Top Surface Expansion (#14296)

Co-authored-by: Rodrigo Faselli <162915171+RF47@users.noreply.github.com>

src/libslic3r/Clipper2Utils.cpp

@@ -188,6 +188,18 @@ ExPolygons offset_ex_2(const ExPolygons &expolygons, double delta)
     return results;
 }
 
+ExPolygons offset_ex_2(const ExPolygons &expolygons, double delta, Clipper2Lib::JoinType joinType)
+{
+    Clipper2Lib::Paths64 subject = Slic3rExPolygons_to_Paths64(expolygons);
+    Clipper2Lib::ClipperOffset offsetter;
+    offsetter.AddPaths(subject, joinType, Clipper2Lib::EndType::Polygon);
+    Clipper2Lib::PolyPath64 polytree;
+    offsetter.Execute(delta, polytree);
+    ExPolygons results = PolyTreeToExPolygons(std::move(polytree));
+
+    return results;
+}
+
 ExPolygons offset2_ex_2(const ExPolygons& expolygons, double delta1, double delta2)
 {
     // 1st offset

src/libslic3r/Clipper2Utils.hpp

@@ -15,6 +15,7 @@ Slic3r::Polylines  diff_pl_2(const Slic3r::Polylines& subject, const Slic3r::Pol
 ExPolygons         union_ex_2(const Polygons &expolygons);
 ExPolygons         union_ex_2(const ExPolygons &expolygons);
 ExPolygons         offset_ex_2(const ExPolygons &expolygons, double delta);
+ExPolygons         offset_ex_2(const ExPolygons &expolygons, double delta, Clipper2Lib::JoinType joinType);
 ExPolygons         offset2_ex_2(const ExPolygons &expolygons, double delta1, double delta2);
 }
 

src/libslic3r/PerimeterGenerator.cpp

@@ -571,6 +571,19 @@ static ExtrusionEntityCollection traverse_extrusions(const PerimeterGenerator& p
     return extrusion_coll;
 }
 
+// ORCA: only_one_wall_top detects the top as "slice − upper", so a feature rising from the middle of a
+// top surface becomes an enclosed hole that gets ringed with extra inner walls. Fill those holes back
+// into the top. Only holes that are both covered by the upper layer (excludes bridges) and backed by
+// solid material (excludes voids) are filled.
+static ExPolygons fill_enclosed_top_feature_holes(const ExPolygons &top, const Polygons &covered_by_upper, const ExPolygons &solid)
+{
+    ExPolygons filled = top;
+    for (ExPolygon &ex : filled)
+        ex.holes.clear();
+    const ExPolygons feature_holes = intersection_ex(intersection_ex(diff_ex(filled, top), covered_by_upper), solid);
+    return feature_holes.empty() ? top : union_ex(top, feature_holes);
+}
+
 void PerimeterGenerator::split_top_surfaces(const ExPolygons &orig_polygons, ExPolygons &top_fills,
                                             ExPolygons &non_top_polygons, ExPolygons &fill_clip) const {
     // other perimeters
@@ -636,6 +649,8 @@ void PerimeterGenerator::split_top_surfaces(const ExPolygons &orig_polygons, ExP
     ExPolygons delete_bridge = diff_ex(orig_polygons, bridge_checker, ApplySafetyOffset::Yes);
 
     ExPolygons top_polygons = diff_ex(delete_bridge, upper_polygons_series_clipped, ApplySafetyOffset::Yes);
+    top_polygons = fill_enclosed_top_feature_holes(top_polygons, upper_polygons_series_clipped, orig_polygons);
+
     // get the not-top surface, from the "real top" but enlarged by external_infill_margin (and the
     // min_width_top_surface we removed a bit before)
     ExPolygons temp_gap = diff_ex(top_polygons, fill_clip);
@@ -2194,6 +2209,7 @@ void PerimeterGenerator::process_arachne()
                 upper_slices_clipped = ClipperUtils::clip_clipper_polygons_with_subject_bbox(*upper_slices, infill_contour_bbox);
 
             top_expolygons = diff_ex(infill_contour, upper_slices_clipped);
+            top_expolygons = fill_enclosed_top_feature_holes(top_expolygons, upper_slices_clipped, infill_contour);
 
             if (!top_expolygons.empty()) {
                 if (lower_slices != nullptr) {

src/libslic3r/Preset.cpp

@@ -1044,6 +1044,9 @@ static std::vector<std::string> s_Preset_print_options{
     "lightning_prune_angle",
     "lightning_straightening_angle",
     "top_surface_pattern",
+    "top_surface_expansion",
+    "top_surface_expansion_margin",
+    "top_surface_expansion_direction",
     "bottom_surface_pattern",
     "infill_direction",
     "solid_infill_direction",

src/libslic3r/PrintConfig.cpp

@@ -221,6 +221,13 @@ static t_config_enum_values s_keys_map_FuzzySkinMode {
 };
 CONFIG_OPTION_ENUM_DEFINE_STATIC_MAPS(FuzzySkinMode)
 
+static t_config_enum_values s_keys_map_TopSurfaceExpansionDirection {
+    { "inward_and_outward", int(TopSurfaceExpansionDirection::InwardAndOutward) },
+    { "inward",             int(TopSurfaceExpansionDirection::Inward) },
+    { "outward",            int(TopSurfaceExpansionDirection::Outward) }
+};
+CONFIG_OPTION_ENUM_DEFINE_STATIC_MAPS(TopSurfaceExpansionDirection)
+
 static t_config_enum_values s_keys_map_InfillPattern {
     { "monotonic", ipMonotonic },
     { "monotonicline", ipMonotonicLine },
@@ -2123,6 +2130,47 @@ void PrintConfigDef::init_fff_params()
     def->max = 100;
     def->set_default_value(new ConfigOptionPercent(100));
 
+    def = this->add("top_surface_expansion", coFloat);
+    def->label = L("Top surface expansion");
+    def->category = L("Strength");
+    def->tooltip = L("Expands the top surfaces by this distance to connect distinct top surfaces and fill gaps.\n"
+                     "Useful for cases where the top surface is interrupted by a raised feature, such as text on a plane."
+                     "Expanding it removes the holes beneath these features and creates a continuous path with a better finish for printing on top."
+                     "The expansion is applied to the original top surface, before any other processing such as bridging or overhang detection.");
+    def->sidetext = L("mm");
+    def->min = 0;
+    def->mode = comAdvanced;
+    def->set_default_value(new ConfigOptionFloat(0));
+
+    def = this->add("top_surface_expansion_margin", coFloat);
+    def->label = L("Top expansion wall margin");
+    def->category = L("Strength");
+    def->tooltip = L("Using “Top surface expansion” may cause a surface that did not previously touch the model's outer walls to now do so.\n"
+                     "This can cause contraction marks (such as the hull line) on the outer walls.\n"
+                     "By adding a small margin, this contraction will not occur directly on the walls, thereby preventing a visible mark.");
+    def->sidetext = L("mm");
+    def->min = 0;
+    def->max = 10;
+    def->mode = comAdvanced;
+    def->set_default_value(new ConfigOptionFloat(0));
+
+    def = this->add("top_surface_expansion_direction", coEnum);
+    def->label = L("Top expansion direction");
+    def->category = L("Strength");
+    def->tooltip = L("Direction in which the top surface expansion grows.\n"
+                     " - Inward grows into the holes and gaps left by features rising from the middle of a top surface.\n"
+                     " - Outward grows the outer edge of the surface, connecting surfaces separated by features that can divide a surface, such as a lattice pattern.\n"
+                     " - Inward and Outward does both.");
+    def->enum_keys_map = &ConfigOptionEnum<TopSurfaceExpansionDirection>::get_enum_values();
+    def->enum_values.push_back("inward_and_outward");
+    def->enum_values.push_back("inward");
+    def->enum_values.push_back("outward");
+    def->enum_labels.push_back(L("Inward and Outward"));
+    def->enum_labels.push_back(L("Inward"));
+    def->enum_labels.push_back(L("Outward"));
+    def->mode = comAdvanced;
+    def->set_default_value(new ConfigOptionEnum<TopSurfaceExpansionDirection>(TopSurfaceExpansionDirection::InwardAndOutward));
+
     def = this->add("bottom_surface_pattern", coEnum);
     def->label = L("Bottom surface pattern");
     def->category = L("Strength");

src/libslic3r/PrintConfig.hpp

@@ -62,6 +62,13 @@ enum class FuzzySkinMode {
     Combined,
 };
 
+// ORCA: direction in which top_surface_expansion grows the top surfaces.
+enum class TopSurfaceExpansionDirection {
+    InwardAndOutward,
+    Inward,
+    Outward,
+};
+
 enum class NoiseType {
     Classic,
     Perlin,
@@ -540,6 +547,7 @@ CONFIG_OPTION_ENUM_DECLARE_STATIC_MAPS(PrinterTechnology)
 CONFIG_OPTION_ENUM_DECLARE_STATIC_MAPS(GCodeFlavor)
 CONFIG_OPTION_ENUM_DECLARE_STATIC_MAPS(FuzzySkinType)
 CONFIG_OPTION_ENUM_DECLARE_STATIC_MAPS(FuzzySkinMode)
+CONFIG_OPTION_ENUM_DECLARE_STATIC_MAPS(TopSurfaceExpansionDirection)
 CONFIG_OPTION_ENUM_DECLARE_STATIC_MAPS(WipeTowerType)
 CONFIG_OPTION_ENUM_DECLARE_STATIC_MAPS(NoiseType)
 CONFIG_OPTION_ENUM_DECLARE_STATIC_MAPS(InfillPattern)
@@ -1194,6 +1202,9 @@ PRINT_CONFIG_CLASS_DEFINE(
     ((ConfigOptionFloatOrPercent, top_surface_line_width))
     ((ConfigOptionInt, top_shell_layers))
     ((ConfigOptionFloat, top_shell_thickness))
+    ((ConfigOptionFloat, top_surface_expansion))
+    ((ConfigOptionFloat, top_surface_expansion_margin))
+    ((ConfigOptionEnum<TopSurfaceExpansionDirection>, top_surface_expansion_direction))
     ((ConfigOptionFloatsNullable, top_surface_speed))
     //BBS
     ((ConfigOptionBoolsNullable,            enable_overhang_speed))

src/libslic3r/PrintObject.cpp

@@ -4,6 +4,7 @@
 #include "Print.hpp"
 #include "BoundingBox.hpp"
 #include "ClipperUtils.hpp"
+#include "Clipper2Utils.hpp"
 #include "ElephantFootCompensation.hpp"
 #include "Geometry.hpp"
 #include "I18N.hpp"
@@ -1297,6 +1298,9 @@ bool PrintObject::invalidate_state_by_config_options(
             || opt_key == "infill_combination_max_layer_height"
             || opt_key == "bottom_shell_thickness"
             || opt_key == "top_shell_thickness"
+            || opt_key == "top_surface_expansion"
+            || opt_key == "top_surface_expansion_margin"
+            || opt_key == "top_surface_expansion_direction"
             || opt_key == "minimum_sparse_infill_area"
             || opt_key == "sparse_infill_filament_id"
             || opt_key == "internal_solid_filament_id"
@@ -1686,6 +1690,69 @@ void PrintObject::detect_surfaces_type()
                         }
                     }
 
+                    // ORCA: Expand the top surfaces outward by top_surface_expansion in every direction. This
+                    // enlarges the top solid infill and, in particular, grows it over the covered material left
+                    // by features rising from the middle of a top surface (filling holes and joining tops so the
+                    // features rest on it). The expansion stays inside the section it belongs to: each connected
+                    // solid island has its own outer wall, so the top is grown within each island separately and
+                    // clipped to it - growing one island's top across the gap into another island (which may have
+                    // no top surface, leaving a partially filled layer) is never allowed. The top infill sits
+                    // inside the perimeters, so the margin is measured from the walls: the island is inset by the
+                    // band the walls consume (outer wall + inner walls) plus the configured margin, making that
+                    // value the real clearance between the expanded top and the walls (avoiding a hull line). The
+                    // original top is unioned back in, so where it already sits within that band it is kept as-is.
+                    // Never claims a bottom surface.
+                    const double top_expansion = layerm->region().config().top_surface_expansion.value;
+                    if (top_expansion > 0. && ! top.empty()) {
+                        const double     d        = scale_(top_expansion);
+                        const auto       jt       = Clipper2Lib::JoinType::Miter;
+                        const ExPolygons T        = union_ex(to_expolygons(top));
+                        const int    wall_loops = layerm->region().config().wall_loops.value;
+                        const double wall_band  = wall_loops <= 0 ? 0. :
+                            double(layerm->flow(frExternalPerimeter).scaled_width()) +
+                            double(layerm->flow(frPerimeter).scaled_width()) * double(wall_loops - 1);
+                        const double margin     = scale_(layerm->region().config().top_surface_expansion_margin.value);
+                        // minimum real top to act on: ignore anything thinner than ~2 top-infill lines
+                        const float  min_top    = float(layerm->flow(frTopSolidInfill).scaled_width());
+                        const auto   direction  = layerm->region().config().top_surface_expansion_direction.value;
+
+                        ExPolygons grown;
+                        for (const ExPolygon &island : union_ex(layerm_slices_surfaces)) {
+                            // The top infill only exists inside the perimeters, so seed and measure from the infill
+                            // region (the island minus the wall band), not the raw slice. A section whose only
+                            // exposed top lies in the wall band - i.e. a layer where the top is just the walls
+                            // themselves - has no infill here and is skipped, instead of being flooded inward by
+                            // the expansion. Thin slivers inside the infill region are dropped by the opening too.
+                            const ExPolygons infill_region = wall_band > 0. ? offset_ex(island, -float(wall_band)) : ExPolygons{ island };
+                            const ExPolygons island_top    = intersection_ex(T, infill_region);
+                            if (opening_ex(island_top, min_top).empty())
+                                continue; // no real top infill in this section - never expand into it
+
+                            // grow by d, then keep only the part allowed by the configured direction: inward fills
+                            // the holes/gaps left by features (clip the growth back to the top's own filled outline,
+                            // which leaves the outer edge fixed), outward grows the outer edge toward the walls (drop
+                            // the growth that fell into the original holes), and inward+outward keeps both.
+                            ExPolygons expanded = offset_ex_2(island_top, d, jt);
+                            if (direction != TopSurfaceExpansionDirection::InwardAndOutward) {
+                                ExPolygons outline; // the top with its holes filled (same outer edge)
+                                outline.reserve(island_top.size());
+                                for (const ExPolygon &ex : island_top)
+                                    outline.emplace_back(ex.contour);
+                                outline = union_ex(outline);
+                                expanded = direction == TopSurfaceExpansionDirection::Inward ?
+                                    intersection_ex(expanded, outline) :              // only growth into the holes
+                                    diff_ex(expanded, diff_ex(outline, island_top));  // only growth past the outer edge
+                            }
+                            // hold the expansion clear of the walls by the configured margin
+                            const ExPolygons allowed = margin > 0. ? offset_ex(infill_region, -float(margin)) : infill_region;
+                            append(grown, intersection_ex(expanded, allowed));
+                        }
+
+                        ExPolygons new_top = diff_ex(union_ex(T, grown), to_expolygons(bottom));
+                        top.clear();
+                        surfaces_append(top, std::move(new_top), stTop);
+                    }
+
         #ifdef SLIC3R_DEBUG_SLICE_PROCESSING
                     {
                         static int iRun = 0;

src/slic3r/GUI/ConfigManipulation.cpp

@@ -713,6 +713,13 @@ void ConfigManipulation::toggle_print_fff_options(DynamicPrintConfig *config, in
     toggle_field("top_layer_direction", has_top_shell);
     toggle_field("bottom_layer_direction", has_bottom_shell);
 
+    toggle_line("top_surface_expansion", has_top_shell);
+    toggle_line("top_surface_expansion_margin", has_top_shell);
+    bool has_top_surface_expansion = config->opt_float("top_surface_expansion") > 0;
+    toggle_field("top_surface_expansion_margin", has_top_surface_expansion);
+    toggle_line("top_surface_expansion_direction", has_top_shell);
+    toggle_field("top_surface_expansion_direction", has_top_surface_expansion);
+
     for (auto el : { "infill_direction", "sparse_infill_line_width", "gap_fill_target","filter_out_gap_fill","infill_wall_overlap",
         "bridge_angle", "internal_bridge_angle", "relative_bridge_angle",
         "solid_infill_direction", "solid_infill_rotate_template", "internal_solid_infill_pattern", "internal_solid_filament_id", "top_surface_filament_id", "bottom_surface_filament_id",

src/slic3r/GUI/GUI_Factories.cpp

@@ -132,6 +132,9 @@ std::map<std::string, std::vector<SimpleSettingData>> SettingsFactory::PART_CATE
        {"infill_anchor", "", 1},
        {"infill_anchor_max", "", 1},
        {"top_surface_pattern", "", 1},
+       {"top_surface_expansion", "", 1},
+       {"top_surface_expansion_margin", "", 1},
+       {"top_surface_expansion_direction", "", 1},
        {"bottom_surface_pattern", "", 1},
        {"internal_solid_infill_pattern", "", 1},
        {"align_infill_direction_to_model", "", 1},
@@ -187,7 +190,7 @@ std::vector<SimpleSettingData> SettingsFactory::get_visible_options(const std::s
         //Quality
         "wall_infill_order", "ironing_type", "inner_wall_line_width", "outer_wall_line_width", "top_surface_line_width",
         //Shell
-        "wall_loops", "top_shell_layers", "bottom_shell_layers", "top_shell_thickness", "bottom_shell_thickness",
+        "wall_loops", "top_shell_layers", "bottom_shell_layers", "top_shell_thickness", "bottom_shell_thickness", "top_surface_expansion", "top_surface_expansion_margin", "top_surface_expansion_direction",
         //Infill
         "sparse_infill_density", "sparse_infill_pattern", "top_surface_pattern", "bottom_surface_pattern", "infill_combination", "infill_direction", "infill_wall_overlap",
         //speed

src/slic3r/GUI/Tab.cpp

@@ -2743,6 +2743,10 @@ void TabPrint::build()
         optgroup->append_single_option_line("top_surface_density", "strength_settings_top_bottom_shells#surface-density");
         optgroup->append_single_option_line("top_surface_pattern", "strength_settings_top_bottom_shells#surface-pattern");
         optgroup->append_single_option_line("top_layer_direction", "strength_settings_infill#top-direction");
+        optgroup->append_single_option_line("top_surface_hole_contraction", "strength_settings_top_bottom_shells#surface-hole-contraction");
+        optgroup->append_single_option_line("top_surface_expansion", "strength_settings_top_bottom_shells#surface-expansion");
+        optgroup->append_single_option_line("top_surface_expansion_margin", "strength_settings_top_bottom_shells#surface-expansion-margin");
+        optgroup->append_single_option_line("top_surface_expansion_direction", "strength_settings_top_bottom_shells#surface-expansion-direction");
         optgroup->append_single_option_line("bottom_shell_layers", "strength_settings_top_bottom_shells#shell-layers");
         optgroup->append_single_option_line("bottom_shell_thickness", "strength_settings_top_bottom_shells#shell-thickness");
         optgroup->append_single_option_line("bottom_surface_density", "strength_settings_top_bottom_shells#surface-density");