Fix camera teleporting back sometimes

* For dialog without explicitly `SetMinSize`, we should use `SetSizerAndFit` instead, otherwise the dialog will not show correctly on GTK3. (OrcaSlicer/OrcaSlicer#14561)
- and if `SetSizer` is called before the full layout has been built, then an extra `SetSizeHints` should be called before layout/fit so the min size can be properly set automatically based on children's min sizes accordingly.

* Fix GTK3 dialog min size: SetSizer → SetSizerAndFit for dialogs without explicit SetMinSize

Replace SetSizer() with SetSizerAndFit() in 11 dialog constructors that
neither call SetMinSize() nor SetSizeHints(), ensuring proper minimum
size propagation from child widgets on GTK3.

SetSizerAndFit internally calls sizer->SetSizeHints(window), which
sets the window's minimum size based on children — the same fix
applied to ProjectDropDialog in 8a7662083e.

Also drop sizer->Fit(this) calls where present, since they only
resize but don't set the min size hint needed by GTK3.

Co-Authored-By: Claude <noreply@anthropic.com>

* Update code style

* Update TroubleshootDialog.hpp

* Fix unsaved preset dialog layout

* Fix MsgDialog layout

* Fix other 3 instances in MsgDialog.cpp

* Fix a few more instances

* Fix printer option dialog too big on Windows

---------

Co-authored-by: Claude <noreply@anthropic.com>
Co-authored-by: yw4z <ywsyildiz@gmail.com>

AGENTS.md

@@ -30,6 +30,7 @@ ctest --test-dir ./tests/fff_print
 - C++17, selective C++20. PascalCase classes, snake_case functions/variables
 - `#pragma once` for headers. Smart pointers and RAII preferred
 - Parallelization via TBB — be mindful of shared state
+- Always use `SetSizerAndFit(sizer)` instead of `SetSizer(sizer)` on top level window. Unless `SetSizer` must be called before the full layout is built, call `sizer->SetSizeHints(window)` afterwards in this case.
 
 ## Key Entry Points
 
@@ -59,7 +60,31 @@ ctest --test-dir ./tests/fff_print
 
 ## Localization & translations
 
-- Translation catalogs live in `localization/i18n/<lang>/OrcaSlicer_<lang>.po`.
-- When creating or reviewing translations, use the [Localization glossary](https://github.com/OrcaSlicer/OrcaSlicer_WIKI/blob/main/guides/localization_glossary.md) as the source of truth for recurring terms, so the same English term is always rendered the same way within a language and terms that must stay in English (brand/product names, acronyms, file formats, G-code, macros/variables) are not translated.
-- If a term's established translation changes, update both the affected `.po` files and the glossary so they stay in sync.
-- Only edit `msgstr` (never `msgid`); keep placeholders (`%s`, `%1%`, `\n`), context (`msgctxt`), and file encoding/line endings intact.
+Catalogs live in `localization/i18n/<lang>/OrcaSlicer_<lang>.po`; the template is `OrcaSlicer.pot`.
+See the [Localization guide](https://github.com/OrcaSlicer/OrcaSlicer_WIKI/blob/main/guides/localization_guide.md) for the human-facing version of these principles.
+
+### Terminology
+
+- Use the [Localization glossary](https://github.com/OrcaSlicer/OrcaSlicer_WIKI/blob/main/guides/localization_glossary.md) as the source of truth for recurring terms, so the same English term is always rendered the same way within a language, and terms that must stay in English (brand/product names, acronyms, materials, file formats, G-code tokens, macros/variables/identifiers) are not translated.
+- If a term's established translation changes, update both the affected `.po` files and the glossary (`localization_glossary.tsv`, then regenerate) so they stay in sync.
+- Translate the *meaning*, not the words. Check what the string actually controls before translating it — English reuses one word for different things. `Flow ratio` (multiplier), `Flow Rate` (throughput) and `Flow Dynamics` (pressure compensation) are three different terms; `extruder` may mean the toolhead, the feeder motor, or the nozzle depending on the string.
+- Reuse one template per recurring message shape (`Failed to connect to …`, `Are you sure you want to …?`), even where the English wording varies.
+
+### Editing rules
+
+- Only edit `msgstr` — **never** change `msgid`, and never "fix" wrong English in the translation alone. Report the source string instead.
+- Preserve exactly: placeholders (`%s`, `%d`, `%1%`, `%zu`, `%%`), every `\n` (count *and* position, including leading/trailing), leading/trailing spaces, HTML tags, `℃`, and the file's encoding and line endings.
+- **Never reorder positional arguments** in a `c-format` string. If the msgid is `%d` then `%s`, that order must hold — swapping them breaks at runtime.
+- `msgctxt` separates homonyms — always read it. `Back`/`Camera View` is the rear view of the 3D navigator, while `Back`/`Navigation` is the go-back button; `Top` exists in the *Alignment*, *Layers* and *Camera View* senses.
+- When a string needs disambiguating, add context in the source (`_L_CONTEXT`/`_u8L_CONTEXT`), don't work around it in the translation.
+- A literal `%` inside a string xgettext flagged `possible-c-format` will fail `msgfmt`. Fix it with a `// xgettext:no-c-format, no-boost-format` comment above the string in the source — do not mangle the translation or use `%%` in text that is never passed through printf.
+- Plural entries: read `nplurals` from the catalog's `Plural-Forms` header (it is **not** always 2 — ja/ko/zh/th/vi use 1, ru/cs/pl/lt use 3, uk uses 4). Each form must be genuinely inflected for its quantity; repeating one sentence across all forms is a bug in Slavic/Baltic languages, though it is correct for Turkish and Hungarian.
+- An entry whose `msgstr` equals its `msgid` is untranslated even though it is not empty; a plural entry with any empty form is likewise incomplete.
+- Mark machine-produced translations with an `# AI Translated` translator comment. Don't add it to a human translation you didn't actually rewrite.
+- Don't reflow or re-wrap unrelated entries — keep the diff limited to the strings you changed.
+
+### Verifying
+
+- `scripts/run_gettext.bat --full` (Windows) regenerates the template, merges every catalog and compiles the `.mo` files. It must exit 0.
+- Or check a single catalog with `msgfmt --check-format -o <out>.mo localization/i18n/<lang>/OrcaSlicer_<lang>.po`.
+- Fuzzy entries are not shown to users. If you correct one, clear its `fuzzy` flag, otherwise the fix never ships.

localization/i18n/OrcaSlicer.pot

@@ -8,7 +8,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: PACKAGE VERSION\n"
 "Report-Msgid-Bugs-To: \n"
-"POT-Creation-Date: 2026-07-23 15:24-0300\n"
+"POT-Creation-Date: 2026-07-26 21:59-0300\n"
 "PO-Revision-Date: YEAR-MO-DA HO:MI+ZONE\n"
 "Last-Translator: FULL NAME <EMAIL@ADDRESS>\n"
 "Language-Team: LANGUAGE <LL@li.org>\n"
@@ -982,7 +982,7 @@ msgstr ""
 #, possible-boost-format
 msgid ""
 "Objects(%1%) have duplicated connectors. Some connectors may be missing in slicing result.\n"
-"Please report to PrusaSlicer team in which scenario this issue happened.\n"
+"Please report to the OrcaSlicer team in which scenario this issue happened.\n"
 "Thank you."
 msgstr ""
 
@@ -3385,7 +3385,6 @@ msgstr ""
 msgid "Innerloop"
 msgstr ""
 
-#. TRN To be shown in the main menu View->Top
 msgid "Top"
 msgstr ""
 
@@ -5470,10 +5469,24 @@ msgstr ""
 msgid "Align to Y axis"
 msgstr ""
 
+msgctxt "Camera View"
+msgid "Front"
+msgstr ""
+
 msgctxt "Camera View"
 msgid "Back"
 msgstr ""
 
+#. TRN To be shown in the main menu View->Top
+msgctxt "Camera View"
+msgid "Top"
+msgstr ""
+
+#. TRN To be shown in the main menu View->Bottom
+msgctxt "Camera View"
+msgid "Bottom"
+msgstr ""
+
 msgctxt "Camera View"
 msgid "Left"
 msgstr ""
@@ -5854,19 +5867,13 @@ msgstr ""
 msgid "Top View"
 msgstr ""
 
-#. TRN To be shown in the main menu View->Bottom
-msgid "Bottom"
-msgstr ""
-
 msgid "Bottom View"
 msgstr ""
 
-msgid "Front"
-msgstr ""
-
 msgid "Front View"
 msgstr ""
 
+msgctxt "Camera View"
 msgid "Rear"
 msgstr ""
 
@@ -14729,7 +14736,7 @@ msgstr ""
 msgid "Retract amount after wipe"
 msgstr ""
 
-#, possible-c-format
+#, no-c-format, no-boost-format
 msgid ""
 "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."

localization/i18n/en/OrcaSlicer_en.po

@@ -3,7 +3,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: Orca Slicer\n"
 "Report-Msgid-Bugs-To: \n"
-"POT-Creation-Date: 2026-07-23 15:24-0300\n"
+"POT-Creation-Date: 2026-07-26 21:59-0300\n"
 "PO-Revision-Date: 2026-06-17 15:44-0300\n"
 "Last-Translator: Alexandre Folle de Menezes\n"
 "Language-Team: \n"
@@ -978,7 +978,7 @@ msgstr ""
 #, boost-format
 msgid ""
 "Objects(%1%) have duplicated connectors. Some connectors may be missing in slicing result.\n"
-"Please report to PrusaSlicer team in which scenario this issue happened.\n"
+"Please report to the OrcaSlicer team in which scenario this issue happened.\n"
 "Thank you."
 msgstr ""
 
@@ -3381,7 +3381,6 @@ msgstr ""
 msgid "Innerloop"
 msgstr ""
 
-#. TRN To be shown in the main menu View->Top
 msgid "Top"
 msgstr ""
 
@@ -5466,10 +5465,24 @@ msgstr ""
 msgid "Align to Y axis"
 msgstr ""
 
+msgctxt "Camera View"
+msgid "Front"
+msgstr ""
+
 msgctxt "Camera View"
 msgid "Back"
 msgstr ""
 
+#. TRN To be shown in the main menu View->Top
+msgctxt "Camera View"
+msgid "Top"
+msgstr ""
+
+#. TRN To be shown in the main menu View->Bottom
+msgctxt "Camera View"
+msgid "Bottom"
+msgstr ""
+
 msgctxt "Camera View"
 msgid "Left"
 msgstr ""
@@ -5850,19 +5863,13 @@ msgstr ""
 msgid "Top View"
 msgstr ""
 
-#. TRN To be shown in the main menu View->Bottom
-msgid "Bottom"
-msgstr ""
-
 msgid "Bottom View"
 msgstr ""
 
-msgid "Front"
-msgstr ""
-
 msgid "Front View"
 msgstr ""
 
+msgctxt "Camera View"
 msgid "Rear"
 msgstr ""
 
@@ -14725,7 +14732,7 @@ msgstr ""
 msgid "Retract amount after wipe"
 msgstr ""
 
-#, c-format
+#, no-c-format, no-boost-format
 msgid ""
 "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."

localization/i18n/es/OrcaSlicer_es.po

@@ -3,7 +3,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: Orca Slicer\n"
 "Report-Msgid-Bugs-To: \n"
-"POT-Creation-Date: 2026-07-23 15:24-0300\n"
+"POT-Creation-Date: 2026-07-26 21:59-0300\n"
 "PO-Revision-Date: \n"
 "Last-Translator: Ian A. Bassi <>\n"
 "Language-Team: \n"
@@ -983,11 +983,11 @@ msgstr "Conector"
 #, boost-format
 msgid ""
 "Objects(%1%) have duplicated connectors. Some connectors may be missing in slicing result.\n"
-"Please report to PrusaSlicer team in which scenario this issue happened.\n"
+"Please report to the OrcaSlicer team in which scenario this issue happened.\n"
 "Thank you."
 msgstr ""
 "Los objetos(%1%) tienen conectores duplicados. Es posible que falten algunos conectores en el resultado del laminado.\n"
-"Informe al equipo de PrusaSlicer sobre el escenario en el que se produjo este problema.\n"
+"Informe al equipo de OrcaSlicer sobre el escenario en el que se produjo este problema.\n"
 "Gracias."
 
 msgid "Cut by Plane"
@@ -3459,7 +3459,6 @@ msgstr "Recámara"
 msgid "Innerloop"
 msgstr "Bucle interno"
 
-#. TRN To be shown in the main menu View->Top
 msgid "Top"
 msgstr "Superior"
 
@@ -5630,10 +5629,27 @@ msgstr "Evitar la zona de calibración del extrusor"
 msgid "Align to Y axis"
 msgstr "Alinear con el eje Y"
 
+# AI Translated
+msgctxt "Camera View"
+msgid "Front"
+msgstr "Frontal"
+
 msgctxt "Camera View"
 msgid "Back"
 msgstr "Posterior"
 
+# AI Translated
+#. TRN To be shown in the main menu View->Top
+msgctxt "Camera View"
+msgid "Top"
+msgstr "Superior"
+
+# AI Translated
+#. TRN To be shown in the main menu View->Bottom
+msgctxt "Camera View"
+msgid "Bottom"
+msgstr "Inferior"
+
 msgctxt "Camera View"
 msgid "Left"
 msgstr "Izquierda"
@@ -6020,19 +6036,14 @@ msgstr "Vista por Defecto"
 msgid "Top View"
 msgstr "Vista superior"
 
-#. TRN To be shown in the main menu View->Bottom
-msgid "Bottom"
-msgstr "Inferior"
-
 msgid "Bottom View"
 msgstr "Vista inferior"
 
-msgid "Front"
-msgstr "Frontal"
-
 msgid "Front View"
 msgstr "Vista frontal"
 
+# AI Translated
+msgctxt "Camera View"
 msgid "Rear"
 msgstr "Posterior"
 
@@ -15490,7 +15501,7 @@ msgstr "La longitud de la retracción rápida antes de la purga, en relación co
 msgid "Retract amount after wipe"
 msgstr "Cantidad de retracción después de la limpieza"
 
-#, c-format
+#, no-c-format, no-boost-format
 msgid ""
 "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."
@@ -20733,6 +20744,15 @@ msgstr ""
 "Evita la deformación\n"
 "¿Sabías que al imprimir materiales propensos a la deformación como el ABS, aumentar adecuadamente la temperatura de la cama térmica puede reducir la probabilidad de deformaciones?"
 
+#~ msgid "Bottom"
+#~ msgstr "Inferior"
+
+#~ msgid "Front"
+#~ msgstr "Frontal"
+
+#~ msgid "Rear"
+#~ msgstr "Posterior"
+
 #~ msgid "Enter"
 #~ msgstr "Enter"
 

resources/profiles/Snapmaker/process/fdm_process_U1_common.json

@@ -70,7 +70,7 @@
 	"wipe_tower_no_sparse_layers": "0",
 	"wipe_tower_cone_angle": "30",
 	"wipe_tower_wall_type": "rib",
-	"wipe_tower_extra_rib_length": "8",
+	"wipe_tower_extra_rib_length": "0",
 	"prime_tower_width": "35",
 	"prime_volume": "30",
 	"wall_generator": "arachne",

src/libslic3r/AppConfig.cpp

@@ -233,6 +233,9 @@ void AppConfig::set_defaults()
     if (get("reverse_mouse_wheel_zoom").empty())
         set_bool("reverse_mouse_wheel_zoom", false);
 
+    if (get("infinite_camera_drag").empty())
+        set_bool("infinite_camera_drag", false);
+
     if (get("enable_append_color_by_sync_ams").empty())
         set_bool("enable_append_color_by_sync_ams", true);
     if (get("enable_merge_color_by_sync_ams").empty())

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));
 }
 
@@ -572,7 +570,7 @@ 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 +873,14 @@ 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

@@ -248,6 +248,8 @@ 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

@@ -2,7 +2,6 @@
 #define slic3r_Config_hpp_
 
 #include <assert.h>
-#include <algorithm>
 #include <map>
 #include <climits>
 #include <cfloat>
@@ -781,14 +780,10 @@ public:
                 this->values[i] = rhs_vec->values[i];
                 modified        = true;
             } else {
-                // 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()))
+                if ((i < default_index.size()) && (default_index[i] < default_value.size()))
                     this->values[i] = default_value[default_index[i]];
                 else
-                    this->values[i] = default_value[std::min(i, default_value.size() - 1)];
+                    this->values[i] = default_value[0];
             }
         }
         return modified;
@@ -2111,11 +2106,6 @@ 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
@@ -2172,12 +2162,7 @@ public:
         if (rhs->type() != this->type())
             throw ConfigurationError("ConfigOptionEnumGeneric: Assigning an incompatible type");
         // rhs could be of the following type: ConfigOptionEnumsGeneric
-        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;
+        this->values = dynamic_cast<const ConfigOptionEnumsGenericTempl *>(rhs)->values;
     }
 
     std::string serialize() const override

src/libslic3r/GCode.cpp

@@ -13,8 +13,8 @@
 #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"
@@ -889,65 +889,6 @@ 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;
-    }
-
-    // Printable-area bounds for tower-approach routing, in object coordinates (shared by
-    // the BBL avoid-perimeter path in append_tcr and the Type2 skip-points router).
-    // Multi-nozzle: clamp the 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 every existing single/dual printer keeps the historic
-    // full-printable_area routing byte-identical.
-    BoundingBox WipeTowerIntegration::printer_travel_bounds(GCode &gcodegen) const
-    {
-        const Vec2f plate_origin_2d(m_plate_origin(0), m_plate_origin(1));
-        BoundingBox printer_bbx;
-        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 {
-            Points bed_points;
-            for (const auto& p : gcodegen.m_config.printable_area.values)
-                bed_points.push_back(wipe_tower_point_to_object_point(gcodegen, p.cast<float>() + plate_origin_2d));
-            printer_bbx = BoundingBox(bed_points);
-        }
-        return printer_bbx;
-    }
-
-    // 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 the tower-local bbx corners exactly like the tcr points; a rotated
-        // tower gets a conservative axis-aligned envelope.
-        Polygon avoid_points = scaled(m_wipe_tower_bbx).polygon();
-        for (auto& p : avoid_points.points)
-            p = wipe_tower_point_to_object_point(gcodegen, transform_wt2_pt(unscale(p).cast<float>()) + plate_origin_2d);
-        BoundingBox avoid_bbx(avoid_points.points);
-        if (avoid_bbx.contains(route_start))
-            return {};
-        Polyline    travel_polyline = generate_path_to_wipe_tower(route_start, start_wipe_pos, avoid_bbx, printer_travel_bounds(gcodegen));
-        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)
@@ -1058,7 +999,6 @@ 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;
@@ -1321,7 +1261,24 @@ 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 = printer_travel_bounds(gcodegen);
+                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);
+                    }
+                }
                 {
                     // set avoid_bbx
                     avoid_bbx            = scaled(m_wipe_tower_bbx);
@@ -1351,23 +1308,20 @@ static std::vector<Vec2d> get_path_of_change_filament(const Print& print)
         }
 
         // do unretract after setting current extruder_id
-        // 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.
+        // 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.
         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 = 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;
+        float extra_unretract = is_petg_pre_extrusion ? 2.f : 0.f;
         std::string toolchange_unretract_str = (extra_unretract > 0.f) ? gcodegen.unretract(extra_unretract) : gcodegen.unretract();
         check_add_eol(toolchange_unretract_str);
 
@@ -1465,16 +1419,20 @@ 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);
 
-        // Priming lines are absolute bed moves; everything else is tower-local
-        // (transform_wt2_pt).
+        auto transform_wt_pt = [&alpha, this](const Vec2f &pt) -> Vec2f {
+            Vec2f out = Eigen::Rotation2Df(alpha) * pt;
+            out += m_wipe_tower_pos;
+            return out;
+        };
+
         Vec2f start_pos = tcr.start_pos;
         Vec2f end_pos   = tcr.end_pos;
         if (!tcr.priming) {
-            start_pos = transform_wt2_pt(start_pos);
-            end_pos   = transform_wt2_pt(end_pos);
+            start_pos = transform_wt_pt(start_pos);
+            end_pos   = transform_wt_pt(end_pos);
         }
 
-        Vec2f wipe_tower_offset   = tcr.priming ? Vec2f::Zero() : Vec2f(m_wipe_tower_pos + Eigen::Rotation2Df(alpha) * m_rib_offset);
+        Vec2f wipe_tower_offset   = tcr.priming ? Vec2f::Zero() : m_wipe_tower_pos;
         float wipe_tower_rotation = tcr.priming ? 0.f : alpha;
         Vec2f plate_origin_2d(m_plate_origin(0), m_plate_origin(1));
 
@@ -1504,22 +1462,16 @@ static std::vector<Vec2d> get_path_of_change_filament(const Print& print)
                                                              || is_ramming
                                                              || tool_change_on_wipe_tower);
 
-        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) {
+        if (should_travel_to_tower || gcodegen.m_need_change_layer_lift_z) {
             // 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();
             gcodegen.m_avoid_crossing_perimeters.use_external_mp_once();
-            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.travel_to(wipe_tower_point_to_object_point(gcodegen, start_pos + plate_origin_2d), 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 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.
+            // the tool without travelling to the tower.
         }
 
         if (will_go_down) {
@@ -1542,36 +1494,6 @@ static std::vector<Vec2d> get_path_of_change_filament(const Print& print)
                 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
-            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()};
@@ -1757,7 +1679,7 @@ 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_wt2_pt(wipe_pt) + plate_origin_2d));
+                gcodegen.m_wipe.path.points.emplace_back(wipe_tower_point_to_object_point(gcodegen, transform_wt_pt(wipe_pt) + plate_origin_2d));
         }
 
         // Let the planner know we are traveling between objects.
@@ -2883,6 +2805,7 @@ 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);
 
@@ -3203,11 +3126,20 @@ 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!
@@ -5598,7 +5530,9 @@ 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: {
@@ -5606,7 +5540,12 @@ 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;
         }
@@ -6038,41 +5977,128 @@ 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);
         }
     }
@@ -6142,7 +6168,7 @@ 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);
         }
 
@@ -6223,7 +6249,9 @@ 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;
@@ -6231,10 +6259,11 @@ 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);
                 }
@@ -6287,7 +6316,7 @@ 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;
 
@@ -6321,9 +6350,42 @@ 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;
@@ -8288,29 +8350,22 @@ 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)

src/libslic3r/GCode.hpp

@@ -132,9 +132,6 @@ private:
     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;
     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;
-    BoundingBox printer_travel_bounds(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;
@@ -542,6 +539,40 @@ 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/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). 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.
+    // 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.
     m_filament_blocks.clear();
     m_extruder_blocks.clear();
     m_machine_start_gcode_end_line_id = (unsigned int) (-1);

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

@@ -143,8 +143,7 @@ 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::Translation2d(print.wipe_tower_data().rib_offset.cast<double>()); // tower-local rib-wall shift, zero unless rib
+        Eigen::Rotation2Dd(Geometry::deg2rad(print.config().wipe_tower_rotation_angle.value));
 
     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
 {
 
@@ -20,11 +20,6 @@ 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 contrust_gap_for_skip_points(
-    const Polygon& polygon, const std::vector<Vec2f>& skip_points, float wt_width, float gap_length, Polygon& insert_skip_polygon);
 
 class WipeTower
 {
@@ -89,6 +84,7 @@ 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.
@@ -112,7 +108,6 @@ 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.
@@ -127,8 +122,6 @@ 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;
 	};
 
@@ -169,12 +162,15 @@ public:
                                    bool priming,
                                    size_t old_tool,
                                    bool is_finish,
-		                           bool is_tool_change, float purge_volume, bool is_contact) const;
+                                   bool is_tool_change,
+                                   float purge_volume,
+                                   bool is_contact = false) 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 )
@@ -188,14 +184,9 @@ 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_ec = 0.f, float wipe_volume_nc = 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 = 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);
@@ -228,6 +219,9 @@ public:
 		}
 	}
 
+	void set_wipe_volume(std::vector<std::vector<float>>& wiping_matrix) {
+		wipe_volumes = wiping_matrix;
+	}
 
 	// Switch to a next layer.
 	void set_layer(
@@ -256,6 +250,7 @@ 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;
@@ -314,9 +309,20 @@ 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_has_tpu_filament(bool has_tpu) { m_has_tpu_filament = has_tpu; }
+	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;
@@ -325,15 +331,15 @@ public:
         bool                is_support = false;
         int  			    nozzle_temperature = 0;
         int  			    nozzle_temperature_initial_layer = 0;
-        // 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;
+        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;
         float               ramming_line_width_multiplicator = 1.f;
         float               ramming_step_multiplicator = 1.f;
         float               max_e_speed = std::numeric_limits<float>::max();
@@ -343,41 +349,41 @@ public:
         float               retract_length;
         float               retract_speed;
         float               wipe_dist;
-        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;
+        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;
     };
 
 
-    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;};
-    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_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};
 	};
 
@@ -397,33 +403,25 @@ 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(bool add_solid_flag);
+	void generate_wipe_tower_blocks();
     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 ramming(int old_filament_id, int new_filament_id, bool solid_change = false, bool extruder_change = true); // extruder_chang means nozzle_change
+    NozzleChangeResult nozzle_change_new(int old_filament_id, int new_filament_id, bool solid_change = false);
     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, WipeTowerLayerType layer_type = WipeTowerLayerType::Normal);
+    ToolChangeResult   finish_block_solid(const WipeTowerBlock &block, int filament_id, bool extrude_fill = true ,bool interface_solid =false);
     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
@@ -443,6 +441,7 @@ 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
@@ -460,11 +459,12 @@ private:
     float  m_travel_speed       = 0.f;
     float  m_first_layer_speed  = 0.f;
     size_t m_first_layer_idx    = size_t(-1);
-    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
+
+    std::vector<double> m_filaments_change_length;
     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};
@@ -475,32 +475,33 @@ 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.
-    // 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_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;
-    // BBS: remove useless config
-    //bool            m_set_extruder_trimpot      = false;
+    bool            m_set_extruder_trimpot      = false;
     bool            m_adhesion                  = true;
     GCodeFlavor     m_gcode_flavor;
-    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;
+
+    // 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;
 
     // Bed properties
     enum {
@@ -511,11 +512,10 @@ 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;
 
@@ -528,52 +528,50 @@ 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;
-	// BBS
-    //const std::vector<std::vector<float>> wipe_volumes;
+	// Orca: support mmu wipe tower
+    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;
-    float           m_max_speed = 5400.f;  // the maximum printing speed on the prime tower.
-    std::vector<std::vector<Vec2f>> m_wall_skip_points;
+    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_contact_ironing = false;
-    bool                       m_has_filament_switcher = false;
-    float                      m_contact_speed   = 20 * 60.f;
-    std::vector<int>           m_physical_extruder_map;
+    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;
 	// 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 solid_toolchange);
+	Vec2f get_next_pos(const WipeTower::box_coordinates &cleaning_box, float wipe_length, bool interface_layer, size_t interface_tool);
 
     // 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, bool extruder_change) const;
+    bool is_need_reverse_travel(int filament_id, 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{
@@ -586,7 +584,6 @@ 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)
@@ -616,7 +613,7 @@ 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,
@@ -636,10 +633,13 @@ private:
 		WipeTowerWriter &writer,
 		const box_coordinates  &cleaning_box,
 		float wipe_volume);
-    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);
+    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();
 };
 
 

src/libslic3r/GCode/WipeTower2.cpp

@@ -24,6 +24,7 @@
 namespace Slic3r
 {
 
+static constexpr float      flat_iron_area                 = 4.f;
 constexpr float         flat_iron_speed                = 10.f * 60.f;
 static const double     wipe_tower_wall_infill_overlap = 0.0;
 static constexpr double WIPE_TOWER_RESOLUTION          = 0.1;
@@ -233,6 +234,24 @@ static Polygon rounding_rectangle(Polygon& polygon, double rounding = 2., double
     return res;
 }
 
+static std::pair<bool, Vec2f> ray_intersetion_line(const Vec2f& a, const Vec2f& v1, const Vec2f& b, const Vec2f& c)
+{
+    const Vec2f v2    = c - b;
+    double      denom = cross2(v1, v2);
+    if (fabs(denom) < EPSILON)
+        return {false, Vec2f(0, 0)};
+    const Vec2f v12    = (a - b);
+    double      nume_a = cross2(v2, v12);
+    double      nume_b = cross2(v1, v12);
+    double      t1     = nume_a / denom;
+    double      t2     = nume_b / denom;
+    if (t1 >= 0 && t2 >= 0 && t2 <= 1.) {
+        // Get the intersection point.
+        Vec2f res = a + t1 * v1;
+        return std::pair<bool, Vec2f>(true, res);
+    }
+    return std::pair<bool, Vec2f>(false, Vec2f{0, 0});
+}
 static Polygon scale_polygon(const std::vector<Vec2f>& points)
 {
     Polygon res;
@@ -277,7 +296,6 @@ static Polygon generate_rectange(const Line& line, coord_t offset)
     return poly;
 };
 
-// Straight or arc-fitted wall segment used by WipeTowerWriter2::generate_path().
 struct Segment
 {
     Vec2f      start;
@@ -288,6 +306,234 @@ struct Segment
     bool is_valid() const { return start.y() < end.y(); }
 };
 
+static std::vector<Segment> remove_points_from_segment(const Segment& segment, const std::vector<Vec2f>& skip_points, double range)
+{
+    std::vector<Segment> result;
+    result.push_back(segment);
+    float x = segment.start.x();
+
+    for (const Vec2f& point : skip_points) {
+        std::vector<Segment> newResult;
+        for (const auto& seg : result) {
+            if (point.y() + range <= seg.start.y() || point.y() - range >= seg.end.y()) {
+                newResult.push_back(seg);
+            } else {
+                if (point.y() - range > seg.start.y()) {
+                    newResult.push_back(Segment(Vec2f(x, seg.start.y()), Vec2f(x, point.y() - range)));
+                }
+                if (point.y() + range < seg.end.y()) {
+                    newResult.push_back(Segment(Vec2f(x, point.y() + range), Vec2f(x, seg.end.y())));
+                }
+            }
+        }
+
+        result = newResult;
+    }
+
+    result.erase(std::remove_if(result.begin(), result.end(), [](const Segment& seg) { return !seg.is_valid(); }), result.end());
+    return result;
+}
+
+struct IntersectionInfo
+{
+    Vec2f pos;
+    int   idx;
+    int   pair_idx; // gap_pair idx
+    float dis_from_idx;
+    bool  is_forward;
+};
+
+struct PointWithFlag
+{
+    Vec2f pos;
+    int   pair_idx; // gap_pair idx
+    bool  is_forward;
+};
+static IntersectionInfo move_point_along_polygon(
+    const std::vector<Vec2f>& points, const Vec2f& startPoint, int startIdx, float offset, bool forward, int pair_idx)
+{
+    float            remainingDistance = offset;
+    IntersectionInfo res;
+    int              mod = points.size();
+    if (forward) {
+        int next = (startIdx + 1) % mod;
+        remainingDistance -= (points[next] - startPoint).norm();
+        if (remainingDistance <= 0) {
+            res.idx          = startIdx;
+            res.pos          = startPoint + (points[next] - startPoint).normalized() * offset;
+            res.pair_idx     = pair_idx;
+            res.dis_from_idx = (points[startIdx] - res.pos).norm();
+            return res;
+        } else {
+            for (int i = (startIdx + 1) % mod; i != startIdx; i = (i + 1) % mod) {
+                float segmentLength = (points[(i + 1) % mod] - points[i]).norm();
+                if (remainingDistance <= segmentLength) {
+                    float ratio      = remainingDistance / segmentLength;
+                    res.idx          = i;
+                    res.pos          = points[i] + ratio * (points[(i + 1) % mod] - points[i]);
+                    res.dis_from_idx = remainingDistance;
+                    res.pair_idx     = pair_idx;
+                    return res;
+                }
+                remainingDistance -= segmentLength;
+            }
+            res.idx          = (startIdx - 1 + mod) % mod;
+            res.pos          = points[startIdx];
+            res.pair_idx     = pair_idx;
+            res.dis_from_idx = (res.pos - points[res.idx]).norm();
+        }
+    } else {
+        int next = (startIdx + 1) % mod;
+        remainingDistance -= (points[startIdx] - startPoint).norm();
+        if (remainingDistance <= 0) {
+            res.idx          = startIdx;
+            res.pos          = startPoint - (points[next] - points[startIdx]).normalized() * offset;
+            res.dis_from_idx = (res.pos - points[startIdx]).norm();
+            res.pair_idx     = pair_idx;
+            return res;
+        }
+        for (int i = (startIdx - 1 + mod) % mod; i != startIdx; i = (i - 1 + mod) % mod) {
+            float segmentLength = (points[(i + 1) % mod] - points[i]).norm();
+            if (remainingDistance <= segmentLength) {
+                float ratio      = remainingDistance / segmentLength;
+                res.idx          = i;
+                res.pos          = points[(i + 1) % mod] - ratio * (points[(i + 1) % mod] - points[i]);
+                res.dis_from_idx = segmentLength - remainingDistance;
+                res.pair_idx     = pair_idx;
+                return res;
+            }
+            remainingDistance -= segmentLength;
+        }
+        res.idx          = startIdx;
+        res.pos          = points[res.idx];
+        res.pair_idx     = pair_idx;
+        res.dis_from_idx = 0;
+    }
+    return res;
+};
+
+static void insert_points(std::vector<PointWithFlag>& pl, int idx, Vec2f pos, int pair_idx, bool is_forward)
+{
+    int   next = (idx + 1) % pl.size();
+    Vec2f pos1 = pl[idx].pos;
+    Vec2f pos2 = pl[next].pos;
+    if ((pos - pos1).squaredNorm() < EPSILON) {
+        pl[idx].pair_idx   = pair_idx;
+        pl[idx].is_forward = is_forward;
+    } else if ((pos - pos2).squaredNorm() < EPSILON) {
+        pl[next].pair_idx   = pair_idx;
+        pl[next].is_forward = is_forward;
+    } else {
+        pl.insert(pl.begin() + idx + 1, PointWithFlag{pos, pair_idx, is_forward});
+    }
+}
+
+static Polylines remove_points_from_polygon(
+    const Polygon& polygon, const std::vector<Vec2f>& skip_points, double range, bool is_left, Polygon& insert_skip_pg)
+{
+    assert(polygon.size() > 2);
+    Polylines                     result;
+    std::vector<PointWithFlag>    new_pl; // add intersection points for gaps, where bool indicates whether it's a gap point.
+    std::vector<IntersectionInfo> inter_info;
+    Vec2f                         ray          = is_left ? Vec2f(-1, 0) : Vec2f(1, 0);
+    auto                          polygon_box  = get_extents(polygon);
+    Point                         anchor_point = is_left ? Point{polygon_box.max[0], polygon_box.min[1]} : polygon_box.min; // rd:ld
+    std::vector<Vec2f>            points;
+    {
+        points.reserve(polygon.points.size());
+        int      idx      = polygon.closest_point_index(anchor_point);
+        Polyline tmp_poly = polygon.split_at_index(idx);
+        for (auto& p : tmp_poly)
+            points.push_back(unscale(p).cast<float>());
+        points.pop_back();
+    }
+
+    for (int i = 0; i < skip_points.size(); i++) {
+        for (int j = 0; j < points.size(); j++) {
+            Vec2f& p1                  = points[j];
+            Vec2f& p2                  = points[(j + 1) % points.size()];
+            auto [is_inter, inter_pos] = ray_intersetion_line(skip_points[i], ray, p1, p2);
+            if (is_inter) {
+                IntersectionInfo forward  = move_point_along_polygon(points, inter_pos, j, range, true, i);
+                IntersectionInfo backward = move_point_along_polygon(points, inter_pos, j, range, false, i);
+                backward.is_forward       = false;
+                forward.is_forward        = true;
+                inter_info.push_back(backward);
+                inter_info.push_back(forward);
+                break;
+            }
+        }
+    }
+
+    // insert point to new_pl
+    for (const auto& p : points)
+        new_pl.push_back({p, -1});
+    std::sort(inter_info.begin(), inter_info.end(), [](const IntersectionInfo& lhs, const IntersectionInfo& rhs) {
+        if (rhs.idx == lhs.idx)
+            return lhs.dis_from_idx < rhs.dis_from_idx;
+        return lhs.idx < rhs.idx;
+    });
+    for (int i = inter_info.size() - 1; i >= 0; i--) {
+        insert_points(new_pl, inter_info[i].idx, inter_info[i].pos, inter_info[i].pair_idx, inter_info[i].is_forward);
+    }
+
+    {
+        // set insert_pg for wipe_path
+        for (auto& p : new_pl)
+            insert_skip_pg.points.push_back(scaled(p.pos));
+    }
+
+    int      beg  = 0;
+    bool     skip = true;
+    int      i    = beg;
+    Polyline pl;
+
+    do {
+        if (skip || new_pl[i].pair_idx == -1) {
+            pl.points.push_back(scaled(new_pl[i].pos));
+            i    = (i + 1) % new_pl.size();
+            skip = false;
+        } else {
+            if (!pl.points.empty()) {
+                pl.points.push_back(scaled(new_pl[i].pos));
+                result.push_back(pl);
+                pl.points.clear();
+            }
+            int left = new_pl[i].pair_idx;
+            int j    = (i + 1) % new_pl.size();
+            while (j != beg && new_pl[j].pair_idx != left) {
+                if (new_pl[j].pair_idx != -1 && !new_pl[j].is_forward)
+                    left = new_pl[j].pair_idx;
+                j = (j + 1) % new_pl.size();
+            }
+            i    = j;
+            skip = true;
+        }
+    } while (i != beg);
+
+    if (!pl.points.empty()) {
+        if (new_pl[i].pair_idx == -1)
+            pl.points.push_back(scaled(new_pl[i].pos));
+        result.push_back(pl);
+    }
+    return result;
+}
+
+static Polylines contrust_gap_for_skip_points(
+    const Polygon& polygon, const std::vector<Vec2f>& skip_points, float wt_width, float gap_length, Polygon& insert_skip_polygon)
+{
+    if (skip_points.empty()) {
+        insert_skip_polygon = polygon;
+        return Polylines{to_polyline(polygon)};
+    }
+    bool        is_left = false;
+    const auto& pt      = skip_points.front();
+    if (abs(pt.x()) < wt_width / 2.f) {
+        is_left = true;
+    }
+    return remove_points_from_polygon(polygon, skip_points, gap_length, is_left, insert_skip_polygon);
+};
+
 static Polygon generate_rectange_polygon(const Vec2f& wt_box_min, const Vec2f& wt_box_max)
 {
     Polygon res;
@@ -999,12 +1245,6 @@ WipeTower::ToolChangeResult WipeTower2::construct_tcr(WipeTowerWriter2& writer,
 
 
 
-bool WipeTower2::use_gap_wall(const PrintConfig& config)
-{
-    // The cone wall has its own fully separate generator with no gap machinery.
-    return config.prime_tower_skip_points.value && config.wipe_tower_wall_type.value != wtwCone;
-}
-
 WipeTower2::WipeTower2(const PrintConfig& config, const PrintRegionConfig& default_region_config,int plate_idx, Vec3d plate_origin, const std::vector<std::vector<float>>& wiping_matrix, size_t initial_tool) :
     m_semm(config.single_extruder_multi_material.value),
     m_enable_filament_ramming(config.enable_filament_ramming.value),
@@ -1032,7 +1272,7 @@ WipeTower2::WipeTower2(const PrintConfig& config, const PrintRegionConfig& defau
     m_rib_width(config.wipe_tower_rib_width), 
     m_extra_rib_length(config.wipe_tower_extra_rib_length),
     m_wall_type((int)config.wipe_tower_wall_type),
-    m_use_gap_wall(use_gap_wall(config)),
+    m_flat_ironing(config.prime_tower_flat_ironing.value),
     m_enable_tower_interface_features(config.enable_tower_interface_features.value),
     m_enable_tower_interface_cooldown_during_tower(config.enable_tower_interface_cooldown_during_tower.value)
 {
@@ -1102,7 +1342,6 @@ void WipeTower2::set_extruder(size_t idx, const PrintConfig& config)
         m_filpar[idx].is_soluble = (idx != size_t(m_wipe_tower_filament - 1));
     else
         m_filpar[idx].is_soluble = config.filament_soluble.get_at(idx);
-    m_filpar[idx].is_support = config.filament_is_support.get_at(idx);
     m_filpar[idx].temperature = config.nozzle_temperature.get_at(idx);
     m_filpar[idx].first_layer_temperature = config.nozzle_temperature_initial_layer.get_at(idx);
     m_filpar[idx].filament_minimal_purge_on_wipe_tower = config.filament_minimal_purge_on_wipe_tower.get_at(idx);
@@ -1239,11 +1478,11 @@ std::vector<WipeTower::ToolChangeResult> WipeTower2::prime(
         toolchange_Load(writer, cleaning_box); // Prime the tool.
         if (idx_tool + 1 == tools.size()) {
             // Last tool should not be unloaded, but it should be wiped enough to become of a pure color.
-            toolchange_Wipe(writer, cleaning_box, wipe_volumes[tools[idx_tool-1]][tool], false, true);
+            toolchange_Wipe(writer, cleaning_box, wipe_volumes[tools[idx_tool-1]][tool], false);
         } else {
             // Ram the hot material out of the melt zone, retract the filament into the cooling tubes and let it cool.
             //writer.travel(writer.x(), writer.y() + m_perimeter_width, 7200);
-            toolchange_Wipe(writer, cleaning_box , 20.f, false, true);
+            toolchange_Wipe(writer, cleaning_box , 20.f, false);
             WipeTower::box_coordinates box = cleaning_box;
             box.translate(0.f, writer.y() - cleaning_box.ld.y() + m_perimeter_width);
             toolchange_Unload(writer, box , m_filpar[m_current_tool].material, m_filpar[m_current_tool].first_layer_temperature, m_filpar[tools[idx_tool + 1]].first_layer_temperature);
@@ -1286,9 +1525,8 @@ WipeTower::ToolChangeResult WipeTower2::tool_change(size_t tool)
 
     float wipe_area = 0.f;
 	float wipe_volume = 0.f;
-    float ramming_depth = 0.f;
     bool interface_layer = m_enable_tower_interface_features && m_current_layer_has_interface;
-
+	
 	// Finds this toolchange info
 	if (tool != (unsigned int)(-1))
 	{
@@ -1296,7 +1534,6 @@ WipeTower::ToolChangeResult WipeTower2::tool_change(size_t tool)
 			if ( b.new_tool == tool ) {
                 wipe_volume = b.wipe_volume;
 				wipe_area = b.required_depth;
-                ramming_depth = b.ramming_depth;
 				break;
 			}
 	}
@@ -1334,9 +1571,7 @@ WipeTower::ToolChangeResult WipeTower2::tool_change(size_t tool)
     writer.speed_override_backup();
 	writer.speed_override(100);
 
-    // On a boundary wipe start this enters at the wall gap on the first wipe row;
-    // toolchange_Unload() then climbs back up to the ram band along the box interior.
-    Vec2f initial_position = toolchange_entry_pos(m_depth_traversed, ramming_depth, is_first_layer());
+	Vec2f initial_position = cleaning_box.ld + Vec2f(0.f, m_depth_traversed);
     writer.set_initial_position(initial_position, m_wipe_tower_width, m_wipe_tower_depth, m_internal_rotation);
 
     // Increase the extruder driver current to allow fast ramming.
@@ -1345,11 +1580,6 @@ WipeTower::ToolChangeResult WipeTower2::tool_change(size_t tool)
 
     // Ram the hot material out of the melt zone, retract the filament into the cooling tubes and let it cool.
     if (tool != (unsigned int)-1){ 			// This is not the last change.
-        // Without a ram — or with the boundary wipe start, where the ram band is
-        // quantized to whole rows — the box is planned as whole wipe rows; the wipe
-        // then fills it completely so adjacent purge blocks stay contiguous. Uses the
-        // old tool (m_current_tool before toolchange_Change).
-        const bool fill_box = !tool_ramming_enabled(m_current_tool) || boundary_wipe_start_enabled(m_current_tool);
         auto new_tool_temp = is_first_layer() ? m_filpar[tool].first_layer_temperature : m_filpar[tool].temperature;
         toolchange_Unload(writer, cleaning_box, m_filpar[m_current_tool].material,
                           (is_first_layer() ? m_filpar[m_current_tool].first_layer_temperature : m_filpar[m_current_tool].temperature),
@@ -1372,7 +1602,7 @@ WipeTower::ToolChangeResult WipeTower2::tool_change(size_t tool)
                 writer.extrude_explicit(target_x, writer.y(), pre_len, 600.f);
             }
         }
-        toolchange_Wipe(writer, cleaning_box, wipe_volume, interface_layer, false, fill_box);     // Wipe the newly loaded filament until the end of the assigned wipe area.
+        toolchange_Wipe(writer, cleaning_box, wipe_volume, interface_layer);     // Wipe the newly loaded filament until the end of the assigned wipe area.
         if (interface_layer) {
             int interface_temp = m_filpar[tool].interface_print_temperature;
             if (!m_enable_tower_interface_cooldown_during_tower && interface_temp > 0 && interface_temp != base_temp)
@@ -1427,20 +1657,11 @@ void WipeTower2::toolchange_Unload(
 	float remaining = xr - xl ;							// keeps track of distance to the next turnaround
 	float e_done = 0;									// measures E move done from each segment   
 
-    const bool do_ramming = tool_ramming_enabled(m_current_tool);
+    // Orca: Do ramming when SEMM and ramming is enabled or when multi tool head when ramming is enabled on the multi tool.
+    const bool do_ramming = (m_semm && m_enable_filament_ramming) || m_filpar[m_current_tool].multitool_ramming;
     const bool cold_ramming = m_is_mk4mmu3;
-    // Orca: see set_toolchange() — quantized ram band + wipe restart at the boundary.
-    const bool boundary_wipe_start = boundary_wipe_start_enabled(m_current_tool);
-    float planned_ramming_depth = 0.f;
-    if (boundary_wipe_start && m_layer_info != m_plan.end())
-        for (const auto& tch : m_layer_info->tool_changes)
-            if (tch.old_tool == m_current_tool) { planned_ramming_depth = tch.ramming_depth; break; }
 
     if (do_ramming) {
-        if (boundary_wipe_start)
-            // The entry sits at the wall gap on the first wipe row past the reserved
-            // ram band; step inward first, then move to the band clear of the wall.
-            writer.travel(Vec2f(ramming_start_pos.x(), writer.y()));
         writer.travel(ramming_start_pos); // move to starting position
         if (! m_is_mk4mmu3)
             writer.disable_linear_advance();
@@ -1451,8 +1672,7 @@ void WipeTower2::toolchange_Unload(
         writer.set_position(ramming_start_pos);
 
     // if the ending point of the ram would end up in mid air, align it with the end of the wipe tower:
-    // (with a boundary wipe start the band is quantized to whole rows below, so no phase alignment is needed)
-    if (do_ramming && !boundary_wipe_start && (m_layer_info > m_plan.begin() && m_layer_info < m_plan.end() && (m_layer_info-1!=m_plan.begin() || !m_adhesion ))) {
+    if (do_ramming && (m_layer_info > m_plan.begin() && m_layer_info < m_plan.end() && (m_layer_info-1!=m_plan.begin() || !m_adhesion ))) {
 
         // this is y of the center of previous sparse infill border
         float sparse_beginning_y = 0.f;
@@ -1511,28 +1731,6 @@ void WipeTower2::toolchange_Unload(
 			e_done = 0;
 		}
 	}
-
-    // Orca: quantize the ram band up to the whole reserved rows (BBL quantizes the
-    // old-tool purge the same way) so no unprinted void is left between the band and
-    // the wipe restarting at the boundary below it.
-    if (planned_ramming_depth > 0.f) {
-        const int   reserved_rows = std::max(1, int(std::round(planned_ramming_depth / y_step)));
-        const float last_row_y    = ramming_start_pos.y() + (reserved_rows - 1) * y_step;
-        // Same bead model as the ramming segments above: E per mm of ram line.
-        const float e_per_mm      = 1.f / (volume_to_length(1.f, line_width, m_layer_height) * filament_area());
-        const float fill_feed     = m_filpar[m_current_tool].ramming_speed.empty() ? 3000.f :
-            60.f * volume_to_length(m_filpar[m_current_tool].ramming_speed.back(), line_width, m_layer_height);
-        while (true) {
-            const float target_x = m_left_to_right ? xr : xl;
-            if (std::abs(target_x - writer.x()) > WT_EPSILON)
-                writer.ram(writer.x(), target_x, 0.f, 0.f, e_per_mm * std::abs(target_x - writer.x()), fill_feed);
-            if (writer.y() + 0.5f * y_step > last_row_y)
-                break;
-            writer.travel(writer.x(), writer.y() + y_step, 7200);
-            m_left_to_right = !m_left_to_right;
-        }
-    }
-
 	Vec2f end_of_ramming(writer.x(),writer.y());
     writer.change_analyzer_line_width(m_perimeter_width);   // so the next lines are not affected by ramming_line_width_multiplier
 
@@ -1640,27 +1838,10 @@ void WipeTower2::toolchange_Unload(
     // this is to align ramming and future wiping extrusions, so the future y-steps can be uniform from the start:
     // the perimeter_width will later be subtracted, it is there to not load while moving over just extruded material
     Vec2f pos = Vec2f(end_of_ramming.x(), end_of_ramming.y() + (y_step/m_extra_spacing_ramming-m_perimeter_width) / 2.f + m_perimeter_width);
-    if (planned_ramming_depth > 0.f) {
-        // Orca: restart the wipe at the left-edge boundary on a fresh row below the
-        // quantized ram band so the entry scrub always runs at the wall gap (BBL keeps
-        // CP_TOOLCHANGE_WIPE starting at a box corner the same way). Same lattice
-        // formula as the no-ram branch below, offset by the ram band.
-        writer.travel(Vec2f(ramming_start_pos.x(),
-            cleaning_box.ld.y() + m_depth_traversed +
-                wipe_start_offset_after_ram(planned_ramming_depth, is_first_layer()) + m_perimeter_width), 2400.f);
-        m_left_to_right = true;
-    }
-    else if (do_ramming)
+    if (do_ramming)
         writer.travel(pos, 2400.f);
-    else {
-        // Orca: with no ram printed there is no ramming geometry to align with. Start the
-        // first wipe row so the purge row lattice continues across the block boundary
-        // (previous box's last row top edge sits at its box top): with the planned depth
-        // of rows * dy, the last row's top edge then lands exactly on this box's top and
-        // no blank band is left between adjacent purge blocks.
-        writer.set_position(Vec2f(end_of_ramming.x(),
-            cleaning_box.ld.y() + m_depth_traversed + wipe_start_offset_after_ram(0.f, is_first_layer()) + m_perimeter_width));
-    }
+    else
+        writer.set_position(pos);
 
     writer.resume_preview()
           .flush_planner_queue();
@@ -1739,9 +1920,7 @@ void WipeTower2::toolchange_Wipe(
 	WipeTowerWriter2 &writer,
 	const WipeTower::box_coordinates  &cleaning_box,
 	float wipe_volume,
-    bool interface_layer,
-    bool priming,
-    bool fill_box)
+    bool interface_layer)
 {
 	// Increase flow on first layer, slow down print.
     writer.set_extrusion_flow(m_extrusion_flow * (is_first_layer() ? 1.18f : 1.f))
@@ -1750,7 +1929,7 @@ void WipeTower2::toolchange_Wipe(
 	const float& xr = cleaning_box.rd.x();
 
     writer.set_extrusion_flow(m_extrusion_flow * m_extra_flow);
-    const float line_width = wipe_line_width();
+    const float line_width = m_perimeter_width * m_extra_flow;
     writer.change_analyzer_line_width(line_width);
 
 	// Variables x_to_wipe and traversed_x are here to be able to make sure it always wipes at least
@@ -1758,7 +1937,7 @@ void WipeTower2::toolchange_Wipe(
     // wipe until the end of the assigned area.
 
 	float x_to_wipe = volume_to_length(wipe_volume, m_perimeter_width, m_layer_height) / m_extra_flow;
-	float dy = wipe_row_spacing(is_first_layer()); // Don't use the extra spacing for the first layer, but do use the spacing resulting from increased flow.
+	float dy = (is_first_layer() ? m_extra_flow : m_extra_spacing_wipe) * m_perimeter_width; // Don't use the extra spacing for the first layer, but do use the spacing resulting from increased flow.
     // All the calculations in all other places take the spacing into account for all the layers.
 
 	// If spare layers are excluded->if 1 or less toolchange has been done, it must be sill the first layer, too.So slow down.
@@ -1771,6 +1950,9 @@ void WipeTower2::toolchange_Wipe(
         m_left_to_right = !m_left_to_right;
     }
     
+    const bool do_ironing = m_flat_ironing && (!interface_layer || !m_enable_tower_interface_features);
+    const float ironing_area = m_filpar[m_current_tool].tower_ironing_area;
+
     // now the wiping itself:
 	for (int i = 0; true; ++i)	{
 		if (i!=0) {
@@ -1781,45 +1963,22 @@ void WipeTower2::toolchange_Wipe(
 		}
 
 		float traversed_x = writer.x();
-
-        // BBS gap wall: iron the first few mm of the purge, then drag the retracted nozzle
-        // back out through the wall gap and scrub it with a dry spiral centred on the entry
-        // point so the toolchange start blob is not left on the wall (same sequence as the
-        // BBL tower's toolchange_wipe_new; the spiral self-disables when the filament's
-        // tower ironing area is 0). WT2's entry gap always sits at the left-edge entry
-        // point, so only iron when the purge actually starts there heading right (in-place
-        // toolchangers do; SEMM ram/cooling moves leave the nozzle mid-box, far from any gap).
-        if (i == 0 && m_use_gap_wall && !interface_layer && !priming && m_left_to_right &&
-            writer.x() - xl < 2.5f * line_width) {
-            float ironing_length = 3.f;
-            if (xr - writer.x() < ironing_length)
-                ironing_length = std::max(xr - writer.x(), 0.f);
-            const float retract_length = m_filpar[m_current_tool].retract_length;
-            const float retract_speed  = m_filpar[m_current_tool].retract_speed * 60.f;
-            writer.extrude(writer.x() + ironing_length, writer.y(), wipe_speed);
-            writer.retract(retract_length, retract_speed);
-            writer.travel(writer.x() - 1.5f * ironing_length, writer.y(), 600.f);
-            writer.travel(writer.x() + 0.5f * ironing_length, writer.y(), 240.f);
-            const Vec2f iron_end(writer.x() + ironing_length, writer.y());
-            writer.spiral_flat_ironing(writer.pos(), m_filpar[m_current_tool].tower_ironing_area, m_perimeter_width, flat_iron_speed);
-            writer.travel(iron_end, wipe_speed);
-            writer.retract(-retract_length, retract_speed);
-        }
-
 		if (m_left_to_right)
             writer.extrude(xr - (i % 4 == 0 ? 0 : 1.5f*line_width), writer.y(), wipe_speed);
 		else
             writer.extrude(xl + (i % 4 == 1 ? 0 : 1.5f*line_width), writer.y(), wipe_speed);
 
+        if (i == 0 && do_ironing && ironing_area > 0.f) {
+            writer.travel(writer.x(), writer.y(), 600.f);
+            writer.spiral_flat_ironing(writer.pos(), ironing_area, m_perimeter_width, 10.f * 60.f);
+        }
+
         if (writer.y()+float(EPSILON) > cleaning_box.lu.y()-0.5f*line_width)
             break;		// in case next line would not fit
 
 		traversed_x -= writer.x();
         x_to_wipe -= std::abs(traversed_x);
-        // Orca: with no ram printed the box was planned as whole wipe rows; fill it
-        // completely (quantizing the purge up to the planned rows) so the next block
-        // can start right above it without a blank band in between.
-        if (!fill_box && x_to_wipe < WT_EPSILON) {
+		if (x_to_wipe < WT_EPSILON) {
             writer.travel(m_left_to_right ? xl + 1.5f*line_width : xr - 1.5f*line_width, writer.y(), 7200);
 			break;
 		}
@@ -1951,7 +2110,7 @@ WipeTower::ToolChangeResult WipeTower2::finish_layer()
         poly = generate_support_cone_wall(writer, wt_box, feedrate, infill_cone, spacing);
     } else {
         WipeTower::box_coordinates wt_box(Vec2f(0.f, 0.f), m_wipe_tower_width, m_layer_info->depth + m_perimeter_width);
-        poly = generate_support_rib_wall(writer, wt_box, feedrate, first_layer, m_wall_type == (int)wtwRib, true);
+        poly = generate_support_rib_wall(writer, wt_box, feedrate, first_layer, m_wall_type == (int)wtwRib, true, false);
     }
 
     // brim (first layer only)
@@ -2069,32 +2228,15 @@ void WipeTower2::plan_toolchange(float z_par, float layer_height_par, unsigned i
         return;
 
     // this is an actual toolchange - let's calculate depth to reserve on the wipe tower
-    const bool first_layer_plan = (m_plan.size() - 1) == m_first_layer_idx;
-    m_plan.back().tool_changes.push_back(set_toolchange(old_tool, new_tool, layer_height_par, wipe_volume, first_layer_plan));
-}
-
-WipeTower2::WipeTowerInfo::ToolChange WipeTower2::set_toolchange(size_t old_tool, size_t new_tool, float layer_height, float wipe_volume, bool first_layer_plan)
-{
-    float width = m_wipe_tower_width - 3*m_perimeter_width;
-	float length_to_extrude = volume_to_length((m_semm ? 0.25f : m_filpar[old_tool].multitool_ramming_time) * std::accumulate(m_filpar[old_tool].ramming_speed.begin(), m_filpar[old_tool].ramming_speed.end(), 0.f),
+    float width = m_wipe_tower_width - 3*m_perimeter_width; 
+	float length_to_extrude = volume_to_length(0.25f * std::accumulate(m_filpar[old_tool].ramming_speed.begin(), m_filpar[old_tool].ramming_speed.end(), 0.f),
 										m_perimeter_width * m_filpar[old_tool].ramming_line_width_multiplicator,
-										layer_height);
-    // Orca: Reserve ramming depth only when toolchange_Unload() will actually ram,
-    // otherwise the unprinted reservation leaves blank bands between the purge boxes.
-    const bool do_ramming = tool_ramming_enabled(old_tool);
-    // Orca: with the gap wall on a multi-tool printer the ram band is quantized up to
-    // the whole reserved rows and the wipe restarts at the left-edge boundary on a
-    // fresh row below it (BBL parity: the old-tool purge is whole rows and the wipe
-    // always starts at the box corner, where the entry scrub runs).
-    const bool boundary_wipe_start = boundary_wipe_start_enabled(old_tool);
-    float ramming_depth = do_ramming ? ((int(length_to_extrude / width) + 1) * (m_perimeter_width * m_filpar[old_tool].ramming_line_width_multiplicator * m_filpar[old_tool].ramming_step_multiplicator) * m_extra_spacing_ramming) : 0;
-    // first_wipe_line rides for free on the last (partially used) ramming row, which
-    // is already covered by ramming_depth. Without ramming that row does not exist
-    // (and with a boundary wipe start the ram band is quantized to whole rows), so
-    // the whole wipe volume needs reserved wiping depth.
-    float first_wipe_line = (do_ramming && !boundary_wipe_start) ? - (width*((length_to_extrude / width)-int(length_to_extrude / width)) - width) : 0.f;
+										layer_height_par);
+    // Orca: Set ramming depth to 0 if ramming is disabled.
+    float ramming_depth = m_enable_filament_ramming ? ((int(length_to_extrude / width) + 1) * (m_perimeter_width * m_filpar[old_tool].ramming_line_width_multiplicator * m_filpar[old_tool].ramming_step_multiplicator) * m_extra_spacing_ramming) : 0;
+    float first_wipe_line = - (width*((length_to_extrude / width)-int(length_to_extrude / width)) - width);
 
-    float first_wipe_volume = length_to_volume(first_wipe_line, m_perimeter_width * m_extra_flow, layer_height);
+    float first_wipe_volume = length_to_volume(first_wipe_line, m_perimeter_width * m_extra_flow, layer_height_par);
 
     // ORCA: Keep wipe-depth planning consistent with toolchange_Wipe().
     // ORCA: On the first layer, toolchange_Wipe() advances purge rows using
@@ -2103,11 +2245,12 @@ WipeTower2::WipeTowerInfo::ToolChange WipeTower2::set_toolchange(size_t old_tool
     // ORCA: float dy = (is_first_layer() ? m_extra_flow : m_extra_spacing_wipe) * m_perimeter_width;
     // ORCA: Use the same spacing here so reserved depth matches consumed depth
     // ORCA: and first-layer purge segments do not leave visible gaps.
+    const bool first_layer_plan = (m_plan.size() - 1) == m_first_layer_idx;
     const float planning_spacing = first_layer_plan ? m_extra_flow : m_extra_spacing_wipe;
 
-    float wiping_depth = get_wipe_depth(wipe_volume - first_wipe_volume, layer_height, m_perimeter_width, m_extra_flow, planning_spacing, width);
-
-	return WipeTowerInfo::ToolChange(old_tool, new_tool, ramming_depth + wiping_depth, ramming_depth, first_wipe_line, wipe_volume);
+    float wiping_depth = get_wipe_depth(wipe_volume - first_wipe_volume, layer_height_par, m_perimeter_width, m_extra_flow, planning_spacing, width);
+    
+	m_plan.back().tool_changes.push_back(WipeTowerInfo::ToolChange(old_tool, new_tool, ramming_depth + wiping_depth, ramming_depth, first_wipe_line, wipe_volume));
 }
 
 
@@ -2145,64 +2288,49 @@ void WipeTower2::save_on_last_wipe()
             continue;
 
         // Which toolchange will finish_layer extrusions be subtracted from?
-        int idx = first_toolchange_to_nonsoluble_nonsupport(m_layer_info->tool_changes);
+        int idx = first_toolchange_to_nonsoluble(m_layer_info->tool_changes);
 
         if (idx == -1) {
             // In this case, finish_layer will be called at the very beginning.
             finish_layer().total_extrusion_length_in_plane();
         }
 
-        const float width = m_wipe_tower_width - 3*m_perimeter_width; // width we draw into
-        auto recompute_toolchange = [this, width](WipeTowerInfo::ToolChange& toolchange, float volume_to_save) {
-            float volume_left_to_wipe = std::max(m_filpar[toolchange.new_tool].filament_minimal_purge_on_wipe_tower, toolchange.wipe_volume_total - volume_to_save);
-            float volume_we_need_depth_for = std::max(0.f, volume_left_to_wipe - length_to_volume(toolchange.first_wipe_line, m_perimeter_width*m_extra_flow, m_layer_info->height));
-
-            // ORCA: Keep wipe-depth planning consistent with toolchange_Wipe().
-            // ORCA: On the first layer, toolchange_Wipe() advances purge rows using
-            // ORCA: m_extra_flow * m_perimeter_width, while later layers use
-            // ORCA: m_extra_spacing_wipe * m_perimeter_width.
-            // ORCA: float dy = (is_first_layer() ? m_extra_flow : m_extra_spacing_wipe) * m_perimeter_width;
-            // ORCA: Use the same spacing here so reserved depth matches consumed depth
-            // ORCA: and first-layer purge segments do not leave visible gaps.
-            const bool first_layer_plan = size_t(m_layer_info - m_plan.begin()) == m_first_layer_idx;
-            const float planning_spacing = first_layer_plan ? m_extra_flow : m_extra_spacing_wipe;
-
-            float depth_to_wipe = get_wipe_depth(volume_we_need_depth_for, m_layer_info->height, m_perimeter_width, m_extra_flow, planning_spacing, width);
-
-            toolchange.required_depth = toolchange.ramming_depth + depth_to_wipe;
-            toolchange.wipe_volume = volume_left_to_wipe;
-        };
-
         for (int i=0; i<int(m_layer_info->tool_changes.size()); ++i) {
             auto& toolchange = m_layer_info->tool_changes[i];
             tool_change(toolchange.new_tool);
 
             if (i == idx) {
-                recompute_toolchange(toolchange, length_to_volume(finish_layer().total_extrusion_length_in_plane(), m_perimeter_width, m_layer_info->height));
-            } else if (toolchange.wipe_volume < m_filpar[toolchange.new_tool].filament_minimal_purge_on_wipe_tower) {
-                // Keep filament_minimal_purge_on_wipe_tower enforced for toolchanges that get
-                // no finish-layer saving, e.g. a support/soluble filament skipped as the
-                // finish filament above. Recomputing only when the clamp binds leaves all
-                // other toolchanges with their planned values bit-for-bit.
-                recompute_toolchange(toolchange, 0.f);
+                float width = m_wipe_tower_width - 3*m_perimeter_width; // width we draw into
+
+                float volume_to_save = length_to_volume(finish_layer().total_extrusion_length_in_plane(), m_perimeter_width, m_layer_info->height);
+                float volume_left_to_wipe = std::max(m_filpar[toolchange.new_tool].filament_minimal_purge_on_wipe_tower, toolchange.wipe_volume_total - volume_to_save);
+                float volume_we_need_depth_for = std::max(0.f, volume_left_to_wipe - length_to_volume(toolchange.first_wipe_line, m_perimeter_width*m_extra_flow, m_layer_info->height));
+                
+                // ORCA: Keep wipe-depth planning consistent with toolchange_Wipe().
+                // ORCA: On the first layer, toolchange_Wipe() advances purge rows using
+                // ORCA: m_extra_flow * m_perimeter_width, while later layers use
+                // ORCA: m_extra_spacing_wipe * m_perimeter_width.
+                // ORCA: float dy = (is_first_layer() ? m_extra_flow : m_extra_spacing_wipe) * m_perimeter_width;
+                // ORCA: Use the same spacing here so reserved depth matches consumed depth
+                // ORCA: and first-layer purge segments do not leave visible gaps.
+                const bool first_layer_plan = size_t(m_layer_info - m_plan.begin()) == m_first_layer_idx;
+                const float planning_spacing = first_layer_plan ? m_extra_flow : m_extra_spacing_wipe;
+                
+                float depth_to_wipe = get_wipe_depth(volume_we_need_depth_for, m_layer_info->height, m_perimeter_width, m_extra_flow, planning_spacing, width);
+
+                toolchange.required_depth = toolchange.ramming_depth + depth_to_wipe;
+                toolchange.wipe_volume = volume_left_to_wipe;
             }
         }
     }
 }
 
 
-// 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.
-// Like WipeTower::first_toolchange_to_nonsoluble_nonsupport(): support and soluble
-// filaments bond poorly to the material printed on top of them, so they must not
-// print the tower's shell when another filament is available on the layer.
-int WipeTower2::first_toolchange_to_nonsoluble_nonsupport(
+// Return index of first toolchange that switches to non-soluble extruder
+// ot -1 if there is no such toolchange.
+int WipeTower2::first_toolchange_to_nonsoluble(
         const std::vector<WipeTowerInfo::ToolChange>& tool_changes) const
 {
-    if (tool_changes.empty())
-        return -1;
-
     // If a specific wipe tower filament is forced, use it to decide where to finish the layer.
     if (m_wipe_tower_filament > 0) {
         for (size_t idx = 0; idx < tool_changes.size(); ++idx) {
@@ -2211,19 +2339,8 @@ int WipeTower2::first_toolchange_to_nonsoluble_nonsupport(
         }
         return -1;
     }
-
-    auto is_wall_filament = [this](size_t tool) {
-        return !m_filpar[tool].is_soluble && !m_filpar[tool].is_support;
-    };
-    for (size_t idx = 0; idx < tool_changes.size(); ++idx)
-        if (is_wall_filament(tool_changes[idx].new_tool))
-            return idx;
-    if (is_wall_filament(tool_changes.front().old_tool))
-        return -1;
-    // Only support/soluble filaments on this layer: keep the first toolchange so the
-    // finish-layer saving and the minimal-purge clamp still apply to it (Orca depth
-    // and wipe volume accounting, see save_on_last_wipe()).
-    return 0;
+    // Orca: allow calculation of the required depth and wipe volume for soluble toolchanges as well.
+    return tool_changes.empty() ? -1 : 0;
 }
 
 static WipeTower::ToolChangeResult merge_tcr(WipeTower::ToolChangeResult& first,
@@ -2246,24 +2363,6 @@ static WipeTower::ToolChangeResult merge_tcr(WipeTower::ToolChangeResult& first,
 }
 
 
-// Precompute, for every plan layer, the wall openings ("skip points") at each toolchange's
-// entry position, like WipeTower::get_all_wall_skip_points(). toolchange_entry_pos()
-// reproduces from the finalized plan where tool_change() will start, so each gap coincides
-// with the entry travel's target (tcr.start_pos, pre-rotation frame). BBL parity: the gap
-// sits at the CP_TOOLCHANGE_WIPE start row, never at the ram band.
-void WipeTower2::compute_wall_skip_points()
-{
-    m_wall_skip_points.assign(m_plan.size(), std::vector<Vec2f>());
-    for (size_t layer_id = 0; layer_id < m_plan.size(); ++layer_id) {
-        float depth_traversed = 0.f;
-        for (const auto& toolchange : m_plan[layer_id].tool_changes) {
-            m_wall_skip_points[layer_id].emplace_back(
-                toolchange_entry_pos(depth_traversed, toolchange.ramming_depth, layer_id == m_first_layer_idx));
-            depth_traversed += toolchange.required_depth;
-        }
-    }
-}
-
 // Processes vector m_plan and calls respective functions to generate G-code for the wipe tower
 // Resulting ToolChangeResults are appended into vector "result"
 void WipeTower2::generate(std::vector<std::vector<WipeTower::ToolChangeResult>> &result)
@@ -2279,41 +2378,12 @@ void WipeTower2::generate(std::vector<std::vector<WipeTower::ToolChangeResult>>
     }
 #endif
 
-    if (m_wall_type == (int)wtwRib) {
-        // Rib wall: force a square tower like WipeTower::plan_tower_new(), ignoring the
-        // configured prime_tower_width (the GUI greys it out in rib mode). The planned depths
-        // already include the extra-spacing factors, so sqrt(depth * width) preserves the
-        // purge area. Replan every toolchange for the new width, then re-derive the depths.
-        float max_depth = 0.f;
-        for (const auto& current_plan : m_plan)
-            max_depth = std::max(max_depth, current_plan.depth);
-        if (max_depth > EPSILON) {
-            m_wipe_tower_width = align_ceil(std::sqrt(max_depth * m_wipe_tower_width), m_perimeter_width);
-            for (size_t idx = 0; idx < m_plan.size(); ++idx)
-                for (auto& toolchange : m_plan[idx].tool_changes)
-                    toolchange = set_toolchange(toolchange.old_tool, toolchange.new_tool,
-                                                m_plan[idx].height, toolchange.wipe_volume,
-                                                idx == m_first_layer_idx);
-            plan_tower();
-        }
-
-        // Like WipeTower::plan_tower_new(): extend the ribs instead of the tower when the
-        // tower is smaller than the height-based stability minimum.
-        const float min_depth = WipeTower::get_limit_depth_by_height(m_wipe_tower_height);
-        if (m_wipe_tower_depth + EPSILON < min_depth)
-            m_rib_length = std::max(m_rib_length, min_depth * (float)std::sqrt(2.f));
-    }
-
-    const float diagonal = std::sqrt(m_wipe_tower_depth * m_wipe_tower_depth + m_wipe_tower_width * m_wipe_tower_width);
-    m_rib_length = std::max(m_rib_length, diagonal);
+    m_rib_length = std::max({m_rib_length, sqrt(m_wipe_tower_depth * m_wipe_tower_depth + m_wipe_tower_width * m_wipe_tower_width)});
     m_rib_length += m_extra_rib_length;
-    m_rib_length = std::max(diagonal, m_rib_length); // a negative extra length must not shrink the ribs below the diagonal
+    m_rib_length = std::max(0.f, m_rib_length);
     m_rib_width  = std::min(m_rib_width, std::min(m_wipe_tower_depth, m_wipe_tower_width) /
                                              2.f); // Ensure that the rib wall of the wipetower are attached to the infill.
 
-    if (m_use_gap_wall)
-        compute_wall_skip_points();
-
     m_layer_info = m_plan.begin();
     m_current_height = 0.f;
 
@@ -2340,7 +2410,7 @@ void WipeTower2::generate(std::vector<std::vector<WipeTower::ToolChangeResult>>
         if (m_layer_info->depth < m_wipe_tower_depth - m_perimeter_width)
 			m_y_shift = (m_wipe_tower_depth-m_layer_info->depth-m_perimeter_width)/2.f;
 
-        int idx = first_toolchange_to_nonsoluble_nonsupport(layer.tool_changes);
+        int idx = first_toolchange_to_nonsoluble(layer.tool_changes);
         WipeTower::ToolChangeResult finish_layer_tcr;
 
         if (idx == -1) {
@@ -2433,7 +2503,8 @@ Polygon WipeTower2::generate_support_rib_wall(WipeTowerWriter2&
                                              double                 feedrate,
                                              bool                   first_layer,
                                              bool                   rib_wall,
-                                             bool                   extrude_perimeter)
+                                             bool                   extrude_perimeter,
+                                             bool                   skip_points)
 {
 
     float     retract_length = m_filpar[m_current_tool].retract_length;
@@ -2453,28 +2524,18 @@ Polygon WipeTower2::generate_support_rib_wall(WipeTowerWriter2&
     if (!extrude_perimeter)
         return wall_polygon;
 
-    if (m_use_gap_wall) {
-        // Cut the wall open at each toolchange's entry (see compute_wall_skip_points()).
-        // The vector is empty during the save_on_last_wipe planning passes, which therefore
-        // measure the un-gapped wall — same approximation as the BBL tower.
-        static const std::vector<Vec2f> no_skip_points;
-        const size_t layer_id = size_t(m_layer_info - m_plan.begin());
-        const std::vector<Vec2f>& layer_skip_points =
-            layer_id < m_wall_skip_points.size() ? m_wall_skip_points[layer_id] : no_skip_points;
-        result_wall = contrust_gap_for_skip_points(wall_polygon, layer_skip_points, m_wipe_tower_width, 2.5 * m_perimeter_width,
+    if (skip_points) {
+        result_wall = contrust_gap_for_skip_points(wall_polygon, std::vector<Vec2f>(), m_wipe_tower_width, 2.5 * m_perimeter_width,
                                                    insert_skip_polygon);
     } else {
         result_wall.push_back(to_polyline(wall_polygon));
         insert_skip_polygon = wall_polygon;
     }
     writer.generate_path(result_wall, feedrate, retract_length, retract_speed, m_used_fillet);
-    // Tower-local shift that puts the rib wall's protruding first-layer min corner at the
-    // configured tower position, like WipeTower::generate_support_wall_new(). Measured on
-    // the un-gapped outline so a wall gap cannot shift the tower.
-    if (rib_wall && is_first_layer()) {
-        BoundingBox bbox = get_extents(insert_skip_polygon);
-        m_rib_offset     = Vec2f(-unscaled<float>(bbox.min.x()), -unscaled<float>(bbox.min.y()));
-    }
+    //if (m_cur_layer_id == 0) {
+    //    BoundingBox bbox = get_extents(result_wall);
+    //    m_rib_offset     = Vec2f(-unscaled<float>(bbox.min.x()), -unscaled<float>(bbox.min.y()));
+    //}
 
     return insert_skip_polygon;
 }

src/libslic3r/GCode/WipeTower2.hpp

@@ -34,10 +34,6 @@ 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);
-
 	// 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 )
@@ -73,9 +69,9 @@ 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));
     }
-    // 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; }
+    // 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(); }
     float get_rib_width() const { return m_rib_width; }
     float get_rib_length() const { return m_rib_length; }
 
@@ -153,7 +149,6 @@ 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;
@@ -225,6 +220,7 @@ 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_prev_layer_had_interface = false;
@@ -235,12 +231,6 @@ 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;
 
@@ -288,37 +278,6 @@ 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
 	{
@@ -369,10 +328,9 @@ private:
     std::vector<float> m_used_filament_length;
 	std::vector<std::pair<float, std::vector<float>>> m_used_filament_length_until_layer;
 
-    // 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(
+    // Return index of first toolchange that switches to non-soluble extruder
+    // ot -1 if there is no such toolchange.
+    int first_toolchange_to_nonsoluble(
             const std::vector<WipeTowerInfo::ToolChange>& tool_changes) const;
 
 	void toolchange_Unload(
@@ -395,9 +353,7 @@ private:
 		WipeTowerWriter2 &writer,
 		const WipeTower::box_coordinates  &cleaning_box,
 		float wipe_volume,
-        bool interface_layer,
-        bool priming = false,
-        bool fill_box = false);
+        bool interface_layer);
 
 
     Polygon generate_support_rib_wall(WipeTowerWriter2&                 writer,
@@ -405,7 +361,8 @@ private:
                                       double                 feedrate,
                                       bool                   first_layer,
                                       bool                   rib_wall,
-                                      bool                   extrude_perimeter);
+                                      bool                   extrude_perimeter,
+                                      bool                   skip_points);
 
     Polygon generate_support_cone_wall(
         WipeTowerWriter2& writer, 
@@ -415,12 +372,6 @@ 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/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);
-    void reset_to_linear_move();
-    //BBS:
+    //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/Print.cpp

@@ -3409,11 +3409,7 @@ 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]);
-            // 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_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");
         }
 
         m_full_print_config = m_ori_full_print_config;
@@ -4021,33 +4017,10 @@ 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());
-        // 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);
-        }
+        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());
         // 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.
@@ -4083,19 +4056,27 @@ void Print::_make_wipe_tower()
             multi_extruder_flush.emplace_back(wipe_volumes);
         }
 
-        // 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.
+        // 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();
         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
-        {
-            auto nozzle = nozzle_group_result.get_nozzle_for_filament(current_filament_id, layer_idx);
+        if (group_result) {
+            auto 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
@@ -4114,8 +4095,8 @@ void Print::_make_wipe_tower()
                 float volume_to_purge = 0;
 
                 // Per-carousel-slot purge tracking via NozzleStatusRecorder
-                {
-                    auto nozzle_info = nozzle_group_result.get_nozzle_for_filament(filament_id, layer_idx);
+                if (group_result) {
+                    auto nozzle_info = 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;
@@ -4134,6 +4115,22 @@ 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.
@@ -4141,21 +4138,29 @@ 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);
 
-                // Prime volume per-filament: the tower now picks extruder-change vs nozzle-change
-                // (carousel) internally per plan layer, so pass both candidates (BBS pattern).
+                // Select prime volume per-filament: nozzle change (carousel rotation) uses
+                // filament_prime_volume_nc, filament change (same nozzle slot) uses filament_prime_volume.
                 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) {
-                    wipe_volume_ec = 15.f;
-                    wipe_volume_nc = 15.f;
+                    prime_volume = 15.f;
                 }
 
                 wipe_tower.plan_toolchange((float)layer_tools.print_z, (float)layer_tools.wipe_tower_layer_height, current_filament_id, filament_id,
-                    wipe_volume_ec, wipe_volume_nc, volume_to_purge);
+                    prime_volume, volume_to_purge);
                 current_filament_id = filament_id;
             }
             layer_tools.wiping_extrusions().ensure_perimeters_infills_order(*this);
@@ -4333,12 +4338,7 @@ 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();
-        // 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(),
+        m_fake_wipe_tower.set_fake_extrusion_data(wipe_tower.position(), 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

@@ -1355,11 +1355,7 @@ 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]);
-        // 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;
+        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");
     }
 
     // Do not use the ApplyStatus as we will use the max function when updating apply_status.
@@ -1415,16 +1411,6 @@ 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

@@ -331,6 +331,8 @@ 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)
 
@@ -1999,12 +2001,30 @@ 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));
 
@@ -5629,6 +5649,7 @@ 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 = "%";
@@ -10495,44 +10516,6 @@ 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)
 {
@@ -10574,8 +10557,6 @@ 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,
 };
 

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/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/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);

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/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/GLCanvas3D.cpp

@@ -4535,6 +4535,16 @@ void GLCanvas3D::on_mouse(wxMouseEvent& evt)
     else if (evt.Dragging() || is_camera_rotate(evt, button_mappings) || is_camera_pan(evt, button_mappings)) {
         m_mouse.dragging = true;
 
+        // Orca: this event reports the position the pointer was teleported to by the infinite
+        // camera drag. Restart the drag from there, so the jump is not turned into a camera
+        // movement. Dropping the origin also keeps the drag consistent on platforms which
+        // silently ignore the warp request (Wayland), where the pointer never actually moved.
+        if (m_mouse.drag.pointer_wrapped) {
+            m_mouse.drag.pointer_wrapped = false;
+            m_mouse.set_start_position_2D_as_invalid();
+            m_mouse.set_start_position_3D_as_invalid();
+        }
+
         if (m_layers_editing.state != LayersEditing::Unknown && layer_editing_object_idx != -1) {
             if (m_layers_editing.state == LayersEditing::Editing) {
                 _perform_layer_editing_action(&evt);
@@ -4616,6 +4626,7 @@ void GLCanvas3D::on_mouse(wxMouseEvent& evt)
                 camera.auto_type(Camera::EType::Perspective);
                 m_dirty = true;
                 m_mouse.ignore_right_up = true;  // will be reset on button up event even if not right button is pressed
+                _wrap_mouse_pointer_on_canvas_border(pos, Point(m_mouse.drag.start_position_3D.x(), m_mouse.drag.start_position_3D.y()));
             }
 
             m_camera_movement = true;
@@ -4642,6 +4653,7 @@ void GLCanvas3D::on_mouse(wxMouseEvent& evt)
                 camera.set_target(camera.get_target() + orig - cur_pos);
                 m_dirty = true;
                 m_mouse.ignore_right_up = true;  // will be reset on button up event even if not right button is pressed
+                _wrap_mouse_pointer_on_canvas_border(pos, m_mouse.drag.start_position_2D);
             }
 
             m_camera_movement = true;
@@ -5529,6 +5541,7 @@ void GLCanvas3D::mouse_up_cleanup()
     m_moving = false;
     m_camera_movement = false;
     m_mouse.drag.move_volume_idx = -1;
+    m_mouse.drag.pointer_wrapped = false;
     m_mouse.set_start_position_3D_as_invalid();
     m_mouse.set_start_position_2D_as_invalid();
     m_mouse.dragging = false;
@@ -6047,10 +6060,10 @@ 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());
 
@@ -10226,6 +10239,55 @@ Vec3d GLCanvas3D::_mouse_to_bed_3d(const Point& mouse_pos)
     return mouse_ray(mouse_pos).intersect_plane(0.0);
 }
 
+// Orca: Blender-like infinite camera drag. Once a pan/orbit drag drives the pointer into a canvas
+// border it is teleported to the opposite one, so that the movement is only limited by how long
+// the user keeps dragging and not by the window (or screen) bounds. prev_pos is the position the
+// drag is coming from, which tells which border the pointer is being pushed against.
+// The drag is flagged instead of being offset by the jump, because the warp request is not
+// honoured everywhere - Wayland compositors ignore it, in which case the pointer stays at the
+// border and the drag simply stops there, exactly as it does with this feature disabled.
+void GLCanvas3D::_wrap_mouse_pointer_on_canvas_border(const Point& mouse_pos, const Point& prev_pos)
+{
+    if (m_canvas == nullptr || !wxGetApp().app_config->get_bool("infinite_camera_drag"))
+        return;
+
+    const Size cnv_size = get_canvas_size();
+
+    auto wrapped_coord = [](int coord, int prev_coord, int size) {
+        // The pointer is teleported once it comes this close to a border. The margin is
+        // proportional to the canvas because the pointer can travel a long way between two
+        // motion events of a fast drag, and a thin border would be stepped over.
+        const int border = std::clamp(size / 32, 12, 48);
+        // It then lands this far from the opposite border. A fixed inset is used rather than the
+        // mirrored crossing point: the latter leaves the pointer as close to the opposite border
+        // as it just came to this one, so grazing a border would wrap back and forth.
+        const int inset = std::clamp(size / 8, 48, 160);
+        // Nothing to wrap into if the canvas is too small to land clear of both borders.
+        if (size <= 2 * inset)
+            return coord;
+        // Only the axis the drag actually pushes into a border is wrapped, so that panning along
+        // a border - horizontally over the bottom of the canvas, say - does not wrap the other one.
+        if (coord > size - border && coord > prev_coord)
+            return inset;
+        if (coord < border && coord < prev_coord)
+            return size - inset;
+        return coord;
+    };
+
+    const Point wrapped(wrapped_coord(static_cast<int>(mouse_pos.x()), static_cast<int>(prev_pos.x()), cnv_size.get_width()),
+                        wrapped_coord(static_cast<int>(mouse_pos.y()), static_cast<int>(prev_pos.y()), cnv_size.get_height()));
+    if (wrapped == mouse_pos)
+        return;
+
+    Vec2d logical_pos = wrapped.cast<double>();
+#if ENABLE_RETINA_GL
+    const double factor = m_retina_helper->get_scale_factor();
+    logical_pos /= factor;
+#endif // ENABLE_RETINA_GL
+    m_canvas->WarpPointer(static_cast<int>(std::lround(logical_pos.x())), static_cast<int>(std::lround(logical_pos.y())));
+    m_mouse.drag.pointer_wrapped = true;
+}
+
 // While it looks like we can call
 // this->reload_scene(true, true)
 // the two functions are quite different:

src/slic3r/GUI/GLCanvas3D.hpp

@@ -333,6 +333,9 @@ class GLCanvas3D
             int move_volume_idx{ -1 };
             bool move_requires_threshold{ false };
             Point move_start_threshold_position_2D{ Invalid_2D_Point };
+            // Orca: set when the pointer has been teleported to the opposite canvas border
+            // by the infinite camera drag, see GLCanvas3D::_wrap_mouse_pointer_on_canvas_border()
+            bool pointer_wrapped{ false };
         };
 
         bool dragging{ false };
@@ -1221,6 +1224,10 @@ public:
 private:
     bool _is_shown_on_screen() const;
 
+    // Orca: teleports the pointer to the opposite canvas border when a camera drag pushes it
+    // into one, so that panning/orbiting is not limited by the window bounds.
+    void _wrap_mouse_pointer_on_canvas_border(const Point& mouse_pos, const Point& prev_pos);
+
     void _update_slice_error_status();
 
     void _switch_toolbars_icon_filename();

src/slic3r/GUI/Gizmos/GLGizmoCut.cpp

@@ -3502,7 +3502,7 @@ static void check_objects_after_cut(const ModelObjectPtrs& objects)
         names += ", " + from_u8(err_objects_names[i]);
     WarningDialog(wxGetApp().plater(), format_wxstr(_L("Objects(%1%) have duplicated connectors. "
                                 "Some connectors may be missing in slicing result.\n"
-                                "Please report to PrusaSlicer team in which scenario this issue happened.\n"
+                                "Please report to the OrcaSlicer team in which scenario this issue happened.\n"
                                 "Thank you."), names)).ShowModal();
 }
 

src/slic3r/GUI/MainFrame.cpp

@@ -2654,14 +2654,14 @@ static void add_common_view_menu_items(wxMenu* view_menu, MainFrame* mainFrame,
         "", nullptr, [can_change_view]() { return can_change_view(); }, mainFrame);
     //view_menu->AppendSeparator();
     //TRN To be shown in the main menu View->Top
-    append_menu_item(view_menu, wxID_ANY, _L("Top") + "\t" + ctrl + "1", _L("Top View"), [mainFrame](wxCommandEvent&) { mainFrame->select_view("top"); },
+    append_menu_item(view_menu, wxID_ANY, _L_CONTEXT("Top", "Camera View") + "\t" + ctrl + "1", _L("Top View"), [mainFrame](wxCommandEvent&) { mainFrame->select_view("top"); },
         "", nullptr, [can_change_view]() { return can_change_view(); }, mainFrame);
     //TRN To be shown in the main menu View->Bottom
-    append_menu_item(view_menu, wxID_ANY, _L("Bottom") + "\t" + ctrl + "2", _L("Bottom View"), [mainFrame](wxCommandEvent&) { mainFrame->select_view("bottom"); },
+    append_menu_item(view_menu, wxID_ANY, _L_CONTEXT("Bottom", "Camera View") + "\t" + ctrl + "2", _L("Bottom View"), [mainFrame](wxCommandEvent&) { mainFrame->select_view("bottom"); },
         "", nullptr, [can_change_view]() { return can_change_view(); }, mainFrame);
-    append_menu_item(view_menu, wxID_ANY, _L("Front") + "\t" + ctrl + "3", _L("Front View"), [mainFrame](wxCommandEvent&) { mainFrame->select_view("front"); },
+    append_menu_item(view_menu, wxID_ANY, _L_CONTEXT("Front", "Camera View") + "\t" + ctrl + "3", _L("Front View"), [mainFrame](wxCommandEvent&) { mainFrame->select_view("front"); },
         "", nullptr, [can_change_view]() { return can_change_view(); }, mainFrame);
-    append_menu_item(view_menu, wxID_ANY, _L("Rear") + "\t" + ctrl + "4", _L("Rear View"), [mainFrame](wxCommandEvent&) { mainFrame->select_view("rear"); },
+    append_menu_item(view_menu, wxID_ANY, _L_CONTEXT("Rear", "Camera View") + "\t" + ctrl + "4", _L("Rear View"), [mainFrame](wxCommandEvent&) { mainFrame->select_view("rear"); },
         "", nullptr, [can_change_view]() { return can_change_view(); }, mainFrame);
     append_menu_item(view_menu, wxID_ANY, _L_CONTEXT("Left", "Camera View") + "\t" + ctrl + "5", _L("Left View"),[mainFrame](wxCommandEvent &) {mainFrame->select_view("left"); },
         "", nullptr, [can_change_view]() { return can_change_view(); }, mainFrame);

src/slic3r/GUI/MsgDialog.cpp

@@ -65,7 +65,7 @@ MsgDialog::MsgDialog(wxWindow *parent, const wxString &title, const wxString &he
     main_sizer->Add(btn_sizer, 0, wxBOTTOM | wxRIGHT | wxEXPAND | wxTOP, FromDIP(10));
 
     apply_style(style);
-	SetSizerAndFit(main_sizer);
+	SetSizer(main_sizer);
     wxGetApp().UpdateDlgDarkUI(this);
 }
 
@@ -221,6 +221,7 @@ void MsgDialog::apply_style(long style)
 
 void MsgDialog::finalize()
 {
+    GetSizer()->SetSizeHints(this);
     Layout();
     Fit();
     CenterOnParent();
@@ -547,7 +548,7 @@ DeleteConfirmDialog::DeleteConfirmDialog(wxWindow *parent, const wxString &title
     m_del_btn->Bind(wxEVT_BUTTON, [this](wxCommandEvent &e) { EndModal(wxID_OK); });
     m_cancel_btn->Bind(wxEVT_BUTTON, [this](wxCommandEvent &e) { EndModal(wxID_CANCEL); });
 
-    SetSizer(m_main_sizer);
+    SetSizerAndFit(m_main_sizer);
     Layout();
     Fit();
     wxGetApp().UpdateDlgDarkUI(this);
@@ -582,7 +583,7 @@ Newer3mfVersionDialog::Newer3mfVersionDialog(wxWindow *parent, const Semver *fil
     main_sizer->Add(content_sizer, 0, wxEXPAND | wxALL, FromDIP(5));
     main_sizer->Add(get_btn_sizer(), 0, wxEXPAND | wxALL, FromDIP(5));
 
-    this->SetSizer(main_sizer);
+    this->SetSizerAndFit(main_sizer);
     Layout();
     Fit();
     wxGetApp().UpdateDlgDarkUI(this);
@@ -745,9 +746,8 @@ NetworkErrorDialog::NetworkErrorDialog(wxWindow* parent)
     sizer_main->Add(sizer_button, 1, wxEXPAND | wxLEFT | wxRIGHT, 15);
     sizer_main->Add(0, 0, 0, wxTOP, 18);
 
-    SetSizer(sizer_main);
+    SetSizerAndFit(sizer_main);
     Layout();
-    sizer_main->Fit(this);
     Centre(wxBOTH);
 }
 

src/slic3r/GUI/NetworkPluginDialog.cpp

@@ -47,6 +47,7 @@ NetworkPluginDownloadDialog::NetworkPluginDownloadDialog(wxWindow* parent, Mode
     } else {
         create_missing_plugin_ui();
     }
+    main_sizer->SetSizeHints(this);
     Layout();
     Fit();
     CentreOnParent();

src/slic3r/GUI/NetworkTestDialog.cpp

@@ -47,7 +47,7 @@ NetworkTestDialog::NetworkTestDialog(wxWindow* parent, wxWindowID id, const wxSt
 
 	init_bind();
 
-	this->SetSizer(main_sizer);
+	this->SetSizerAndFit(main_sizer);
 	this->Layout();
 
 	this->Centre(wxBOTH);

src/slic3r/GUI/PartPlate.cpp

@@ -2298,7 +2298,6 @@ arrangement::ArrangePolygon PartPlate::estimate_wipe_tower_polygon(const Dynamic
 	bool enable_wrapping = (wrapping_opt != nullptr) && wrapping_opt->value;
 	wt_size = estimate_wipe_tower_size(config, w, v, extruder_count, plate_extruder_size, use_global_objects, enable_wrapping);
 	int plate_width=m_width, plate_depth=m_depth;
-	w = wt_size(0); // effective width; differs from prime_tower_width when the rib wall squares the tower
 	float depth = wt_size(1);
 	float margin = WIPE_TOWER_MARGIN + tower_brim_width, wp_brim_width = 0.f;
 	const ConfigOption* wipe_tower_brim_width_opt = config.option("prime_tower_brim_width");

src/slic3r/GUI/PartSkipDialog.cpp

@@ -270,7 +270,7 @@ PartSkipDialog::PartSkipDialog(wxWindow *parent) : DPIDialog(parent, wxID_ANY, _
     m_simplebook->AddPage(m_book_third_panel, _("dialog page"), false);
     m_sizer->Add(m_simplebook, 1, wxEXPAND | wxALL, 5);
 
-    SetSizer(m_sizer);
+    SetSizerAndFit(m_sizer);
     m_zoom_in_btn->Bind(wxEVT_BUTTON, &PartSkipDialog::OnZoomIn, this);
     m_zoom_out_btn->Bind(wxEVT_BUTTON, &PartSkipDialog::OnZoomOut, this);
     m_switch_drag_btn->Bind(wxEVT_BUTTON, &PartSkipDialog::OnSwitchDrag, this);
@@ -281,7 +281,6 @@ PartSkipDialog::PartSkipDialog(wxWindow *parent) : DPIDialog(parent, wxID_ANY, _
     m_all_checkbox->Bind(wxEVT_TOGGLEBUTTON, &PartSkipDialog::OnAllCheckbox, this);
 
     Layout();
-    Fit();
     CentreOnParent();
 }
 

src/slic3r/GUI/Plater.cpp

@@ -14183,7 +14183,7 @@ void Plater::calib_temp(const Calib_Params& params) {
         }
     }
 
-    if (std::abs(nozzle_scale - 1.0) > EPSILON)
+    if (params.nozzle_based_resize && std::abs(nozzle_scale - 1.0) > EPSILON)
         model().objects[0]->scale(nozzle_scale, nozzle_scale, nozzle_scale);
 
     model().objects[0]->ensure_on_bed();
@@ -14191,7 +14191,9 @@ void Plater::calib_temp(const Calib_Params& params) {
     printer_config->set_key_value("resonance_avoidance", new ConfigOptionBool{false});
     set_config_values<int, ConfigOptionInts>(filament_config, "nozzle_temperature_initial_layer", (int) start_temp);
     set_config_values<int, ConfigOptionInts>(filament_config, "nozzle_temperature", (int) start_temp);
-    model().objects[0]->config.set_key_value("layer_height", new ConfigOptionFloat(nozzle_diameter/2));
+    // When resizing is disabled the 0.4 mm / 0.2 mm reference model is printed as-is (preset layer height kept).
+    if (params.nozzle_based_resize)
+        model().objects[0]->config.set_key_value("layer_height", new ConfigOptionFloat(nozzle_diameter/2));
     model().objects[0]->config.set_key_value("brim_type", new ConfigOptionEnum<BrimType>(btOuterOnly));
     model().objects[0]->config.set_key_value("brim_width", new ConfigOptionFloat(5.0));
     model().objects[0]->config.set_key_value("brim_object_gap", new ConfigOptionFloat(0.0));
@@ -14202,7 +14204,8 @@ void Plater::calib_temp(const Calib_Params& params) {
 
     auto print_config = &wxGetApp().preset_bundle->prints.get_edited_preset().config;
     print_config->set_key_value("enable_wrapping_detection", new ConfigOptionBool(false));
-    print_config->set_key_value("initial_layer_print_height", new ConfigOptionFloat(nozzle_diameter/2));
+    if (params.nozzle_based_resize)
+        print_config->set_key_value("initial_layer_print_height", new ConfigOptionFloat(nozzle_diameter/2));
 
 
     changed_objects({ 0 });
@@ -14366,6 +14369,42 @@ void Plater::calib_VFA(const Calib_Params& params)
     auto print_config = &wxGetApp().preset_bundle->prints.get_edited_preset().config;
     auto filament_config = &wxGetApp().preset_bundle->filaments.get_edited_preset().config;
     auto printer_config  = &wxGetApp().preset_bundle->printers.get_edited_preset().config;
+
+    const ConfigOptionFloats* nozzle_diameter_config = printer_config->option<ConfigOptionFloats>("nozzle_diameter");
+    size_t nozzle_id = static_cast<size_t>(std::max(params.extruder_id, 0));
+    double nozzle_diameter = vfa_base_nozzle_diameter;
+    if (nozzle_diameter_config && !nozzle_diameter_config->values.empty()) {
+        nozzle_id = std::min(nozzle_id, nozzle_diameter_config->values.size() - 1);
+        nozzle_diameter = nozzle_diameter_config->values[nozzle_id];
+    }
+    if (nozzle_diameter <= 0.0)
+        nozzle_diameter = vfa_base_nozzle_diameter;
+
+    // Resolved layer height: use the (possibly auto-adjusted) value from the dialog, else default to nozzle/2.
+    double layer_height = params.vfa_layer_height > 0.0 ? params.vfa_layer_height : nozzle_diameter / 2.0;
+
+    // cut upper (on the unscaled model, using the base block height); the scaling below keeps the physical
+    // block height (vfa_layers_per_block * layer_height) in sync with the speed stepping in GCode::process_layer.
+    // Subtract EPSILON (as the temperature tower does) so the cut lands just below the flat block surface instead
+    // of exactly on it, which would otherwise add a degenerate extra layer.
+    auto obj_bb = model().objects[0]->bounding_box_exact();
+    auto height = vfa_base_block_height * ((params.end - params.start) / params.step + 1) - EPSILON;
+    if (height < obj_bb.size().z()) {
+        cut_horizontal(0, 0, height, ModelObjectCutAttribute::KeepLower);
+    }
+
+    // When resizing is enabled, XY scales with the nozzle (footprint / line width) and Z scales so each base
+    // block becomes vfa_layers_per_block layers of the resolved layer height. When disabled the 0.4 mm / 0.2 mm
+    // reference model is printed as-is (preset layer height kept).
+    if (params.nozzle_based_resize) {
+        const double xy_scale = nozzle_diameter / vfa_base_nozzle_diameter;
+        const double z_scale  = (vfa_layers_per_block * layer_height) / vfa_base_block_height;
+        if (std::abs(xy_scale - 1.0) > EPSILON || std::abs(z_scale - 1.0) > EPSILON)
+            model().objects[0]->scale(xy_scale, xy_scale, z_scale);
+    }
+
+    model().objects[0]->ensure_on_bed();
+
     printer_config->set_key_value("resonance_avoidance", new ConfigOptionBool{false});
     filament_config->set_key_value("slow_down_layer_time", new ConfigOptionFloats { 0.0 });
     set_config_values<bool, ConfigOptionBoolsNullable>(print_config, "enable_overhang_speed", false);
@@ -14379,6 +14418,10 @@ void Plater::calib_VFA(const Calib_Params& params)
     print_config->set_key_value("spiral_mode", new ConfigOptionBool(true));
     print_config->set_key_value("enable_wrapping_detection", new ConfigOptionBool(false));
     print_config->set_key_value("precise_z_height", new ConfigOptionBool(false));
+    if (params.nozzle_based_resize) {
+        print_config->set_key_value("initial_layer_print_height", new ConfigOptionFloat(layer_height));
+        model().objects[0]->config.set_key_value("layer_height", new ConfigOptionFloat(layer_height));
+    }
     model().objects[0]->config.set_key_value("brim_type", new ConfigOptionEnum<BrimType>(btOuterOnly));
     model().objects[0]->config.set_key_value("brim_width", new ConfigOptionFloat(3.0));
     model().objects[0]->config.set_key_value("brim_object_gap", new ConfigOptionFloat(0.0));
@@ -14389,14 +14432,11 @@ void Plater::calib_VFA(const Calib_Params& params)
     wxGetApp().get_tab(Preset::TYPE_PRINT)->update_ui_from_settings();
     wxGetApp().get_tab(Preset::TYPE_FILAMENT)->update_ui_from_settings();
 
-    // cut upper
-    auto obj_bb = model().objects[0]->bounding_box_exact();
-    auto height = 5 * ((params.end - params.start) / params.step + 1);
-    if (height < obj_bb.size().z()) {
-        cut_horizontal(0, 0, height, ModelObjectCutAttribute::KeepLower);
-    }
-
-    p->background_process.fff_print()->set_calib_params(params);
+    // Pass the resolved layer height on (only meaningful when resized). GCode's VFA stepping is layer-based, so
+    // it does not require it, but keep it consistent with the geometry.
+    Calib_Params calib_params = params;
+    calib_params.vfa_layer_height = params.nozzle_based_resize ? layer_height : 0.0;
+    p->background_process.fff_print()->set_calib_params(calib_params);
 }
 
 void Plater::calib_input_shaping_freq(const Calib_Params& params)
@@ -15094,7 +15134,7 @@ ProjectDropDialog::ProjectDropDialog(const std::string &filename)
 
     m_sizer_main->Add(dlg_btns, 0, wxEXPAND);
 
-    SetSizer(m_sizer_main);
+    SetSizerAndFit(m_sizer_main);
     Layout();
     Fit();
     Centre(wxBOTH);

src/slic3r/GUI/Preferences.cpp

@@ -1785,6 +1785,9 @@ void PreferencesDialog::create_items()
     auto reverse_mouse_zoom    = create_item_checkbox(_L("Reverse mouse zoom"), _L("If enabled, reverses the direction of zoom with mouse wheel."), "reverse_mouse_wheel_zoom");
     g_sizer->Add(reverse_mouse_zoom);
 
+    auto item_infinite_camera_drag = create_item_checkbox(_L("Infinite camera drag"), _L("If enabled, the mouse pointer is teleported to the opposite side of the 3D view when it reaches a border while panning or orbiting, so camera movement is not limited by the window bounds."), "infinite_camera_drag");
+    g_sizer->Add(item_infinite_camera_drag);
+
     std::vector<wxString> ButtonDragActions = {_L("None"), _L("Pan"), _L("Rotate")};
     auto item_left_mouse_drag  = create_item_combobox(_L("Left Mouse Drag"), _L("Set the action that dragging the left mouse button should perform."), "left_mouse_drag_action", ButtonDragActions);
     g_sizer->Add(item_left_mouse_drag);

src/slic3r/GUI/PrintOptionsDialog.cpp

@@ -28,7 +28,7 @@ PrintOptionsDialog::PrintOptionsDialog(wxWindow* parent)
 {
     this->SetDoubleBuffered(true);
     SetBackgroundColour(*wxWHITE);
-    SetSize(FromDIP(480),FromDIP(520));
+    // SetMinSize(FromDIP(wxSize{wxDefaultCoord,520}));
 
 
     m_scrollwindow = new wxScrolledWindow(this, wxID_ANY);
@@ -50,7 +50,8 @@ PrintOptionsDialog::PrintOptionsDialog(wxWindow* parent)
     m_scrollwindow->FitInside();
 
     this->Layout();
-    // mainSizer->Fit(this);
+    mainSizer->SetMinSize(wxDefaultCoord, FromDIP(520));
+    mainSizer->Fit(this);
     //this->Fit();
 
      m_cb_ai_monitoring->Bind(wxEVT_TOGGLEBUTTON, [this](wxCommandEvent &evt) {
@@ -1670,12 +1671,9 @@ PrinterPartsDialog::PrinterPartsDialog(wxWindow* parent)
     /*inset data*/
     sizer->Add(single_panel, 0, wxEXPAND, 0);
     sizer->Add(multiple_panel, 0, wxEXPAND, 0);
-    SetSizer(sizer);
-    Layout();
-    Fit();
-
     single_panel->Hide();
-
+    SetSizerAndFit(sizer);
+    Layout();
     wxGetApp().UpdateDlgDarkUI(this);
 }
 
@@ -1752,6 +1750,7 @@ bool PrinterPartsDialog::Show(bool show)
             }
         }
 
+        GetSizer()->SetSizeHints(this);
         Layout();
         Fit();
     }

src/slic3r/GUI/PublishDialog.cpp

@@ -119,7 +119,7 @@ PublishDialog::PublishDialog(Plater *plater)
     top_sizer->Add(m_main_sizer, 1, wxALL | wxEXPAND, 0);
     top_sizer->Add(FromDIP(30), 0, 0, wxEXPAND, 0);
 
-    this->SetSizer(top_sizer);
+    this->SetSizerAndFit(top_sizer);
     this->Layout();
 
     this->Centre(wxBOTH);

src/slic3r/GUI/StepMeshDialog.cpp

@@ -310,10 +310,9 @@ StepMeshDialog::StepMeshDialog(wxWindow* parent, Slic3r::Step& file, double line
 
     bSizer->Add(bSizer_button, 1, wxEXPAND);
 
-    this->SetSizer(bSizer);
+    this->SetSizerAndFit(bSizer);
     update_mesh_number_text();
     this->Layout();
-    bSizer->Fit(this);
 
     this->Bind(wxEVT_LEFT_DOWN, [this](auto& e) {
         SetFocusIgnoringChildren();

src/slic3r/GUI/TroubleshootDialog.cpp

@@ -354,7 +354,7 @@ TroubleshootDialog::TroubleshootDialog()
     m_sizer->AddSpacer(FromDIP(20));
     m_sizer->Add(right_sizer, 0, wxEXPAND | wxTOP | wxBOTTOM | wxRIGHT, FromDIP(15));
 
-    SetSizer(m_sizer);
+    SetSizerAndFit(m_sizer);
     Layout();
     Fit();
     CenterOnParent();

src/slic3r/GUI/TroubleshootDialog.hpp

@@ -168,6 +168,9 @@ private:
         }
         wxClientDC dc(this);
         int cWidth = GetClientSize().GetWidth();
+        // Don't compute/commit a size based on a not-yet-laid-out width
+        // Mirrors the guard in OnPaint() so both use the same wrap results
+        if (cWidth < 50) return;
 
         int y = 0;
         for (size_t i = 0; i < m_lines.size(); ++i) {

src/slic3r/GUI/UnsavedChangesDialog.cpp

@@ -773,7 +773,7 @@ std::vector<std::string> DiffViewCtrl::selected_options()
 
 static std::string none{"none"};
 #define UNSAVE_CHANGE_DIALOG_SCROLL_WINDOW_SIZE wxSize(FromDIP(490), FromDIP(374))
-#define UNSAVE_CHANGE_DIALOG_ACTION_LINE_SIZE wxSize(FromDIP(490), FromDIP(60))
+#define UNSAVE_CHANGE_DIALOG_ACTION_LINE_SIZE wxSize(FromDIP(490), -1)
 #define UNSAVE_CHANGE_DIALOG_FIRST_VALUE_WIDTH FromDIP(190)
 #define UNSAVE_CHANGE_DIALOG_VALUE_WIDTH FromDIP(150)
 #define UNSAVE_CHANGE_DIALOG_ITEM_HEIGHT FromDIP(24)
@@ -1075,11 +1075,6 @@ void UnsavedChangesDialog::build(Preset::Type type, PresetCollection *dependent_
     m_sizer_main->Add(m_sizer_button, 0, wxEXPAND | wxTOP, 6);
     m_sizer_main->Add(0, 0, 1, wxTOP, 18);
 
-    SetSizer(m_sizer_main);
-    Layout();
-    Fit();
-    Centre(wxBOTH);
-
     if (params) {
         if (params->left_to_right)
             update_tree(type, params->config, params->from, params->to);
@@ -1095,6 +1090,11 @@ void UnsavedChangesDialog::build(Preset::Type type, PresetCollection *dependent_
     //topSizer->SetSizeHints(this);
 
     show_info_line(Action::Undef);
+
+    SetSizerAndFit(m_sizer_main);
+    Layout();
+    Fit();
+    // Centre(wxBOTH);
 }
 
 void UnsavedChangesDialog::show_info_line(Action action, std::string preset_name)
@@ -1499,6 +1499,7 @@ void UnsavedChangesDialog::update(Preset::Type type, PresetCollection* dependent
     }
 
     m_action_line->SetLabel(action_msg);
+    m_action_line->Wrap(UNSAVE_CHANGE_DIALOG_SCROLL_WINDOW_SIZE.x);
 
     update_tree(type, presets);
     update_list();

src/slic3r/GUI/UpdateDialogs.cpp

@@ -213,9 +213,8 @@ MsgUpdateConfig::MsgUpdateConfig(const std::vector<Update> &updates, bool force_
     m_scrollwindw_release_note->Layout();
 
 
-    SetSizer(m_sizer_main);
+    SetSizerAndFit(m_sizer_main);
     Layout();
-    m_sizer_main->Fit(this);
 
     Centre(wxBOTH);
 	wxGetApp().UpdateDlgDarkUI(this);

src/slic3r/GUI/calib_dlg.cpp

@@ -8,7 +8,9 @@
 #include "Widgets/HyperLink.hpp"
 #include <string>
 #include <vector>
+#include <cmath>
 #include "libslic3r/PrintConfig.hpp"
+#include "libslic3r/Flow.hpp"
 #include "libslic3r/Utils.hpp"
 
 namespace Slic3r { namespace GUI {
@@ -34,6 +36,23 @@ int GetTextMax(wxWindow* parent, const std::vector<wxString>& labels)
     return text_size.x + parent->FromDIP(10);
 }
 
+CheckBox* add_scale_checkbox(wxWindow* parent, wxSizer* settings_sizer)
+{
+    auto row  = new wxBoxSizer(wxHORIZONTAL);
+    auto cb   = new CheckBox(parent);
+    cb->SetValue(true);
+    auto text = new wxStaticText(parent, wxID_ANY, _L("Auto-scale for nozzle"), wxDefaultPosition, wxDefaultSize, wxALIGN_LEFT);
+    cb->SetToolTip(_L("This model is designed around a 0.4 mm nozzle with a 0.2 mm layer height. \n"
+                      "When the scaling option is enabled (recommended), it dynamically resizes to match your current nozzle diameter"
+                      " and an appropriate layer height, making the test both accurate and easy to read.\n"
+                      "Turn scaling off only if you wish to print the reference model exactly as-is."));
+    text->SetToolTip(cb->GetToolTipText());
+    row->Add(cb  , 0, wxALL | wxALIGN_CENTER_VERTICAL, parent->FromDIP(2));
+    row->Add(text, 0, wxALL | wxALIGN_CENTER_VERTICAL, parent->FromDIP(2));
+    settings_sizer->Add(row, 0, wxLEFT | wxTOP, parent->FromDIP(3));
+    return cb;
+}
+
 std::vector<std::string> get_shaper_type_values()
 {
     if (auto* preset_bundle = wxGetApp().preset_bundle) {
@@ -402,6 +421,9 @@ Temp_Calibration_Dlg::Temp_Calibration_Dlg(wxWindow* parent, wxWindowID id, Plat
     temp_step_sizer->Add(m_tiStep      , 0, wxALL | wxALIGN_CENTER_VERTICAL, FromDIP(2));
     settings_sizer->Add(temp_step_sizer, 0, wxLEFT, FromDIP(3));
 
+    // Resize the model to the nozzle diameter (recommended)
+    m_cbResize = add_scale_checkbox(this, settings_sizer);
+
     settings_sizer->AddSpacer(FromDIP(5));
 
     v_sizer->Add(settings_sizer, 0, wxTOP | wxRIGHT | wxLEFT | wxEXPAND, FromDIP(10));
@@ -475,6 +497,7 @@ void Temp_Calibration_Dlg::on_start(wxCommandEvent& event) {
     }
     m_params.start = start;
     m_params.end = end;
+    m_params.nozzle_based_resize = m_cbResize->GetValue();
     m_params.mode = CalibMode::Calib_Temp_Tower;
     m_plater->calib_temp(m_params);
     EndModal(wxID_OK);
@@ -691,6 +714,22 @@ VFA_Test_Dlg::VFA_Test_Dlg(wxWindow* parent, wxWindowID id, Plater* plater)
     vol_step_sizer->Add(m_tiStep     , 0, wxALL | wxALIGN_CENTER_VERTICAL, FromDIP(2));
     settings_sizer->Add(vol_step_sizer, 0, wxLEFT, FromDIP(3));
 
+    // Resize the model to the nozzle diameter (recommended)
+    m_cbResize = add_scale_checkbox(this, settings_sizer);
+
+    // Auto-adjust parameters to the filament's max volumetric speed
+    auto auto_adjust_sizer = new wxBoxSizer(wxHORIZONTAL);
+    m_cbAutoAdjust = new CheckBox(this);
+    m_cbAutoAdjust->SetValue(true);
+    auto auto_adjust_text = new wxStaticText(this, wxID_ANY, _L("Auto-adjust to max volumetric speed"), wxDefaultPosition, wxDefaultSize, wxALIGN_LEFT);
+    m_cbAutoAdjust->SetToolTip(_L("If the end speed would exceed the filament's maximum volumetric speed, automatically lower the layer "
+                                  "height (keeping standard values and staying within the machine's limits) to reach it. If even the "
+                                  "minimum layer height is not enough, lower the end speed instead."));
+    auto_adjust_text->SetToolTip(m_cbAutoAdjust->GetToolTipText());
+    auto_adjust_sizer->Add(m_cbAutoAdjust  , 0, wxALL | wxALIGN_CENTER_VERTICAL, FromDIP(2));
+    auto_adjust_sizer->Add(auto_adjust_text, 0, wxALL | wxALIGN_CENTER_VERTICAL, FromDIP(2));
+    settings_sizer->Add(auto_adjust_sizer, 0, wxLEFT | wxTOP, FromDIP(3));
+
     settings_sizer->AddSpacer(FromDIP(5));
 
     v_sizer->Add(settings_sizer, 0, wxTOP | wxRIGHT | wxLEFT | wxEXPAND, FromDIP(10));
@@ -732,6 +771,136 @@ void VFA_Test_Dlg::on_start(wxCommandEvent& event)
         return;
     }
 
+    // If the requested end speed would exceed the filament's maximum volumetric speed, the slicer clamps the
+    // outer wall speed, so the upper blocks of the tower would all print at the same (clamped) speed instead of
+    // the requested one. Depending on the "Auto-adjust" option, either fix it automatically or just warn.
+    m_params.vfa_layer_height    = 0.0; // 0 = auto (nozzle/2); overridden below when auto-adjusting
+    m_params.nozzle_based_resize = m_cbResize->GetValue();
+    if (const auto* preset_bundle = wxGetApp().preset_bundle) {
+        const auto& printer_config  = preset_bundle->printers.get_edited_preset().config;
+        const auto& print_config    = preset_bundle->prints.get_edited_preset().config;
+        const auto& filament_config = preset_bundle->filaments.get_edited_preset().config;
+
+        const int extruder_id = std::max(m_params.extruder_id, 0);
+        auto get_at = [extruder_id](const ConfigOptionFloats* opt, double fallback) {
+            if (opt == nullptr || opt->values.empty())
+                return fallback;
+            return opt->values[std::min(static_cast<size_t>(extruder_id), opt->values.size() - 1)];
+        };
+
+        const double nozzle_diameter = get_at(printer_config.option<ConfigOptionFloats>("nozzle_diameter"), vfa_base_nozzle_diameter);
+        double preset_lh = nozzle_diameter / 2.0;
+        if (const auto* lh_opt = print_config.option<ConfigOptionFloat>("layer_height"))
+            if (lh_opt->value > 0.0)
+                preset_lh = lh_opt->value;
+        // Layer height the tower will actually print at: nozzle/2 when resizing, else the preset value.
+        const double default_lh      = m_params.nozzle_based_resize ? nozzle_diameter / 2.0 : preset_lh;
+        const double max_vol_speed   = get_at(filament_config.option<ConfigOptionFloats>("filament_max_volumetric_speed"), 0.0);
+        const double machine_min_lh  = get_at(printer_config.option<ConfigOptionFloats>("min_layer_height"), 0.0);
+        const double machine_max_lh  = get_at(printer_config.option<ConfigOptionFloats>("max_layer_height"), 0.0);
+
+        double line_width = print_config.get_abs_value("outer_wall_line_width", nozzle_diameter);
+        if (line_width <= 0.0)
+            line_width = print_config.get_abs_value("line_width", nozzle_diameter);
+        if (line_width <= 0.0)
+            line_width = nozzle_diameter;
+
+        // Max outer-wall speed printable at a given layer height without exceeding the volumetric limit.
+        auto speed_limit_for_lh = [&](double lh) -> double {
+            const double mm3_per_mm = Flow(line_width, lh, nozzle_diameter).mm3_per_mm();
+            return mm3_per_mm > 0.0 ? max_vol_speed / mm3_per_mm : 1e9;
+        };
+
+        auto confirm_clamp = [&](const wxString& question) -> bool {
+            MessageDialog msg_dlg(nullptr,
+                wxString::Format(_L("The end speed (%.0f mm/s) exceeds the filament's maximum volumetric speed "
+                                    "(%.1f mm³/s), which limits the outer wall to about %.0f mm/s at this line width and "
+                                    "layer height.\n Speeds above this will be clamped, so the upper blocks of the tower "
+                                    "will not print at the requested speed.\n\n%s"),
+                                 m_params.end, max_vol_speed, speed_limit_for_lh(default_lh), question),
+                _L("VFA test"), wxICON_WARNING | wxYES_NO | wxNO_DEFAULT);
+            return msg_dlg.ShowModal() == wxID_YES;
+        };
+
+        if (max_vol_speed > 0.0 && nozzle_diameter > 0.0 && m_params.end > speed_limit_for_lh(default_lh)) {
+            // The layer-height auto-adjust only applies when resizing is enabled (it changes the layer height).
+            if (m_cbAutoAdjust->GetValue() && m_params.nozzle_based_resize) {
+                // Candidate layer heights are the ones actually used by the process profiles compatible with the
+                // current printer (clamped to the machine's layer-height limits, when set). A smaller layer height
+                // means a smaller cross-section, hence a higher printable speed under the volumetric limit; pick the
+                // largest candidate that still reaches the end speed to keep the change from the default minimal.
+                std::vector<double> candidates;
+                for (const auto& preset : preset_bundle->prints.get_presets()) {
+                    if (!preset.is_compatible || preset.is_default)
+                        continue;
+                    const auto* lh_opt = preset.config.option<ConfigOptionFloat>("layer_height");
+                    if (lh_opt == nullptr || lh_opt->value <= 0.0)
+                        continue;
+                    const double lh = lh_opt->value;
+                    if ((machine_min_lh > 0.0 && lh < machine_min_lh - 1e-6) ||
+                        (machine_max_lh > 0.0 && lh > machine_max_lh + 1e-6))
+                        continue;
+                    candidates.push_back(lh);
+                }
+                std::sort(candidates.begin(), candidates.end());
+                candidates.erase(std::unique(candidates.begin(), candidates.end(),
+                                             [](double a, double b) { return std::abs(a - b) < 1e-6; }),
+                                 candidates.end());
+
+                // Largest candidate <= the default layer height that still reaches the end speed (smallest change).
+                double chosen_lh = 0.0;
+                for (auto it = candidates.rbegin(); it != candidates.rend(); ++it) {
+                    if (*it > default_lh + 1e-6)
+                        continue; // never increase the layer height above the default
+                    if (speed_limit_for_lh(*it) >= m_params.end) { chosen_lh = *it; break; }
+                }
+
+                if (chosen_lh > 0.0) {
+                    // Reducing the layer height is enough to reach the requested end speed.
+                    m_params.vfa_layer_height = chosen_lh;
+                    MessageDialog msg_dlg(nullptr,
+                        wxString::Format(_L("The end speed (%.0f mm/s) exceeds the filament's maximum volumetric speed "
+                                            "(%.1f mm³/s) at the default layer height (%.2f mm).\n\n"
+                                            "The layer height has been reduced to %.2f mm (a value used by this printer's "
+                                            "profiles) so the tower can reach the requested speed."),
+                                         m_params.end, max_vol_speed, default_lh, chosen_lh),
+                        _L("VFA test"), wxICON_INFORMATION | wxOK);
+                    msg_dlg.ShowModal();
+                } else if (!candidates.empty()) {
+                    // Even the smallest available layer height cannot reach the end speed; propose a lower end speed
+                    // based on that layer height, the line width and the maximum volumetric speed.
+                    const double min_lh    = candidates.front();
+                    const double reachable = speed_limit_for_lh(min_lh);
+                    double new_end = std::floor(reachable / m_params.step) * m_params.step; // snap down to a step multiple
+                    if (new_end < m_params.start + m_params.step)
+                        new_end = m_params.start + m_params.step;
+                    MessageDialog msg_dlg(nullptr,
+                        wxString::Format(_L("Even at the smallest layer height used by this printer's profiles (%.2f mm) the "
+                                            "end speed (%.0f mm/s) exceeds the filament's maximum volumetric speed "
+                                            "(%.1f mm³/s).\n\n"
+                                            "The layer height will be set to %.2f mm and the end speed lowered to %.0f mm/s.\n\n"
+                                            "Continue?"),
+                                         min_lh, m_params.end, max_vol_speed, min_lh, new_end),
+                        _L("VFA test"), wxICON_WARNING | wxYES_NO | wxNO_DEFAULT);
+                    if (msg_dlg.ShowModal() != wxID_YES)
+                        return;
+                    m_params.end              = new_end;
+                    m_params.vfa_layer_height = min_lh;
+                } else {
+                    // No compatible process profiles to draw layer heights from: warn and let the user decide.
+                    if (!confirm_clamp(_L("Continue anyway?")))
+                        return;
+                }
+            } else {
+                // Auto-adjust off, or resizing disabled (which forbids changing the layer height): just warn.
+                if (!confirm_clamp(m_params.nozzle_based_resize
+                        ? _L("Enable \"Auto-adjust\" to fix this automatically, or continue anyway?")
+                        : _L("Enable \"Auto-scale for nozzle\" and \"Auto-adjust\" to fix this automatically, or continue anyway?")))
+                    return;
+            }
+        }
+    }
+
     m_params.mode = CalibMode::Calib_VFA_Tower;
     m_plater->calib_VFA(m_params);
     EndModal(wxID_OK);

src/slic3r/GUI/calib_dlg.hpp

@@ -65,6 +65,7 @@ protected:
     TextInput* m_tiStart;
     TextInput* m_tiEnd;
     TextInput* m_tiStep;
+    CheckBox*  m_cbResize;
     Plater* m_plater;
 };
 
@@ -99,6 +100,8 @@ protected:
     TextInput* m_tiStart;
     TextInput* m_tiEnd;
     TextInput* m_tiStep;
+    CheckBox*  m_cbAutoAdjust;
+    CheckBox*  m_cbResize;
     Plater* m_plater;
 };
 

src/slic3r/Utils/Bonjour.cpp

@@ -871,7 +871,7 @@ void Bonjour::priv::lookup_perform()
 
 	std::vector<LookupSocket*> sockets;
 
-	// resolve intefaces - from PR#6646
+	// resolve interfaces - from PR#6646
 	std::vector<boost::asio::ip::address> interfaces;
 	asio::ip::udp::resolver resolver(*io_service);
 	boost::system::error_code ec;

src/slic3r/Utils/CalibUtils.cpp

@@ -1265,6 +1265,19 @@ void CalibUtils::calib_VFA(const CalibInfo &calib_info, wxString &error_message)
     DynamicPrintConfig filament_config = calib_info.filament_prest->config;
     DynamicPrintConfig printer_config  = calib_info.printer_prest->config;
 
+    const ConfigOptionFloats* nozzle_diameter_config = printer_config.option<ConfigOptionFloats>("nozzle_diameter");
+    size_t nozzle_id = static_cast<size_t>(std::max(params.extruder_id, 0));
+    double nozzle_diameter = vfa_base_nozzle_diameter;
+    if (nozzle_diameter_config && !nozzle_diameter_config->values.empty()) {
+        nozzle_id = std::min(nozzle_id, nozzle_diameter_config->values.size() - 1);
+        nozzle_diameter = nozzle_diameter_config->values[nozzle_id];
+    }
+    if (nozzle_diameter <= 0.0)
+        nozzle_diameter = vfa_base_nozzle_diameter;
+
+    // Resolved layer height: use the (possibly auto-adjusted) value if provided, else default to nozzle/2.
+    double layer_height = params.vfa_layer_height > 0.0 ? params.vfa_layer_height : nozzle_diameter / 2.0;
+
     filament_config.set_key_value("slow_down_layer_time", new ConfigOptionInts{0});
     filament_config.set_key_value("filament_max_volumetric_speed", new ConfigOptionFloats{200});
     filament_config.set_key_value("curr_bed_type", new ConfigOptionEnum<BedType>(calib_info.bed_type));
@@ -1280,13 +1293,18 @@ void CalibUtils::calib_VFA(const CalibInfo &calib_info, wxString &error_message)
     print_config.set_key_value("sparse_infill_density", new ConfigOptionPercent(0));
     print_config.set_key_value("overhang_reverse", new ConfigOptionBool(false));
     print_config.set_key_value("spiral_mode", new ConfigOptionBool(true));
+    print_config.set_key_value("initial_layer_print_height", new ConfigOptionFloat(layer_height));
+    model.objects[0]->config.set_key_value("layer_height", new ConfigOptionFloat(layer_height));
     model.objects[0]->config.set_key_value("brim_type", new ConfigOptionEnum<BrimType>(btOuterOnly));
     model.objects[0]->config.set_key_value("brim_width", new ConfigOptionFloat(3.0));
     model.objects[0]->config.set_key_value("brim_object_gap", new ConfigOptionFloat(0.0));
 
-    // cut upper
+    // cut upper (on the unscaled model, using the base block height); the scaling below keeps the physical
+    // block height (vfa_layers_per_block * layer_height) in sync with the speed stepping in GCode::process_layer.
+    // Subtract EPSILON (as the temperature tower does) so the cut lands just below the flat block surface instead
+    // of exactly on it, which would otherwise add a degenerate extra layer.
     auto obj_bb = model.objects[0]->bounding_box_exact();
-    auto height = 5 * ((params.end - params.start) / params.step + 1);
+    auto height = vfa_base_block_height * ((params.end - params.start) / params.step + 1) - EPSILON;
     if (height < obj_bb.size().z()) {
         cut_model(model, height, ModelObjectCutAttribute::KeepLower);
     }
@@ -1295,6 +1313,13 @@ void CalibUtils::calib_VFA(const CalibInfo &calib_info, wxString &error_message)
         return;
     }
 
+    // XY scales with the nozzle; Z scales so each base block becomes vfa_layers_per_block layers of layer_height.
+    const double xy_scale = nozzle_diameter / vfa_base_nozzle_diameter;
+    const double z_scale  = (vfa_layers_per_block * layer_height) / vfa_base_block_height;
+    if (std::abs(xy_scale - 1.0) > EPSILON || std::abs(z_scale - 1.0) > EPSILON)
+        model.objects[0]->scale(xy_scale, xy_scale, z_scale);
+    model.objects[0]->ensure_on_bed();
+
     DynamicPrintConfig full_config;
     full_config.apply(FullPrintConfig::defaults());
     full_config.apply(print_config);
@@ -1303,7 +1328,10 @@ void CalibUtils::calib_VFA(const CalibInfo &calib_info, wxString &error_message)
 
     init_multi_extruder_params_for_cali(full_config, calib_info);
 
-    process_and_store_3mf(&model, full_config, params, error_message);
+    // Pass the resolved layer height on so the GCode speed stepping matches the geometry.
+    Calib_Params store_params = params;
+    store_params.vfa_layer_height = layer_height;
+    process_and_store_3mf(&model, full_config, store_params, error_message);
     if (!error_message.empty())
         return;
 

tests/fff_print/test_skirt_brim.cpp

@@ -153,6 +153,24 @@ TEST_CASE("Object brims are generated per instance", "[SkirtBrim]")
     }
 }
 
+TEST_CASE("Uncombined neighboring brims precede their respective objects", "[SkirtBrim]")
+{
+    Print print;
+    Model model;
+    place_two_cubes_apart(0, {
+        { "skirt_loops",   0 },
+        { "brim_type",     "outer_only" },
+        { "brim_width",    5 },
+        { "combine_brims", 0 },
+    }, print, model);
+    print.process();
+
+    REQUIRE(print.skirt_brim_groups().size() == 1);
+    REQUIRE(print.skirt_brim_groups().front().brims.size() == 2);
+    CHECK(role_sequence(gcode(print), { "brim", "perimeter" }) ==
+          std::vector<std::string>{ "brim", "perimeter", "brim", "perimeter" });
+}
+
 TEST_CASE("Combine brims merges neighboring object instances", "[SkirtBrim]")
 {
     Print print;

tests/libslic3r/CMakeLists.txt

@@ -32,6 +32,7 @@ add_executable(${_TEST_NAME}_tests
     test_timeutils.cpp
     test_voronoi.cpp
     test_optimizers.cpp
+    test_ordering_strategies.cpp
     # test_png_io.cpp
     test_indexed_triangle_set.cpp
     ../libnest2d/printer_parts.cpp

tests/libslic3r/test_config_variant_expansion.cpp

@@ -43,33 +43,18 @@ TEST_CASE("apply_override fills nil entries from the 0-based default index", "[C
         REQUIRE(resolved.values == std::vector<double>({30., 42.}));
     }
 
-    SECTION("an index past the machine slots keeps the slot's own value") {
+    SECTION("an index past the machine slots falls back to the first slot") {
         std::vector<int> slot_index{5, 0};
         ConfigOptionFloats resolved(machine);
         REQUIRE(resolved.apply_override(&filament, slot_index));
         REQUIRE(resolved.values == std::vector<double>({10., 42.}));
     }
 
-    SECTION("a negative index (unresolved slot) keeps the slot's own value") {
-        ConfigOptionFloatsNullable all_nil;
-        all_nil.values = {ConfigOptionFloatsNullable::nil_value(), ConfigOptionFloatsNullable::nil_value(),
-                          ConfigOptionFloatsNullable::nil_value()};
-        std::vector<int> slot_index{2, -1, 0};
+    SECTION("a negative index (unresolved slot) falls back to the first slot") {
+        std::vector<int> slot_index{-1, 0};
         ConfigOptionFloats resolved(machine);
-        REQUIRE(!resolved.apply_override(&all_nil, slot_index));
-        REQUIRE(resolved.values == std::vector<double>({30., 20., 10.}));
-    }
-
-    SECTION("all-nil overrides keyed by unresolved slots leave the machine values intact") {
-        // The failed-lookup map a degenerate print_extruder_id used to produce; the negative
-        // slots must not collapse the machine array to its first value.
-        ConfigOptionFloats per_extruder({100., 70., 70., 70., 100.});
-        ConfigOptionFloatsNullable all_nil;
-        all_nil.values.assign(5, ConfigOptionFloatsNullable::nil_value());
-        std::vector<int> slot_index{0, -1, -1, -1, 0};
-        ConfigOptionFloats resolved(per_extruder);
-        REQUIRE(!resolved.apply_override(&all_nil, slot_index));
-        REQUIRE(resolved.values == std::vector<double>({100., 70., 70., 70., 100.}));
+        REQUIRE(resolved.apply_override(&filament, slot_index));
+        REQUIRE(resolved.values == std::vector<double>({10., 42.}));
     }
 }
 
@@ -287,102 +272,6 @@ TEST_CASE("update_values_to_printer_extruders expands one slot per (extruder x v
     }
 }
 
-TEST_CASE("update_values_to_printer_extruders synthesizes degenerate process variant columns", "[Config]")
-{
-    // Non-BBL process presets and 3mf project configs keep the length-1 defaults for
-    // print_extruder_id/print_extruder_variant; only BBL system presets ship full-width columns.
-    auto add_degenerate_print_columns = [](DynamicPrintConfig &config) {
-        config.option<ConfigOptionInts>("print_extruder_id", true)->values = {1};
-        config.option<ConfigOptionStrings>("print_extruder_variant", true)->values = {"Direct Drive Standard"};
-        config.option<ConfigOptionFloats>("outer_wall_speed", true)->values = {30.};
-    };
-
-    SECTION("a single-column pair on a multi-extruder machine expands to one column per extruder") {
-        DynamicPrintConfig config;
-        config.option<ConfigOptionEnumsGeneric>("extruder_type", true)->values = {etDirectDrive, etDirectDrive};
-        config.option<ConfigOptionEnumsGeneric>("nozzle_volume_type", true)->values = {nvtStandard, nvtStandard};
-        config.option<ConfigOptionStrings>("extruder_variant_list", true)->values = {"Direct Drive Standard", "Direct Drive Standard"};
-        add_degenerate_print_columns(config);
-
-        std::vector<std::vector<NozzleVolumeType>> nozzle_volume_types;
-        int extruder_count = 2;
-        int count = config.get_extruder_nozzle_volume_count(extruder_count, nozzle_volume_types);
-
-        std::vector<int> variant_index = config.update_values_to_printer_extruders(config, extruder_count, count, nozzle_volume_types,
-            print_options_with_variant, "print_extruder_id", "print_extruder_variant");
-
-        REQUIRE(variant_index == std::vector<int>({0, 1}));
-        REQUIRE(config.option<ConfigOptionInts>("print_extruder_id")->values == std::vector<int>({1, 2}));
-        REQUIRE(config.option<ConfigOptionStrings>("print_extruder_variant")->values ==
-                std::vector<std::string>({"Direct Drive Standard", "Direct Drive Standard"}));
-        // width-1 data arrays replicate their only column into every slot
-        REQUIRE(config.option<ConfigOptionFloats>("outer_wall_speed")->values == std::vector<double>({30., 30.}));
-    }
-
-    SECTION("a multi-variant list synthesizes one column per (extruder x variant)") {
-        DynamicPrintConfig config = make_hybrid_printer_config();
-        add_degenerate_print_columns(config);
-
-        std::vector<std::vector<NozzleVolumeType>> nozzle_volume_types;
-        int extruder_count = 2;
-        int count = config.get_extruder_nozzle_volume_count(extruder_count, nozzle_volume_types);
-        REQUIRE(count == 3);
-
-        std::vector<int> variant_index = config.update_values_to_printer_extruders(config, extruder_count, count, nozzle_volume_types,
-            print_options_with_variant, "print_extruder_id", "print_extruder_variant");
-
-        // same slot resolution as the explicit BBL-style 4-column layout
-        REQUIRE(variant_index == std::vector<int>({0, 2, 3}));
-        REQUIRE(config.option<ConfigOptionInts>("print_extruder_id")->values == std::vector<int>({1, 2, 2}));
-        REQUIRE(config.option<ConfigOptionStrings>("print_extruder_variant")->values ==
-                std::vector<std::string>({"Direct Drive Standard", "Direct Drive Standard", "Direct Drive High Flow"}));
-        REQUIRE(config.option<ConfigOptionFloats>("outer_wall_speed")->values == std::vector<double>({30., 30., 30.}));
-    }
-
-    SECTION("a single-extruder single-column layout is not treated as degenerate") {
-        DynamicPrintConfig config;
-        config.option<ConfigOptionEnumsGeneric>("extruder_type", true)->values = {etDirectDrive};
-        config.option<ConfigOptionEnumsGeneric>("nozzle_volume_type", true)->values = {nvtStandard};
-        config.option<ConfigOptionStrings>("extruder_variant_list", true)->values = {"Direct Drive Standard"};
-        add_degenerate_print_columns(config);
-
-        std::vector<std::vector<NozzleVolumeType>> nozzle_volume_types;
-        int extruder_count = 1;
-        int count = config.get_extruder_nozzle_volume_count(extruder_count, nozzle_volume_types);
-
-        config.update_values_to_printer_extruders(config, extruder_count, count, nozzle_volume_types,
-            print_options_with_variant, "print_extruder_id", "print_extruder_variant");
-
-        REQUIRE(config.option<ConfigOptionInts>("print_extruder_id")->values == std::vector<int>({1}));
-        REQUIRE(config.option<ConfigOptionFloats>("outer_wall_speed")->values == std::vector<double>({30.}));
-    }
-
-    SECTION("a second expansion leaves the synthesized layout unchanged") {
-        DynamicPrintConfig config;
-        config.option<ConfigOptionEnumsGeneric>("extruder_type", true)->values = {etDirectDrive, etDirectDrive};
-        config.option<ConfigOptionEnumsGeneric>("nozzle_volume_type", true)->values = {nvtStandard, nvtStandard};
-        config.option<ConfigOptionStrings>("extruder_variant_list", true)->values = {"Direct Drive Standard", "Direct Drive Standard"};
-        add_degenerate_print_columns(config);
-
-        std::vector<std::vector<NozzleVolumeType>> nozzle_volume_types;
-        int extruder_count = 2;
-        int count = config.get_extruder_nozzle_volume_count(extruder_count, nozzle_volume_types);
-
-        config.update_values_to_printer_extruders(config, extruder_count, count, nozzle_volume_types,
-            print_options_with_variant, "print_extruder_id", "print_extruder_variant");
-        DynamicPrintConfig once = config;
-        config.update_values_to_printer_extruders(config, extruder_count, count, nozzle_volume_types,
-            print_options_with_variant, "print_extruder_id", "print_extruder_variant");
-
-        REQUIRE(config.option<ConfigOptionInts>("print_extruder_id")->values ==
-                once.option<ConfigOptionInts>("print_extruder_id")->values);
-        REQUIRE(config.option<ConfigOptionStrings>("print_extruder_variant")->values ==
-                once.option<ConfigOptionStrings>("print_extruder_variant")->values);
-        REQUIRE(config.option<ConfigOptionFloats>("outer_wall_speed")->values ==
-                once.option<ConfigOptionFloats>("outer_wall_speed")->values);
-    }
-}
-
 TEST_CASE("update_values_to_printer_extruders_for_multiple_filaments resolves per-filament slots", "[Config]")
 {
     auto make_filament_arrays = [](DynamicPrintConfig &config) {

tests/libslic3r/test_ordering_strategies.cpp

@@ -0,0 +1,297 @@
+#include <catch2/catch_all.hpp>
+
+#define SLIC3R_TEST_HARNESS
+
+#include "libslic3r/Point.hpp"
+#include "libslic3r/GCode/OrderingStrategies.hpp"
+#include "libslic3r/Geometry.hpp"
+
+#include <algorithm>
+#include <unordered_set>
+
+using namespace Slic3r;
+
+// --- Helpers ---
+
+static double euclidean_path_length(const std::vector<size_t>& path, const Points& centers)
+{
+    return tsp_cycle_path_length(path, centers);
+}
+
+static bool has_crossings(const std::vector<size_t>& path, const Points& centers)
+{
+    size_t pn = path.size();
+    if (pn < 4) return false;
+    for (size_t i = 0; i < pn; ++i) {
+        size_t i_next = (i + 1) % pn;
+        for (size_t j = i + 2; j < pn; ++j) {
+            if (j == i_next) continue;
+            if (j == (pn - 1) && i == 0) continue;
+            size_t j_next = (j + 1) % pn;
+            if (Geometry::segments_intersect(
+                    centers[path[i]], centers[path[i_next]],
+                    centers[path[j]], centers[path[j_next]])) {
+                return true;
+            }
+        }
+    }
+    return false;
+}
+
+static bool is_permutation(const std::vector<size_t>& path, size_t n)
+{
+    if (path.size() != n) return false;
+    std::unordered_set<size_t> seen(path.begin(), path.end());
+    for (size_t i = 0; i < n; ++i) {
+        if (seen.count(i) != 1) return false;
+    }
+    return true;
+}
+
+// --- Test fixtures ---
+
+static Points make_grid_4x4()
+{
+    Points pts;
+    for (int row = 0; row < 4; ++row)
+        for (int col = 0; col < 4; ++col)
+            pts.emplace_back(100000 * col, 100000 * row);
+    return pts;
+}
+
+static Points make_linear_5()
+{
+    Points pts;
+    for (int i = 0; i < 5; ++i)
+        pts.emplace_back(100000 * i, 0);
+    return pts;
+}
+
+static Points make_ring_8()
+{
+    Points pts;
+    constexpr double R = 100000.0;
+    for (int i = 0; i < 8; ++i) {
+        double angle = 2.0 * M_PI * i / 8.0;
+        pts.emplace_back(static_cast<coord_t>(R * std::cos(angle)),
+                         static_cast<coord_t>(R * std::sin(angle)));
+    }
+    return pts;
+}
+
+static Points make_random_16()
+{
+    // Deterministic "random" points via simple hash.
+    Points pts;
+    for (int i = 0; i < 16; ++i) {
+        uint32_t h = static_cast<uint32_t>(i * 2654435761u);
+        coord_t x = static_cast<coord_t>((h >> 16) & 0xFFFF) * 10;
+        coord_t y = static_cast<coord_t>(h & 0xFFFF) * 10;
+        pts.emplace_back(x, y);
+    }
+    return pts;
+}
+
+// --- TSP Post-Processing Tests ---
+
+TEST_CASE("tsp_2opt_improve reduces path length", "[TSPPostProcessing]") {
+    Points centers = make_random_16();
+    std::vector<size_t> path(centers.size());
+    // Reverse half the path to create a deliberately bad ordering.
+    for (size_t i = 0; i < path.size(); ++i) path[i] = i;
+    std::reverse(path.begin(), path.end() - path.size() / 2);
+
+    double before = euclidean_path_length(path, centers);
+    tsp_2opt_improve(path, centers);
+    double after = euclidean_path_length(path, centers);
+
+    REQUIRE(is_permutation(path, centers.size()));
+    CHECK(after <= before);
+}
+
+TEST_CASE("tsp_remove_crossings eliminates crossings", "[TSPPostProcessing]") {
+    Points centers = make_random_16();
+    std::vector<size_t> path(centers.size());
+    for (size_t i = 0; i < path.size(); ++i) path[i] = i;
+    // Create a crossing by reversing a middle segment.
+    if (path.size() >= 4) {
+        std::reverse(path.begin() + 1, path.end() - 1);
+    }
+
+    tsp_remove_crossings(path, centers);
+    CHECK(!has_crossings(path, centers));
+    REQUIRE(is_permutation(path, centers.size()));
+}
+
+
+
+TEST_CASE("tsp_rotate_minimize_closing shortens closing edge", "[TSPPostProcessing]") {
+    Points centers = make_random_16();
+    std::vector<size_t> path(centers.size());
+    for (size_t i = 0; i < path.size(); ++i) path[i] = i;
+
+    // Compute all possible closing edge lengths.
+    size_t pn = path.size();
+    double min_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 < min_closing2) min_closing2 = d2;
+    }
+
+    tsp_rotate_minimize_closing(path, centers);
+
+    // Closing edge should be the minimum possible.
+    double actual_closing2 = (centers[path.front()].cast<double>() - centers[path.back()].cast<double>()).squaredNorm();
+    CHECK(actual_closing2 == min_closing2);
+    REQUIRE(is_permutation(path, centers.size()));
+}
+
+TEST_CASE("tsp_cycle_path_length is correct for triangle", "[TSPPostProcessing]") {
+    Points pts;
+    pts.emplace_back(0, 0);
+    pts.emplace_back(100000, 0);
+    pts.emplace_back(50000, 86602); // equilateral ~100mm sides
+
+    std::vector<size_t> path = {0, 1, 2};
+    double len = tsp_cycle_path_length(path, pts);
+    // Perimeter of equilateral triangle with side ~100000.
+    REQUIRE(len > 290000);
+    REQUIRE(len < 310000);
+}
+
+TEST_CASE("tsp_max_edge_length finds longest edge", "[TSPPostProcessing]") {
+    Points pts;
+    pts.emplace_back(0, 0);
+    pts.emplace_back(100000, 0);
+    pts.emplace_back(50000, 0);
+
+    std::vector<size_t> path = {0, 1, 2};
+    double mx = tsp_max_edge_length(path, pts);
+    // Longest edge is 0->1 = 100000.
+    CHECK(mx == Catch::Approx(100000).margin(1));
+}
+
+// --- Core Strategy Tests: Empty / Small Inputs ---
+
+TEST_CASE("snake_core handles empty input", "[Snake]") {
+    Points centers;
+    auto path = snake_core(centers);
+    REQUIRE(path.empty());
+}
+
+TEST_CASE("snake_core handles single point", "[Snake]") {
+    Points pts{{100, 200}};
+    CHECK(snake_core(pts) == std::vector<size_t>{0});
+}
+
+TEST_CASE("snake_core handles two points", "[Snake]") {
+    Points pts{{100, 200}, {300, 400}};
+    auto p2 = snake_core(pts);
+
+    REQUIRE(is_permutation(p2, 2));
+}
+
+// --- Core Strategy Tests: Grid Layout ---
+
+TEST_CASE("snake produces good path on grid", "[Snake]") {
+    Points centers = make_grid_4x4();
+    auto path = snake_core(centers);
+
+    REQUIRE(is_permutation(path, centers.size()));
+    CHECK(!has_crossings(path, centers));
+}
+
+// --- Core Strategy Tests: Variable Row Spacing ---
+
+TEST_CASE("snake handles variable Y spacing", "[Snake]") {
+    // Rows at Y = 0, 50, 100, 1000 (large gap between last two rows).
+    // The adaptive row detection should identify the tight cluster (0, 50, 100)
+    // and the isolated row (1000) without splitting them incorrectly.
+    Points pts;
+    pts.emplace_back(0, 0);       pts.emplace_back(100000, 0);
+    pts.emplace_back(0, 50000);   pts.emplace_back(100000, 50000);
+    pts.emplace_back(0, 100000);  pts.emplace_back(100000, 100000);
+    pts.emplace_back(0, 1000000); pts.emplace_back(100000, 1000000);
+
+    auto path = snake_core(pts);
+    REQUIRE(is_permutation(path, pts.size()));
+    CHECK(!has_crossings(path, pts));
+}
+
+// --- Core Strategy Tests: All Points Same Y ---
+
+TEST_CASE("snake handles all points on same Y", "[Snake]") {
+    // All points share the same Y coordinate. This exercises the
+    // division-by-zero guard (ys.size() == 1).
+    Points pts;
+    for (int i = 0; i < 6; ++i)
+        pts.emplace_back(100000 * i, 50000);
+
+    auto path = snake_core(pts);
+    REQUIRE(is_permutation(path, pts.size()));
+}
+
+// --- Core Strategy Tests: Collinear Points ---
+
+TEST_CASE("snake_core handles collinear points", "[Snake]") {
+    Points centers = make_linear_5();
+
+    auto p2 = snake_core(centers);
+
+    REQUIRE(is_permutation(p2, centers.size()));
+}
+
+// --- Core Strategy Tests: Ring Layout ---
+
+TEST_CASE("snake_core produces valid paths on ring", "[Snake]") {
+    Points centers = make_ring_8();
+
+    auto p2 = snake_core(centers);
+
+    REQUIRE(is_permutation(p2, centers.size()));
+}
+
+// --- Core Strategy Tests: Random Layout ---
+
+TEST_CASE("snake_core produces valid paths on random input", "[Snake]") {
+    Points centers = make_random_16();
+
+    auto p2 = snake_core(centers);
+
+    REQUIRE(is_permutation(p2, centers.size()));
+}
+
+// --- Quality Comparison Tests ---
+
+TEST_CASE("snake has no crossings on random input", "[Snake]") {
+    Points centers = make_random_16();
+    auto path = snake_core(centers);
+
+    REQUIRE(is_permutation(path, centers.size()));
+    CHECK(!has_crossings(path, centers));
+}
+
+// --- Edge Cases ---
+
+TEST_CASE("snake_core handles duplicate points", "[Snake]") {
+    Points pts;
+    pts.emplace_back(100, 200);
+    pts.emplace_back(100, 200); // duplicate
+    pts.emplace_back(300, 400);
+
+    auto p2 = snake_core(pts);
+
+    REQUIRE(p2.size() == pts.size());
+}
+
+TEST_CASE("snake_core handles three points", "[Snake]") {
+    Points pts;
+    pts.emplace_back(0, 0);
+    pts.emplace_back(100000, 0);
+    pts.emplace_back(50000, 86602);
+
+    auto p2 = snake_core(pts);
+
+    REQUIRE(is_permutation(p2, 3));
+}

tests/libslic3r/test_toolordering_nozzle_group.cpp

@@ -500,52 +500,6 @@ TEST_CASE("Re-applying an unchanged config after slicing keeps the result valid"
     REQUIRE(print.is_step_done(psSlicingFinished));
 }
 
-TEST_CASE("A degenerate process variant map on a custom multi-extruder printer slices to a stable result", "[Print][Regression]")
-{
-    // Non-BBL multi-extruder printers get machine-scope variant columns synthesized on preset
-    // load (extend_extruder_variant), but nothing ships process-scope print_extruder_id /
-    // print_extruder_variant: presets and 3mf project configs carry the length-1 defaults. The
-    // apply-time expansion must synthesize the process columns from extruder_variant_list;
-    // otherwise the failed per-extruder lookups collapse the per-extruder retract overrides
-    // during slicing and the post-slice re-apply invalidates every fresh result, forever.
-    DynamicPrintConfig config = DynamicPrintConfig::full_print_config();
-    config.option<ConfigOptionFloats>("nozzle_diameter", true)->values = {0.4, 0.4, 0.4, 0.4, 0.4};
-    config.set_num_extruders(5);
-    // per-extruder machine values that a first-slot collapse would destroy
-    config.option<ConfigOptionPercents>("retract_before_wipe", true)->values = {100., 70., 70., 70., 100.};
-    config.option<ConfigOptionEnumsGeneric>("z_hop_types", true)->values = {zhtSlope, zhtNormal, zhtNormal, zhtNormal, zhtSlope};
-    // filament presets carry the nullable override twins (all-nil = "no override"); they are what
-    // routes the machine values through apply_override in the in-slice override recompute
-    config.option<ConfigOptionPercentsNullable>("filament_retract_before_wipe", true)->values =
-        std::vector<double>(5, ConfigOptionPercentsNullable::nil_value());
-    config.option<ConfigOptionEnumsGenericNullable>("filament_z_hop_types", true)->values =
-        std::vector<int>(5, ConfigOptionEnumsGenericNullable::nil_value());
-    config.option<ConfigOptionFloats>("filament_diameter", true)->values = std::vector<double>(5, 1.75);
-    config.option<ConfigOptionStrings>("filament_colour", true)->values = {"#FF0000", "#00FF00", "#0000FF", "#FFFF00", "#00FFFF"};
-    config.option<ConfigOptionInts>("filament_map", true)->values = {1, 2, 3, 4, 1};
-
-    Model model;
-    model.add_object("cube", "", make_cube(20, 20, 20))->add_instance()->set_offset(Vec3d(100., 100., 0.));
-
-    Print print;
-    print.apply(model, config);
-    print.process();
-    REQUIRE(print.is_step_done(psSlicingFinished));
-
-    // BackgroundSlicingProcess reads the engine-computed maps back into the plate config after
-    // slicing; the next apply overlays that written-back state.
-    config.option<ConfigOptionInts>("filament_map", true)->values = print.get_filament_maps();
-    config.option<ConfigOptionInts>("filament_volume_map", true)->values = print.get_filament_volume_maps();
-    config.option<ConfigOptionInts>("filament_nozzle_map", true)->values = print.get_filament_nozzle_maps();
-
-    auto status = print.apply(model, config);
-    REQUIRE(status == PrintBase::APPLY_STATUS_UNCHANGED);
-    REQUIRE(print.is_step_done(psSlicingFinished));
-    // the per-extruder machine values must survive the in-slice override recompute
-    REQUIRE(print.config().retract_before_wipe.values == std::vector<double>({100., 70., 70., 70., 100.}));
-    REQUIRE(print.config().z_hop_types.values == std::vector<int>({zhtSlope, zhtNormal, zhtNormal, zhtNormal, zhtSlope}));
-}
-
 TEST_CASE("normalize_nozzle_map_per_layer makes per-filament assignments gap-free", "[MultiNozzle][H2C][Dynamic]")
 {
     SECTION("gaps inherit the last used nozzle, entries on used layers stay untouched") {