    auto* field = dynamic_cast<choice_ctrl*>(window);
+    const int sel = field->GetSelection();
+    const std::string id = sel < 0 ? std::string{} : into_u8(field->GetItemAlias(sel));
+    if (id.empty())
+        m_value = boost::any{};
+    else
+        m_value = id;
+    return m_value;
+}
+
+void PrinterAgentChoice::enable() { dynamic_cast<choice_ctrl*>(window)->Enable(); }
+void PrinterAgentChoice::disable() { dynamic_cast<choice_ctrl*>(window)->Disable(); }
+
+void PrinterAgentChoice::msw_rescale()
+{
+    Field::msw_rescale();
+
+    auto* field = dynamic_cast<choice_ctrl*>(window)->GetTextCtrl();
+    wxSize size(wxDefaultSize);
+    size.SetWidth((m_opt.width > 0 ? m_opt.width : def_width_wider()) * m_em_unit);
+    field->SetMinSize(wxSize(-1, int(1.5f * field->GetFont().GetPixelSize().y + 0.5f)));
+    field->SetSize(size);
+
+    dynamic_cast<choice_ctrl*>(window)->Rescale();
+}
+
 void PluginField::BUILD()
 {
     auto* panel = new wxPanel(m_parent, wxID_ANY);

src/slic3r/GUI/Field.hpp

@@ -469,6 +469,44 @@ public:
     void            suppress_scroll();
 };
 
+// printer_agent is a coString whose choices come from the live agent registry.
+// PrinterAgentChoice uses a ComboBox directly because Choice expects static config enums.
+// Real rows carry the stored agent id in the row alias (SetItemAlias/GetItemAlias).
+class PrinterAgentChoice : public Field
+{
+	using Field::Field;
+
+public:
+	PrinterAgentChoice(const ConfigOptionDef& opt, const t_config_option_key& id) : Field(opt, id)
+	{
+	}
+
+	PrinterAgentChoice(wxWindow* parent, const ConfigOptionDef& opt, const t_config_option_key& id) : Field(
+		parent, opt, id)
+	{
+	}
+
+	~PrinterAgentChoice()
+	{
+	}
+
+	wxWindow* window{nullptr};
+
+	void BUILD() override;
+	// Clear and repopulate rows from the live registry (grouped System agents / Plugins).
+	// Does not change selection; the caller follows with set_value(stored id).
+	void reload_rows();
+
+	void set_value(const std::string& value, bool change_event = false);
+	void set_value(const boost::any& value, bool change_event = false) override;
+	boost::any& get_value() override;
+
+	void enable() override;
+	void disable() override;
+	void msw_rescale() override;
+	wxWindow* getWindow() override { return window; }
+};
+
 class PluginField : public Field {
     using Field::Field;
 public:

src/slic3r/GUI/FilamentPickerDialog.cpp

@@ -105,9 +105,8 @@ FilamentPickerDialog::FilamentPickerDialog(wxWindow *parent, const wxString& fil
     container_sizer->Add(main_sizer, 1, wxEXPAND | wxALL, FromDIP(10));
     container_sizer->Add(dlg_btns, 0, wxEXPAND);
 
-    SetSizer(container_sizer);
+    SetSizerAndFit(container_sizer);
     Layout();
-    container_sizer->Fit(this);
 
     // Position the dialog relative to the parent window
     if (GetParent()) {

src/slic3r/GUI/GCodeViewer.cpp

@@ -1134,8 +1134,9 @@ void GCodeViewer::load_as_gcode(const GCodeProcessorResult& gcode_result, const
     if (current_top_layer_only != required_top_layer_only)
         m_viewer.toggle_top_layer_only_view_range();
 
-    // ORCA: darken layers below the current one while scrubbing the preview (ported from preFlight)
+    // ORCA: darken the layers the preview layer slider is not scrubbed to
     m_viewer.set_dim_previous_layers(get_app_config()->get_bool("preview_dim_previous_layers"));
+    m_viewer.set_dim_previous_layers_brightness(0.01f * std::stoi(get_app_config()->get("preview_dim_previous_layers_brightness")));
 
     // avoid processing if called with the same gcode_result
     if (m_last_result_id == gcode_result.id && wxGetApp().is_editor()) {

src/slic3r/GUI/GCodeViewer.hpp

@@ -333,9 +333,12 @@ public:
 
     libvgcode::EViewType get_view_type() const { return m_viewer.get_view_type(); }
 
-    // ORCA: darken layers below the current top layer while scrubbing the preview (ported from preFlight)
+    // ORCA: darken the layers not scrubbed to while using the preview layer slider
     void set_dim_previous_layers(bool value) { m_viewer.set_dim_previous_layers(value); }
     bool is_dim_previous_layers() const { return m_viewer.is_dim_previous_layers(); }
+    // ORCA: brightness of those darkened layers, 1.0 = unchanged, 0.0 = black
+    void set_dim_previous_layers_brightness(float value) { m_viewer.set_dim_previous_layers_brightness(value); }
+    float get_dim_previous_layers_brightness() const { return m_viewer.get_dim_previous_layers_brightness(); }
 
     void set_layers_z_range(const std::array<unsigned int, 2>& layers_z_range);
 

src/slic3r/GUI/GLCanvas3D.cpp

@@ -1853,6 +1853,8 @@ void GLCanvas3D::enable_collapse_toolbar(bool enable)
 void GLCanvas3D::enable_plate_chrome(bool enable)
 {
     m_plate_chrome_enabled = enable;
+bool GLCanvas3D::has_mouse_capture() const {
+    return m_canvas != nullptr && m_canvas->HasCapture();
 }
 
 void GLCanvas3D::zoom_to_bed()
@@ -2204,7 +2206,7 @@ void GLCanvas3D::render(bool only_init)
 
 	// Negative coordinate means out of the window, likely because the window was deactivated.
 	// In that case the tooltip should be hidden.
-    if (m_mouse.position.x() >= 0. && m_mouse.position.y() >= 0.) {
+    if (m_mouse.position.x() >= 0. && m_mouse.position.y() >= 0. || has_mouse_capture()) { // ORCA continue to capture mouse pos mid drag
         if (tooltip.empty())
             tooltip = m_layers_editing.get_tooltip(*this);
 
@@ -2889,6 +2891,9 @@ void GLCanvas3D::reload_scene(bool refresh_immediately, bool force_full_scene_re
         }
 
         if (wt && (need_wipe_tower || filaments_count > 1) && !wxGetApp().plater()->only_gcode_mode() && !wxGetApp().plater()->is_gcode_3mf()) {
+            // The tower size estimate reads printer- and filament-scope keys, which the print preset
+            // does not carry; built once here rather than per plate.
+            const DynamicPrintConfig full_config = wxGetApp().preset_bundle->full_config();
             for (int plate_id = 0; plate_id < n_plates; plate_id++) {
                 // If print ByObject and there is only one object in the plate, the wipe tower is allowed to be generated.
                 PartPlate* part_plate = ppl.get_plate(plate_id);
@@ -2913,51 +2918,26 @@ void GLCanvas3D::reload_scene(bool refresh_immediately, bool force_full_scene_re
                 if (part_plate->get_objects_on_this_plate().empty()) continue;
 
                 float brim_width = print->wipe_tower_data(filaments_count).brim_width;
-                const DynamicPrintConfig &print_cfg   = wxGetApp().preset_bundle->prints.get_edited_preset().config;
                 int nozzle_nums = wxGetApp().preset_bundle->get_printer_extruder_count();
-                Vec3d wipe_tower_size = ppl.get_plate(plate_id)->estimate_wipe_tower_size(print_cfg, w, v, nozzle_nums, 0, false, dynamic_cast<const ConfigOptionBool*>(dconfig.option("enable_wrapping_detection"))->value);
+                Vec3d wipe_tower_size = ppl.get_plate(plate_id)->estimate_wipe_tower_size(full_config, w, v, nozzle_nums, 0, false, dynamic_cast<const ConfigOptionBool*>(dconfig.option("enable_wrapping_detection"))->value);
 
-                {
-                    const float                 margin     = WIPE_TOWER_MARGIN + brim_width;
-                    BoundingBoxf3               plate_bbox = part_plate->get_bounding_box();
-                    BoundingBoxf                plate_bbox_2d(Vec2d(plate_bbox.min(0), plate_bbox.min(1)), Vec2d(plate_bbox.max(0), plate_bbox.max(1)));
-                    const std::vector<Pointfs> &extruder_areas = part_plate->get_extruder_areas();
-                    for (Pointfs points : extruder_areas) {
-                        BoundingBoxf bboxf(points);
-                        plate_bbox_2d.min = plate_bbox_2d.min(0) >= bboxf.min(0) ? plate_bbox_2d.min : bboxf.min;
-                        plate_bbox_2d.max = plate_bbox_2d.max(0) <= bboxf.max(0) ? plate_bbox_2d.max : bboxf.max;
-                    }
-
-                    coordf_t plate_bbox_x_min_local_coord = plate_bbox_2d.min(0) - plate_origin(0);
-                    coordf_t plate_bbox_x_max_local_coord = plate_bbox_2d.max(0) - plate_origin(0);
-                    coordf_t plate_bbox_y_max_local_coord = plate_bbox_2d.max(1) - plate_origin(1);
-
-                    if (!current_print->is_step_done(psWipeTower) || !current_print->wipe_tower_data().wipe_tower_mesh_data) {
-                        // update for wipe tower position
-                        {
-                            int volume_idx_wipe_tower_new = m_volumes.load_wipe_tower_preview(1000 + plate_id, x + plate_origin(0), y + plate_origin(1),
-                                                                                              (float) wipe_tower_size(0), (float) wipe_tower_size(1), (float) wipe_tower_size(2),
-                                                                                              a,
-                                                                                              /*!print->is_step_done(psWipeTower)*/ true, brim_width);
-                            int volume_idx_wipe_tower_old = volume_idxs_wipe_tower_old[plate_id];
-                            if (volume_idx_wipe_tower_old != -1) map_glvolume_old_to_new[volume_idx_wipe_tower_old] = volume_idx_wipe_tower_new;
-                        }
-                    } else {
-                        const float margin                    = 2.f;
-                        auto        tower_bottom = current_print->wipe_tower_data().wipe_tower_mesh_data->bottom;
-                        tower_bottom.translate(scaled(Vec2d{x, y}));
-                        tower_bottom.translate(scaled(Vec2d{plate_origin[0], plate_origin[1]}));
-                        auto tower_bottom_bbox = get_extents(tower_bottom);
-                        BoundingBoxf3 plate_bbox        = wxGetApp().plater()->get_partplate_list().get_plate(plate_id)->get_build_volume(true);
-                        BoundingBox   plate_bbox2d      = BoundingBox(scaled(Vec2f(plate_bbox.min[0], plate_bbox.min[1])), scaled(Vec2f(plate_bbox.max[0], plate_bbox.max[1])));
-                        Vec2f         offset            = WipeTower::move_box_inside_box(tower_bottom_bbox, plate_bbox2d, scaled(margin));
-                        int volume_idx_wipe_tower_new = m_volumes.load_real_wipe_tower_preview(1000 + plate_id, x + plate_origin(0), y + plate_origin(1),
-                                                                                               current_print->wipe_tower_data().wipe_tower_mesh_data->real_wipe_tower_mesh,
-                                                                                               current_print->wipe_tower_data().wipe_tower_mesh_data->real_brim_mesh,
-                                                                                            true,a,/*!print->is_step_done(psWipeTower)*/ true, m_initialized);
-                        int volume_idx_wipe_tower_old = volume_idxs_wipe_tower_old[plate_id];
-                        if (volume_idx_wipe_tower_old != -1) map_glvolume_old_to_new[volume_idx_wipe_tower_old] = volume_idx_wipe_tower_new;
-                    }
+                // The stored position is already clamped onto the bed, by
+                // set_default_wipe_tower_pos_for_plate and again on every drag.
+                if (!current_print->is_step_done(psWipeTower) || !current_print->wipe_tower_data().wipe_tower_mesh_data) {
+                    // update for wipe tower position
+                    int volume_idx_wipe_tower_new = m_volumes.load_wipe_tower_preview(1000 + plate_id, x + plate_origin(0), y + plate_origin(1),
+                                                                                      (float) wipe_tower_size(0), (float) wipe_tower_size(1), (float) wipe_tower_size(2),
+                                                                                      a,
+                                                                                      /*!print->is_step_done(psWipeTower)*/ true, brim_width);
+                    int volume_idx_wipe_tower_old = volume_idxs_wipe_tower_old[plate_id];
+                    if (volume_idx_wipe_tower_old != -1) map_glvolume_old_to_new[volume_idx_wipe_tower_old] = volume_idx_wipe_tower_new;
+                } else {
+                    int volume_idx_wipe_tower_new = m_volumes.load_real_wipe_tower_preview(1000 + plate_id, x + plate_origin(0), y + plate_origin(1),
+                                                                                           current_print->wipe_tower_data().wipe_tower_mesh_data->real_wipe_tower_mesh,
+                                                                                           current_print->wipe_tower_data().wipe_tower_mesh_data->real_brim_mesh,
+                                                                                        true,a,/*!print->is_step_done(psWipeTower)*/ true, m_initialized);
+                    int volume_idx_wipe_tower_old = volume_idxs_wipe_tower_old[plate_id];
+                    if (volume_idx_wipe_tower_old != -1) map_glvolume_old_to_new[volume_idx_wipe_tower_old] = volume_idx_wipe_tower_new;
                 }
             }
         }
@@ -4267,6 +4247,23 @@ void GLCanvas3D::on_mouse(wxMouseEvent& evt)
     // BBS: single snapshot
     Plater::SingleSnapshot single(wxGetApp().plater());
 
+#ifdef __WXMAC__
+    // On macOS, the mouse key state is only present for mouse btn related events such as wxEVT_LEFT_DOWN.
+    // For other events, all buttons are reported as non-pressed, such as window leaving event. This causes
+    // imgui stopped responding if cursor moved out of window, such as
+    // https://github.com/OrcaSlicer/OrcaSlicer/pull/14999#issuecomment-5151344759
+    // We solve this by correcting the state of the event from the actual mouse state querying with `wxGetMouseState()`
+    // so it works like on other platforms.
+    {
+        const auto state = wxGetMouseState();
+        evt.SetLeftDown(state.LeftIsDown());
+        evt.SetMiddleDown(state.MiddleIsDown());
+        evt.SetRightDown(state.RightIsDown());
+        evt.SetAux1Down(state.Aux1IsDown());
+        evt.SetAux2Down(state.Aux2IsDown());
+    }
+#endif
+
 #if ENABLE_RETINA_GL
     const float scale = m_retina_helper->get_scale_factor();
     evt.SetX(evt.GetX() * scale);
@@ -4280,11 +4277,27 @@ void GLCanvas3D::on_mouse(wxMouseEvent& evt)
         // ignore left up events coming from imgui windows and not processed by them
         m_mouse.ignore_left_up = true;
     m_tooltip.set_in_imgui(false);
-    if (imgui->update_mouse_data(evt)) {
+
+    // while a non-ImGui drag is already in progress (gizmo grabber, object move, rectangle selection, layer editing),
+    // don't let ImGui/ImGuizmo claim the event just because the cursor is hovering something like the navigator cube
+    // that incorrectly suppresses the active drag's tooltip and can interrupt its processing. The active drag always takes priority.
+    const bool other_drag_active = m_gizmos.is_dragging() || m_mouse.dragging || m_rectangle_selection.is_dragging() || m_layers_editing.state == LayersEditing::Editing;
+
+    if (imgui->update_mouse_data(evt) && !other_drag_active) {
         if ((evt.LeftDown() || (evt.Moving() && (evt.AltDown() || evt.ShiftDown()))) && m_canvas != nullptr)
             m_canvas->SetFocus();
         m_mouse.position = evt.Leaving() ? Vec2d(-1.0, -1.0) : pos.cast<double>();
         m_tooltip.set_in_imgui(true);
+
+        // ORCA keep tracking mouse position while drag active and cursor not in window bounds
+        const bool imgui_dragging_active = (GImGui != nullptr && ImGui::GetIO().MouseDown[0] && GImGui->ActiveId != 0) || m_navigator_dragging;
+        if (!has_mouse_capture() && imgui_dragging_active)
+            m_canvas->CaptureMouse();
+
+        // release capture as soon as the button goes up
+        if (evt.LeftUp() || evt.MiddleUp() || evt.RightUp())
+            mouse_up_cleanup();
+
         render();
 #ifdef SLIC3R_DEBUG_MOUSE_EVENTS
         printf((format_mouse_event_debug_message(evt) + " - Consumed by ImGUI\n").c_str());
@@ -4398,6 +4411,10 @@ void GLCanvas3D::on_mouse(wxMouseEvent& evt)
             m_main_toolbar.on_mouse(evt2, *this);
         }
 
+        // ORCA keep tracking mouse position while drag active and cursor not in window bounds
+        if (!has_mouse_capture() && evt.LeftIsDown() && m_gizmos.is_dragging())
+            m_canvas->CaptureMouse();
+
         if (evt.LeftUp() || evt.MiddleUp() || evt.RightUp())
             mouse_up_cleanup();
 
@@ -4503,6 +4520,9 @@ void GLCanvas3D::on_mouse(wxMouseEvent& evt)
             // Start editing the layer height.
             m_layers_editing.state = LayersEditing::Editing;
             _perform_layer_editing_action(&evt);
+
+            if (!has_mouse_capture()) // ORCA keep tracking mouse position while drag active and cursor not in window bounds
+                m_canvas->CaptureMouse();
         }
 
         else {
@@ -4516,6 +4536,10 @@ void GLCanvas3D::on_mouse(wxMouseEvent& evt)
                     && m_gizmos.get_current_type() != GLGizmosManager::MmSegmentation
                     && m_gizmos.get_current_type() != GLGizmosManager::FuzzySkin) {
                     m_rectangle_selection.start_dragging(m_mouse.position, evt.ShiftDown() ? GLSelectionRectangle::Select : GLSelectionRectangle::Deselect);
+
+                    if (!has_mouse_capture())  // ORCA keep tracking mouse position while drag active and cursor not in window bounds
+                        m_canvas->CaptureMouse();
+
                     m_dirty = true;
                 }
             }
@@ -4583,6 +4607,9 @@ void GLCanvas3D::on_mouse(wxMouseEvent& evt)
                             m_mouse.drag.start_position_3D = m_mouse.scene_position;
                             m_sequential_print_clearance_first_displacement = true;
                             m_moving = true;
+
+                            if (!has_mouse_capture()) // ORCA keep tracking mouse position while drag active and cursor not in window bounds
+                                m_canvas->CaptureMouse();
                         }
                     }
                 }
@@ -4591,6 +4618,10 @@ void GLCanvas3D::on_mouse(wxMouseEvent& evt)
     }
     else if (evt.Dragging() && evt.LeftIsDown() && m_mouse.drag.move_volume_idx != -1 && m_layers_editing.state == LayersEditing::Unknown) {
         if (m_canvas_type != ECanvasType::CanvasAssembleView) {
+
+            if (!has_mouse_capture()) // ORCA keep tracking mouse position while drag active and cursor not in window bounds
+                m_canvas->CaptureMouse();
+
             if (!m_mouse.drag.move_requires_threshold) {
                 m_mouse.dragging = true;
                 Vec3d cur_pos = m_mouse.drag.start_position_3D;
@@ -4642,6 +4673,10 @@ void GLCanvas3D::on_mouse(wxMouseEvent& evt)
     else if (evt.Dragging() && evt.LeftIsDown() && m_picking_enabled && m_rectangle_selection.is_dragging()) {
         //BBS not in assemble view
         if (m_canvas_type != ECanvasType::CanvasAssembleView) {
+
+            if (!has_mouse_capture()) // ORCA keep tracking mouse position while drag active and cursor not in window bounds
+                m_canvas->CaptureMouse();
+
             m_rectangle_selection.dragging(pos.cast<double>());
             m_dirty = true;
         }
@@ -4651,12 +4686,19 @@ void GLCanvas3D::on_mouse(wxMouseEvent& evt)
 
         if (m_layers_editing.state != LayersEditing::Unknown && layer_editing_object_idx != -1) {
             if (m_layers_editing.state == LayersEditing::Editing) {
+                if (!has_mouse_capture()) // ORCA keep tracking mouse position while drag active and cursor not in window bounds
+                    m_canvas->CaptureMouse();
+
                 _perform_layer_editing_action(&evt);
                 m_mouse.position = pos.cast<double>();
             }
         }
         // do not process the dragging if the left mouse was set down in another canvas
         else if (is_camera_rotate(evt, button_mappings)) {
+
+            if (!has_mouse_capture()) // ORCA keep tracking mouse position while drag active and cursor not in window bounds
+                m_canvas->CaptureMouse();
+
             // Orca: Sphere rotation for painting view
             // if dragging over blank area with left button or other button mapped to rotate, then rotate
             bool middle_or_right_button_used_as_rotate = (evt.MiddleIsDown() && button_mappings[MouseButton::Middle] == MouseAction::Rotation) ||
@@ -4736,6 +4778,10 @@ void GLCanvas3D::on_mouse(wxMouseEvent& evt)
             m_mouse.drag.start_position_3D = Vec3d((double)pos(0), (double)pos(1), 0.0);
         }
         else if (is_camera_pan(evt, button_mappings)) {
+
+            if (!has_mouse_capture()) // ORCA keep tracking mouse position while drag active and cursor not in window bounds
+                m_canvas->CaptureMouse();
+
             // if dragging with right button or if button functions swapped and dragging with left button over blank area then pan
             if (m_mouse.is_start_position_2D_defined()) {
                 // get point in model space at Z = 0
@@ -4800,7 +4846,9 @@ void GLCanvas3D::on_mouse(wxMouseEvent& evt)
                 deselect_all();
         }
         //BBS Select plate in this 3D canvas.
-        else if (evt.LeftUp() && !m_mouse.dragging && m_picking_enabled && !m_hover_plate_idxs.empty() && (m_canvas_type == CanvasView3D) && !is_layers_editing_enabled())
+        // The left up may come from an ImGui window (e.g. a drag started on the gizmo floating window and released over the bed),
+        // in which case it must not be treated as a click on the plate, otherwise the gizmo would be closed (see deselect_all below).
+        else if (evt.LeftUp() && !m_mouse.ignore_left_up && !m_mouse.dragging && m_picking_enabled && !m_hover_plate_idxs.empty() && (m_canvas_type == CanvasView3D) && !is_layers_editing_enabled())
         {
                 int hover_idx = m_hover_plate_idxs.front();
                 wxGetApp().plater()->select_plate_by_hover_id(hover_idx);
@@ -6151,9 +6199,18 @@ void GLCanvas3D::_render_3d_navigator()
 {
     if (!wxGetApp().show_3d_navigator()) {
         m_canvas_toolbar_pos[0] = 0;
+        m_navigator_dragging = false;
         return;
     }
 
+    // Fix stealing capture event from other drag events
+    const bool other_drag_active = !m_navigator_dragging && (m_moving || m_rectangle_selection.is_dragging() || m_gizmos.is_dragging() || m_layers_editing.state == LayersEditing::Editing);
+
+    ImGuiIO& io = ImGui::GetIO();
+    const bool saved_mouse_down0 = io.MouseDown[0];
+    if (other_drag_active)
+        io.MouseDown[0] = false;
+
     ImGuizmo::BeginFrame();
 
     auto& style                                = ImGuizmo::GetStyle();
@@ -6165,10 +6222,10 @@ void GLCanvas3D::_render_3d_navigator()
     strcpy(style.AxisLabels[ImGuizmo::Axis::Axis_X], "Y"); // ORCA use uppercase to match text on tranform widgets
     strcpy(style.AxisLabels[ImGuizmo::Axis::Axis_Y], "Z"); // ORCA use uppercase to match text on tranform widgets
     strcpy(style.AxisLabels[ImGuizmo::Axis::Axis_Z], "X"); // ORCA use uppercase to match text on tranform widgets
-    strcpy(style.FaceLabels[ImGuizmo::FACES::FACE_FRONT], _utf8("Front").c_str());
+    strcpy(style.FaceLabels[ImGuizmo::FACES::FACE_FRONT], _u8L_CONTEXT("Front", "Camera View").c_str());
     strcpy(style.FaceLabels[ImGuizmo::FACES::FACE_BACK], _u8L_CONTEXT("Back", "Camera View").c_str());
-    strcpy(style.FaceLabels[ImGuizmo::FACES::FACE_TOP], _utf8("Top").c_str());
-    strcpy(style.FaceLabels[ImGuizmo::FACES::FACE_BOTTOM], _utf8("Bottom").c_str());
+    strcpy(style.FaceLabels[ImGuizmo::FACES::FACE_TOP], _u8L_CONTEXT("Top", "Camera View").c_str());
+    strcpy(style.FaceLabels[ImGuizmo::FACES::FACE_BOTTOM], _u8L_CONTEXT("Bottom", "Camera View").c_str());
     strcpy(style.FaceLabels[ImGuizmo::FACES::FACE_LEFT], _u8L_CONTEXT("Left", "Camera View").c_str());
     strcpy(style.FaceLabels[ImGuizmo::FACES::FACE_RIGHT], _u8L_CONTEXT("Right", "Camera View").c_str());
 
@@ -6178,7 +6235,6 @@ void GLCanvas3D::_render_3d_navigator()
     sc *= (float) dpi / (float) DPI_DEFAULT;
 #endif // WIN32
 
-    const ImGuiIO& io              = ImGui::GetIO();
     const float viewManipulateLeft = 0;
     const float viewManipulateTop  = io.DisplaySize.y;
     const float camDistance        = 8.f;
@@ -6202,6 +6258,10 @@ void GLCanvas3D::_render_3d_navigator()
                                                  camDistance, ImVec2(viewManipulateLeft, viewManipulateTop - size), ImVec2(size, size),
                                                  0x00101010);
 
+    // Restore the real mouse-down state
+    if (other_drag_active)
+        io.MouseDown[0] = saved_mouse_down0;
+
     if (result.changed) {
         for (unsigned int c = 0; c < 4; ++c) {
             for (unsigned int r = 0; r < 4; ++r) {
@@ -6233,6 +6293,8 @@ void GLCanvas3D::_render_3d_navigator()
 
         request_extra_frame();
     }
+
+    m_navigator_dragging = result.dragging;
 }
 
 #define ENABLE_THUMBNAIL_GENERATOR_DEBUG_OUTPUT 0
@@ -7031,7 +7093,7 @@ void GLCanvas3D::_update_select_plate_toolbar_stats_item(bool force_selected) {
     else
         m_sel_plate_toolbar.show_stats_item = false;
 
-    if (force_selected && m_sel_plate_toolbar.show_stats_item)
+    if (force_selected && m_sel_plate_toolbar.show_stats_item && m_sel_plate_toolbar.m_all_plates_stats_item)
         m_sel_plate_toolbar.m_all_plates_stats_item->selected = true;
 }
 
@@ -9358,8 +9420,12 @@ void GLCanvas3D::_render_imgui_select_plate_toolbar()
 
     //ORCA ImGui::IsWindowHovered() returns false when left_down events on buttons that causes scrollbar disappears for a short time
     auto win_pos = ImGui::GetWindowPos();
-    bool is_win_hovered = ImGui::IsMouseHoveringRect(win_pos, win_pos + ImVec2(window_width + (show_scroll ? scrollbar_size : 0), window_height), !show_scroll); // use non clipped rectangle to reserve clickable area for scrollbar track
-    m_sel_plate_toolbar.is_display_scrollbar = is_win_hovered;
+    bool is_win_hovered = ImGui::IsMouseHoveringRect(win_pos, win_pos + ImVec2(window_width + (show_scroll ? scrollbar_size : 0), window_height), !show_scroll);
+
+    // Also show scrollbar visible and continue to capture mouse position
+    const bool is_scrollbar_active_drag = GImGui != nullptr && ImGui::GetIO().MouseDown[0] && GImGui->ActiveId != 0 && GImGui->ActiveIdWindow == ImGui::GetCurrentWindow();
+
+    m_sel_plate_toolbar.is_display_scrollbar = is_win_hovered || is_scrollbar_active_drag;
 
     imgui.end();
 }

src/slic3r/GUI/GLCanvas3D.hpp

@@ -607,6 +607,7 @@ private:
     bool m_toolpath_outside{ false };
     ECursorType m_cursor_type;
     GLSelectionRectangle m_rectangle_selection;
+    bool m_navigator_dragging{ false };
 
     //BBS:add plate related logic
     mutable std::vector<int> m_hover_volume_idxs;
@@ -943,6 +944,7 @@ public:
     void update_volumes_colors_by_extruder();
 
     bool is_dragging() const { return m_gizmos.is_dragging() || m_moving; }
+    bool has_mouse_capture() const;
 
     void render(bool only_init = false);
     bool is_rendering_enabled()
@@ -1145,6 +1147,10 @@ public:
 
     void set_mouse_as_dragging() { m_mouse.dragging = true; }
     bool is_mouse_dragging() const { return m_mouse.dragging; }
+    // True when the current left up event comes from an ImGui window and was not processed by it
+    // (e.g. a drag that started on a gizmo floating window and was released over the 3D scene).
+    // Such a release is the end of an ImGui interaction, not a click on the scene.
+    bool is_mouse_left_up_ignored() const { return m_mouse.ignore_left_up; }
 
     double get_size_proportional_to_max_bed_size(double factor) const;
 

src/slic3r/GUI/GUI.cpp

@@ -256,18 +256,18 @@ void change_opt_value(DynamicPrintConfig& config, const t_config_option_key& opt
 	}
 }
 
-void show_error(wxWindow* parent, const wxString& message, bool monospaced_font)
+void show_error(wxWindow* parent, const wxString& message, bool has_code_excerpts)
 {
     wxGetApp().CallAfter([=] {
-        ErrorDialog msg(parent, message, monospaced_font);
+        ErrorDialog msg(parent, message, has_code_excerpts);
         msg.ShowModal();
     });
 }
 
-void show_error(wxWindow* parent, const char* message, bool monospaced_font)
+void show_error(wxWindow* parent, const char* message, bool has_code_excerpts)
 {
 	assert(message);
-	show_error(parent, wxString::FromUTF8(message), monospaced_font);
+	show_error(parent, wxString::FromUTF8(message), has_code_excerpts);
 }
 
 void show_error_id(int id, const std::string& message)

src/slic3r/GUI/GUI.hpp

@@ -40,11 +40,11 @@ extern void add_menus(wxMenuBar *menu, int event_preferences_changed, int event_
 // Change option value in config
 void change_opt_value(DynamicPrintConfig& config, const t_config_option_key& opt_key, const boost::any& value, int opt_index = 0);
 
-// If monospaced_font is true, the error message is displayed using html <code><pre></pre></code> tags,
-// so that the code formatting will be preserved. This is useful for reporting errors from the placeholder parser.
-void show_error(wxWindow* parent, const wxString& message, bool monospaced_font = false);
-void show_error(wxWindow* parent, const char* message, bool monospaced_font = false);
-inline void show_error(wxWindow* parent, const std::string& message, bool monospaced_font = false) { show_error(parent, message.c_str(), monospaced_font); }
+// If has_code_excerpts is true, code excerpts (a source line and the caret line below it) render
+// monospaced so the caret aligns. Used for placeholder-parser errors.
+void show_error(wxWindow* parent, const wxString& message, bool has_code_excerpts = false);
+void show_error(wxWindow* parent, const char* message, bool has_code_excerpts = false);
+inline void show_error(wxWindow* parent, const std::string& message, bool has_code_excerpts = false) { show_error(parent, message.c_str(), has_code_excerpts); }
 void show_error_id(int id, const std::string& message);   // For Perl
 void show_info(wxWindow* parent, const wxString& message, const wxString& title = wxString());
 void show_info(wxWindow* parent, const char* message, const char* title = nullptr);

src/slic3r/GUI/GUI_App.cpp

@@ -96,6 +96,7 @@
 #include "../Utils/PresetUpdater.hpp"
 #include "../Utils/PrintHost.hpp"
 #include "../Utils/Process.hpp"
+#include "../Utils/wxInspectorPlugins/Registration.hpp"
 #include "../Utils/MacDarkMode.hpp"
 #include "../Utils/Http.hpp"
 #include "../Utils/InstanceID.hpp"
@@ -306,6 +307,20 @@ public:
 #endif // !__APPLE__
         )
     {
+		// Some desktop environments ignore splash screen typed window properties
+		// when running the app through Wayland,resulting in the titlebar being shown 
+		// on the splash screen. The code below creates a client-side window decoration
+		// when running on Wayland and then removes that decoration. This ensures every 
+		// environment correctly targets and removes the titlebar for this screen.
+		#if defined(__WXGTK__)
+	        if (Slic3r::GUI::is_running_on_wayland()) {
+	            GtkWidget *empty = gtk_fixed_new();
+	            gtk_widget_set_size_request(empty, 0, 0);
+	            gtk_window_set_titlebar(GTK_WINDOW(GetHandle()), empty);
+	            gtk_window_set_decorated(GTK_WINDOW(GetHandle()), false);
+	        }
+		#endif
+		
         this->SetPosition(pos);
         this->CenterOnScreen();
 
@@ -2151,7 +2166,6 @@ void GUI_App::init_networking_callbacks()
                     obj->is_tunnel_mqtt = tunnel;
                     obj->command_request_push_all(true);
                     obj->command_get_version();
-                    obj->erase_user_access_code();
                     obj->command_get_access_code();
                     if (m_agent)
                         m_agent->install_device_cert(obj->get_dev_id(), obj->is_lan_mode_printer());
@@ -2201,7 +2215,6 @@ void GUI_App::init_networking_callbacks()
                                 wxString text;
                                 if (msg == "5") {
                                     obj->set_access_code("");
-                                    obj->erase_user_access_code();
                                     text = wxString::Format(_L("Incorrect password"));
                                     wxGetApp().show_dialog(text);
                                 } else {
@@ -2794,16 +2807,58 @@ void GUI_App::init_plugin_gui_wiring()
         });
     };
 
+    // why: a newly loaded plugin only adds a selectable agent
+    // refresh the dropdown and leave the live agent alone
+    auto refresh_printer_agent_dropdown_after_load = [](const std::string&)
+    {
+        if (!wxTheApp)
+            return;
+
+        GUI_App* app = &GUI::wxGetApp();
+        if (app->is_closing())
+            return;
+
+        app->CallAfter([app]
+        {
+            if (!app->is_closing())
+                app->refresh_printer_agent_dropdown();
+        });
+    };
+
+    // why: the unloaded plugin may have been the provider of the live agent
+    // re-run selection, where a now-missing agent will be cleared
+    // refresh dropdown after
+    auto switch_printer_agent_after_unload = [](const std::string&)
+    {
+        if (!wxTheApp)
+            return;
+
+        GUI_App* app = &GUI::wxGetApp();
+        if (app->is_closing())
+            return;
+
+        app->CallAfter([app] {
+            if (app->is_closing())
+                return;
+
+            app->switch_printer_agent();
+            app->refresh_printer_agent_dropdown();
+        });
+    };
+
     plugin_mgr.subscribe_on_unload_callback(PluginHostUi::close_windows_for_plugin);
     plugin_mgr.subscribe_on_load_callback([refresh_plugins_dialog](const std::string&) { refresh_plugins_dialog(); });
     plugin_mgr.subscribe_on_unload_callback([refresh_plugins_dialog](const std::string&) { refresh_plugins_dialog(); });
     plugin_mgr.subscribe_on_load_callback(NetworkAgentFactory::register_python_plugin);
     plugin_mgr.subscribe_on_unload_callback(NetworkAgentFactory::deregister_python_plugin);
+    plugin_mgr.subscribe_on_load_callback(refresh_printer_agent_dropdown_after_load);
+    plugin_mgr.subscribe_on_unload_callback(switch_printer_agent_after_unload);
     plugin_mgr.subscribe_on_capability_load_callback(
-        [refresh_plugins_dialog](const PluginCapabilityId& capability) {
+        [refresh_plugins_dialog, refresh_printer_agent_dropdown_after_load](const PluginCapabilityId& capability) {
             if (capability.type == PluginCapabilityType::PrinterConnection)
                 NetworkAgentFactory::register_python_printer_agent(capability.plugin_key, capability.name);
             refresh_plugins_dialog();
+            refresh_printer_agent_dropdown_after_load(capability.plugin_key);
             // A newly loaded capability may satisfy a missing-plugin notification; re-validate the
             // current plate (on the UI thread) so the notification clears once its plugin is available.
             if (wxTheApp && !wxGetApp().is_closing())
@@ -2813,10 +2868,11 @@ void GUI_App::init_plugin_gui_wiring()
                 });
         });
     plugin_mgr.subscribe_on_capability_unload_callback(
-        [refresh_plugins_dialog](const PluginCapabilityId& capability) {
+        [refresh_plugins_dialog, switch_printer_agent_after_unload](const PluginCapabilityId& capability) {
             if (capability.type == PluginCapabilityType::PrinterConnection)
                 NetworkAgentFactory::deregister_python_printer_agent(capability.plugin_key, capability.name);
             refresh_plugins_dialog();
+            switch_printer_agent_after_unload(capability.plugin_key);
         });
 }
 
@@ -2835,6 +2891,9 @@ bool GUI_App::on_init_inner()
 
     ::Label::initSysFont();
 
+    // Register wxInspector plugins for Orca custom controls
+    RegisterOrcaInspectorPlugins();
+
     // Set initialization of image handlers before any UI actions - See GH issue #7469
     wxInitAllImageHandlers();
 #ifdef NDEBUG
@@ -3704,13 +3763,13 @@ bool GUI_App::on_init_network(bool try_backup)
             }
         } else {
             BOOST_LOG_TRIVIAL(info) << __FUNCTION__ << ": on_init_network, load dll failed";
-            // A failed install can leave the config naming a build that never made it to
-            // disk (download_plugin() adopts the downloaded version up front so that
-            // install_plugin() can name the library after it). If the whitelisted latest
-            // is still installed, fall back to it instead of dropping the user into the
-            // re-download flow without networking.
+            // A failed install can leave the config naming a build that never made it to disk;
+            // fall back to the installed latest instead of dropping the user into the re-download
+            // flow. Only when the configured library is genuinely absent, though - a pinned series
+            // that is on disk but failed to load once must keep its pin, not be rewritten for good.
             std::string latest = get_latest_network_version();
-            if (config_version != latest && BBLNetworkPlugin::versioned_library_exists(latest)) {
+            if (config_version != latest && !BBLNetworkPlugin::versioned_library_exists(config_version)
+                && BBLNetworkPlugin::versioned_library_exists(latest)) {
                 BOOST_LOG_TRIVIAL(warning) << __FUNCTION__ << ": falling back to installed " << latest;
                 config_version = latest;
                 app_config->set_network_plugin_version(latest);
@@ -3814,7 +3873,14 @@ bool GUI_App::on_init_network(bool try_backup)
             m_user_manager = new Slic3r::UserManager();
     }
 
-    if (should_load_networking_plugin && m_networking_compatible && !use_legacy_network_plugin()) {
+    // A version pinned to something other than the latest series is a deliberate choice, so it
+    // is exempt from the upgrade prompt the same way the legacy pin already is - otherwise the
+    // dialog reappears on every launch for as long as the pin is held.
+    const std::string pinned_version = app_config->get_network_plugin_version();
+    const bool pinned_to_older_series = !pinned_version.empty() &&
+        network_plugin_series(pinned_version) != network_plugin_series(get_latest_network_version());
+
+    if (should_load_networking_plugin && m_networking_compatible && !pinned_to_older_series) {
         app_config->clear_remind_network_update_later();
 
         if (has_network_update_available()) {
@@ -3848,6 +3914,48 @@ unsigned GUI_App::get_colour_approx_luma(const wxColour &colour)
         ));
 }
 
+void GUI_App::refresh_printer_agent_dropdown()
+{
+    if (Tab* tab = get_tab(Preset::TYPE_PRINTER))
+    {
+        if (auto* printer_tab = dynamic_cast<TabPrinter*>(tab))
+            printer_tab->refresh_printer_agent_dropdown();
+    }
+}
+
+void GUI_App::set_live_printer_agent(std::shared_ptr<IPrinterAgent> agent)
+{
+    if (!m_agent)
+        return;
+
+    // why: tearing down the old machine selection is only ever the prefix of setting the live
+    // agent (to a new one, or to null when the selection is missing) - so it lives here, not as
+    // a standalone helper. Pass nullptr to clear the selection.
+    if (DeviceManager* dev = getDeviceManager())
+    {
+        dev->set_selected_machine(""); // why: empty id disconnects and deselects the current machine
+        m_agent->set_user_selected_machine("");
+        // note: belt-and-suspenders (precedent: DeviceManagerRefresher::on_timer)
+        dev->OnSelectedMachineLost(); // why: clear stale sidebar sync-status / AMS
+        dev->clear_other_devices(); // why: drop stale LAN discoveries; keep My Devices
+    }
+
+    m_agent->set_printer_agent(agent);
+    sidebar().update_all_preset_comboboxes();
+}
+
+std::string GUI_App::resolve_printer_agent_id(const std::string& stored_id)
+{
+    if (!stored_id.empty())
+        return stored_id;
+    return (preset_bundle && preset_bundle->is_bbl_vendor()) ? BBL_PRINTER_AGENT_ID : ORCA_PRINTER_AGENT_ID;
+}
+
+std::string GUI_App::canonical_printer_agent_id(const std::string& picked_id)
+{
+    return picked_id == resolve_printer_agent_id("") ? std::string() : picked_id;
+}
+
 void GUI_App::switch_printer_agent()
 {
     if (!m_agent) {
@@ -3855,24 +3963,17 @@ void GUI_App::switch_printer_agent()
         return;
     }
 
-    // Read printer_agent from config, falling back to default
-    std::string effective_agent_id = ORCA_PRINTER_AGENT_ID;
-    if (preset_bundle->is_bbl_vendor())
-        effective_agent_id = BBL_PRINTER_AGENT_ID;
-
     const DynamicPrintConfig& config = preset_bundle->printers.get_edited_preset().config;
-    if (config.has("printer_agent")) {
-        const std::string& value = config.option<ConfigOptionString>("printer_agent")->value;
-        if (!value.empty())
-            effective_agent_id = value;
-    }
+    const std::string effective_agent_id = resolve_printer_agent_id(config.opt_string("printer_agent"));
 
     // Check if agent is registered
     const PrinterAgentInfo* agent_info_ptr = NetworkAgentFactory::get_printer_agent_info(effective_agent_id);
     if (!agent_info_ptr) {
-        BOOST_LOG_TRIVIAL(warning) << __FUNCTION__ << ": unregistered agent ID '" << effective_agent_id
-                                   << "', keeping current agent";
-        // Keep current agent, don't switch
+        // why: the selected agent's provider is gone (e.g. plugin unloaded); leaving the old
+        // live agent up would keep talking to a machine the user can no longer select.
+        BOOST_LOG_TRIVIAL(info) << __FUNCTION__ << ": agent ID '" << effective_agent_id
+                                << "' is unregistered; clearing live printer agent";
+        set_live_printer_agent(nullptr);
         return;
     }
     const PrinterAgentInfo agent_info = *agent_info_ptr;
@@ -3886,7 +3987,9 @@ void GUI_App::switch_printer_agent()
         NetworkAgentFactory::create_printer_agent_by_id(effective_agent_id, cloud_agent, log_dir);
 
     if (!new_printer_agent) {
-        BOOST_LOG_TRIVIAL(warning) << __FUNCTION__ << ": failed to create agent '" << effective_agent_id << "', keeping current agent";
+        BOOST_LOG_TRIVIAL(warning) << __FUNCTION__ << ": failed to create agent '" << effective_agent_id
+                                   << "'; clearing live printer agent";
+        set_live_printer_agent(nullptr);
         return;
     }
 
@@ -3909,9 +4012,9 @@ void GUI_App::switch_printer_agent()
         return;
     }
 
-    // Swap the agent
-    m_agent->set_printer_agent(new_printer_agent);
-    sidebar().update_all_preset_comboboxes();
+    // Swap the agent; set_live_printer_agent resets the device selection so the new
+    // agent starts clean (#124).
+    set_live_printer_agent(new_printer_agent);
 
     BOOST_LOG_TRIVIAL(info) << __FUNCTION__ << ": printer agent switched to " << effective_agent_id;
 
@@ -8181,7 +8284,7 @@ bool GUI_App::show_modal_ip_address_enter_dialog(bool input_sn, wxString title)
                 wxGetApp().app_config->save();
 
                 obj->set_dev_ip(ip_address.ToStdString());
-                obj->set_user_access_code(access_code.ToStdString());
+                obj->set_access_code(access_code.ToStdString());
             }
         }
     });

src/slic3r/GUI/GUI_App.hpp

@@ -365,9 +365,14 @@ public:
     HMSQuery* get_hms_query() { return hms_query; }
     NetworkAgent* getAgent() { return m_agent; }
 
-    // Dynamic printer agent switching
+    // Reconcile the live printer agent with the stored preset selection.
     void switch_printer_agent();
 
+    std::string resolve_printer_agent_id(const std::string& stored_id);
+    // ORCA TODO: in the future, bbl presets should specify "bbl" printer agent id
+    // then, all resolve and canonical would just be ORCA<->""
+    std::string canonical_printer_agent_id(const std::string& picked_id);
+
     FilamentColorCodeQuery* get_filament_color_code_query();
     bool is_editor() const { return m_app_mode == EAppMode::Editor; }
     bool is_gcode_viewer() const { return m_app_mode == EAppMode::GCodeViewer; }
@@ -798,6 +803,11 @@ private:
     void            window_pos_center(wxTopLevelWindow *window);
     bool            select_language();
 
+    // Dynamic printer agent selection - internal helpers for switch_printer_agent
+    // and the plugin load/unload callbacks (init_plugin_gui_wiring).
+    void refresh_printer_agent_dropdown();
+    void set_live_printer_agent(std::shared_ptr<IPrinterAgent> agent); // null clears the selection
+
     bool            config_wizard_startup();
 	void            check_updates(const bool verbose);
 

src/slic3r/GUI/GUI_Factories.cpp

@@ -123,6 +123,7 @@ std::map<std::string, std::vector<SimpleSettingData>> SettingsFactory::PART_CATE
        {"sparse_infill_density", "", 1},
        {"fill_multiline", "", 1},
        {"sparse_infill_pattern", "", 1},
+       {"sparse_infill_smooth_factor", "", 1},
        {"lateral_lattice_angle_1", "", 1},
        {"lateral_lattice_angle_2", "", 1},
        {"infill_overhang_angle", "", 1},

src/slic3r/GUI/GUI_ObjectList.cpp

@@ -3213,7 +3213,7 @@ void ObjectList::merge(bool to_multipart_object)
         //changed_object(obj_idx);
         //remove();
     }
-   /* wxGetApp().plater()->load_model_objects(objects);
+   // wxGetApp().plater()->load_model_objects(objects);
 
     Selection& selection = p->view3D->get_canvas3d()->get_selection();
     size_t last_obj_idx = p->model.objects.size() - 1;

src/slic3r/GUI/GUI_ObjectSettings.cpp

@@ -139,7 +139,7 @@ bool ObjectSettings::update_settings_list()
             optgroup->sidetext_width = 5;
 
             optgroup->m_on_change = [this, config](const t_config_option_key& opt_id, const boost::any& value) {
-                                    this->update_config_values(config);
+                                    this->update_config_values(config, opt_id);
                                     wxGetApp().obj_list()->changed_object(); };
 
             // call back for rescaling of the extracolumn control
@@ -325,7 +325,7 @@ bool ObjectSettings::add_missed_options(ModelConfig* config_to, const DynamicPri
     return is_added;
 }
 
-void ObjectSettings::update_config_values(ModelConfig* config)
+void ObjectSettings::update_config_values(ModelConfig* config, const std::string& changed_opt_key)
 {
     const auto objects_model        = wxGetApp().obj_list()->GetModel();
     const auto item                 = wxGetApp().obj_list()->GetSelection();
@@ -403,6 +403,10 @@ void ObjectSettings::update_config_values(ModelConfig* config)
     }
 
     main_config.apply(config->get(), true);
+
+    if (printer_technology == ptFFF && changed_opt_key == "layer_height")
+        config_manipulation.check_layer_height(&main_config);
+
     printer_technology == ptFFF  ?  config_manipulation.update_print_fff_config(&main_config) :
                                     config_manipulation.update_print_sla_config(&main_config) ;
 

src/slic3r/GUI/GUI_ObjectSettings.hpp

@@ -66,7 +66,7 @@ public:
      * we should add sparse_infill_pattern to avoid endless loop in update
      */
     bool        add_missed_options(ModelConfig *config_to, const DynamicPrintConfig &config_from);
-    void        update_config_values(ModelConfig *config);
+    void        update_config_values(ModelConfig *config, const std::string& changed_opt_key = "");
     void        UpdateAndShow(const bool show);
     void        msw_rescale();
     void        sys_color_changed();

src/slic3r/GUI/GUI_ObjectTableSettings.cpp

@@ -223,7 +223,7 @@ bool ObjectTableSettings::update_settings_list(bool is_object, bool is_multiple_
         std::weak_ptr<ConfigOptionsGroup> weak_optgroup(optgroup);
         optgroup->m_on_change = [this, is_object, object, config, group_category](const t_config_option_key &opt_id, const boost::any &value) {
                                     this->m_parent->Freeze();
-                                    this->update_config_values(is_object, object, config, group_category);
+                                    this->update_config_values(is_object, object, config, group_category, opt_id);
                                     wxGetApp().obj_list()->changed_object();
                                     this->m_parent->Thaw();
                                     //update_extra_column_visible_status(optgroup.get(), cat.second, config);
@@ -369,7 +369,7 @@ int ObjectTableSettings::update_extra_column_visible_status(ConfigOptionsGroup*
     return count;
 }
 
-void ObjectTableSettings::update_config_values(bool is_object, ModelObject* object, ModelConfig* config, const std::string& category)
+void ObjectTableSettings::update_config_values(bool is_object, ModelObject* object, ModelConfig* config, const std::string& category, const std::string& changed_opt_key)
 {
     int different_count = 0;
     const auto printer_technology   = wxGetApp().plater()->printer_technology();
@@ -403,6 +403,9 @@ void ObjectTableSettings::update_config_values(bool is_object, ModelObject* obje
 
     config_manipulation.set_is_BBL_Printer(wxGetApp().preset_bundle->is_bbl_vendor());
 
+    if (printer_technology == ptFFF && changed_opt_key == "layer_height")
+        config_manipulation.check_layer_height(&main_config);
+
     printer_technology == ptFFF  ?  config_manipulation.update_print_fff_config(&main_config) :
                                     config_manipulation.update_print_sla_config(&main_config) ;
 

src/slic3r/GUI/GUI_ObjectTableSettings.hpp

@@ -70,7 +70,7 @@ public:
     bool        add_missed_options(ModelConfig *config_to, const DynamicPrintConfig &config_from);
     //return visible count
     int         update_extra_column_visible_status(ConfigOptionsGroup* option_group, const std::vector<SimpleSettingData>& option_keys, ModelConfig* config);
-    void        update_config_values(bool is_object, ModelObject* object, ModelConfig* config, const std::string& category);
+    void        update_config_values(bool is_object, ModelObject* object, ModelConfig* config, const std::string& category, const std::string& changed_opt_key = "");
     void        UpdateAndShow(int row, const bool show, bool is_object, bool is_multiple_selection, ModelObject* object, ModelConfig* config, const std::string& category);
     void        ValueChanged(int row, bool is_object, ModelObject* object, ModelConfig* config, const std::string& category, const std::string& key);
     void        resetAllValues(int row, bool is_object, ModelObject* object, ModelConfig* config, const std::string& category);

src/slic3r/GUI/GUI_Utils.cpp

@@ -548,7 +548,7 @@ void RemoveButtonBorder(wxWindow* win)
     GtkCssProvider* provider = gtk_css_provider_new();
 
     const char* css =
-        "button {"
+        "button, button:hover, button:active, button:focus {"
         "  border: none;"
         "  outline: none;"
         "  box-shadow: none;"
@@ -589,6 +589,58 @@ void RemoveButtonBorder(wxWindow* win)
     );
 #endif
 }
+
+void RemoveInputBorder(wxWindow* win)
+{
+    GtkWidget* widget = win->GetHandle();
+    if (!widget) return;
+
+#if GTK_CHECK_VERSION(3, 0, 0)
+    // GTK3+: use CSS provider
+    GtkCssProvider* provider = gtk_css_provider_new();
+
+    // Target 'entry' and its inner subnodes (like text selection areas)
+    const char* css =
+        "entry, entry text, entry undershoot {"
+        "  border: none;"
+        "  outline: none;"
+        "  box-shadow: none;"
+        "  padding: 0px;"
+        "  margin: 0px;"
+        "  min-height: 0px;"
+        "  min-width: 0px;"
+        "  background: none;"
+        "}";
+
+#if GTK_CHECK_VERSION(4, 0, 0)
+    // GTK4
+    gtk_css_provider_load_from_data(provider, css, -1);
+#else
+    // GTK3
+    gtk_css_provider_load_from_data(provider, css, -1, nullptr);
+#endif
+
+    GtkStyleContext* ctx = gtk_widget_get_style_context(widget);
+    gtk_style_context_add_provider(
+        ctx,
+        GTK_STYLE_PROVIDER(provider),
+        GTK_STYLE_PROVIDER_PRIORITY_USER
+    );
+    g_object_unref(provider);
+
+#else
+    // GTK2: Target the x/y thickness of the entry widget
+    gtk_rc_parse_string(
+        "style \"no-padding-entry\" {"
+        "  xthickness = 0"
+        "  ythickness = 0"
+        "  GtkEntry::inner-border = { 0, 0, 0, 0 }"
+        "  GtkEntry::focus-line-width = 0"
+        "}"
+        "class \"GtkEntry\" style \"no-padding-entry\""
+    );
+#endif
+}
 #endif // __WXGTK__
 
 #ifdef __linux__

src/slic3r/GUI/GUI_Utils.hpp

@@ -20,6 +20,7 @@
 #include <wx/settings.h>
 #include <wx/dataview.h>
 #include <wx/statbox.h>
+#include <wx/inspector/inspector.h>
 
 #include <chrono>
 #include "Event.hpp"
@@ -88,7 +89,7 @@ void update_dark_ui(wxWindow* window);
 
 extern std::deque<wxDialog*> dialogStack;
 
-template<class P> class DPIAware : public P
+template<class P> class DPIAware : public P, public wxInspector::wxInspectable
 {
 public:
     DPIAware(wxWindow *parent, wxWindowID id, const wxString &title, const wxPoint &pos=wxDefaultPosition,
@@ -107,18 +108,12 @@ public:
         this->SetFont(m_normal_font);
 #endif
         this->CenterOnParent();
+        SetupInspectorAccelerator(this);
 #ifdef _WIN32
         update_dark_ui(this);
 #endif
 
-        // Linux specific issue : get_dpi_for_window(this) still doesn't responce to the Display's scale in new wxWidgets(3.1.3).
-        // So, calculate the m_em_unit value from the font size, as before
-#if !defined(__WXGTK__)
-        m_em_unit = std::max<size_t>(10, 10.0f * m_scale_factor);
-#else
-        // initialize default width_unit according to the width of the one symbol ("m") of the currently active font of this window.
-        m_em_unit = std::max<size_t>(10, this->GetTextExtent("m").x - 1);
-#endif // __WXGTK__
+        update_em_unit();
 
 //        recalc_font();
 
@@ -182,6 +177,11 @@ public:
 
     float   scale_factor() const        { return m_scale_factor; }
     float   prev_scale_factor() const   { return m_prev_scale_factor; }
+    // Only meant to be used by inspector, not public API
+    void    set_scale_factor(float v)      { m_scale_factor = v; }
+    void    set_prev_scale_factor(float v) { m_prev_scale_factor = v; }
+    void    set_em_unit(int v)             { m_em_unit = v; }
+    bool    force_rescale() const          { return m_force_rescale; }
 
     int     em_unit() const             { return m_em_unit; }
 //    int     font_size() const           { return m_font_size; }
@@ -228,6 +228,19 @@ private:
 //         m_em_unit = metrics.averageWidth;
 //    }
 
+    // update em_unit value for new window font
+    void update_em_unit()
+    {
+        // Linux specific issue : get_dpi_for_window(this) still doesn't responce to the Display's scale in new wxWidgets(3.1.3).
+        // So, calculate the m_em_unit value from the font size, as before
+#if !defined(__WXGTK__)
+        m_em_unit = std::max<size_t>(10, 10.0f * m_scale_factor);
+#else
+        // initialize default width_unit according to the width of the one symbol ("m") of the currently active font of this window.
+        m_em_unit = std::max<size_t>(10, this->GetTextExtent("m").x - 1);
+#endif // __WXGTK__
+    }
+
     // check if new scale is differ from previous
     bool    is_new_scale_factor() const { return fabs(m_scale_factor - m_prev_scale_factor) > 0.001; }
 
@@ -240,8 +253,7 @@ private:
         // set normal application font as a current window font
         m_normal_font = this->GetFont();
 
-        // update em_unit value for new window font
-        m_em_unit = std::max<int>(10, 10.0f * m_scale_factor);
+        update_em_unit();
 
         // rescale missed controls sizes and images
         on_dpi_changed(suggested_rect);
@@ -465,8 +477,9 @@ void dataview_remove_insets(wxDataViewCtrl* dv);
 void staticbox_remove_margin(wxStaticBox* sb);
 #endif
 
-#ifdef __WXGTK3__
-void RemoveButtonBorder(wxWindow* win);
+#ifdef __WXGTK__
+void RemoveButtonBorder(wxWindow* win);   // for wxButton/wxBitmapToggleButton based controls (SwitchButton, CheckBox)
+void RemoveInputBorder(wxWindow* win);    // for TextCtrl based controls (TextInput, ComboBox, SpinInput..)
 #endif
 
 #if defined(__WXOSX__) || defined(__linux__)

src/slic3r/GUI/Gizmos/GLGizmoBase.cpp

@@ -442,7 +442,7 @@ bool GLGizmoBase::use_grabbers(const wxMouseEvent &mouse_event) {
         }
     } else if (m_dragging) {
         // when mouse cursor leave window than finish actual dragging operation
-        bool is_leaving = mouse_event.Leaving();
+        bool is_leaving = mouse_event.Leaving() && !m_parent.has_mouse_capture(); // ORCA keep tracking mouse position while drag active and cursor not in window bounds
         if (mouse_event.Dragging()) {
             Point      mouse_coord(mouse_event.GetX(), mouse_event.GetY());
             auto       ray = m_parent.mouse_ray(mouse_coord);