SPE-1840: Rework multi-material segmentation to work directly on the Voronoi diagram without creating a copy of it.

Previous algorithms assume that they can get an invalid Voronoi diagram. Because of that, during the multi-material segmentation, a copy of the Voronoi diagram was created, and there were several attempts to fix missing vertices and edges. But as it shows, this wasn't a good enough approach and sometimes led to several issues like bleeding layers.

After generalization, our approach for detection and repairs of invalid Voronoi diagrams from Arachne, we could assume that multi-material segmentation gets non-invalid Voronoi diagrams.
With this assumption, we reimplement multi-materials segmentation to work directly on the Voronoi diagram. That should make multi-material segmentation more stable.

So, this should fix several issues like bleeding layers. Also, memory consumption should decrease by a lot. Also, there should be some speedup of multi-materials segmentation.

src/libslic3r/Format/3mf.cpp

@@ -124,7 +124,7 @@ static constexpr const char* PRINTABLE_ATTR = "printable";
 static constexpr const char* INSTANCESCOUNT_ATTR = "instances_count";
 static constexpr const char* CUSTOM_SUPPORTS_ATTR = "slic3rpe:custom_supports";
 static constexpr const char* CUSTOM_SEAM_ATTR = "slic3rpe:custom_seam";
-static constexpr const char* MMU_SEGMENTATION_ATTR = "slic3rpe:mmu_segmentation";
+static constexpr const char* MM_SEGMENTATION_ATTR = "slic3rpe:mmu_segmentation";
 
 static constexpr const char* KEY_ATTR = "key";
 static constexpr const char* VALUE_ATTR = "value";
@@ -362,7 +362,7 @@ namespace Slic3r {
             std::vector<Vec3i> triangles;
             std::vector<std::string> custom_supports;
             std::vector<std::string> custom_seam;
-            std::vector<std::string> mmu_segmentation;
+            std::vector<std::string> mm_segmentation;
 
             bool empty() { return vertices.empty() || triangles.empty(); }
 
@@ -371,7 +371,7 @@ namespace Slic3r {
                 triangles.clear();
                 custom_supports.clear();
                 custom_seam.clear();
-                mmu_segmentation.clear();
+                mm_segmentation.clear();
             }
         };
 
@@ -1830,7 +1830,7 @@ namespace Slic3r {
 
         m_curr_object.geometry.custom_supports.push_back(get_attribute_value_string(attributes, num_attributes, CUSTOM_SUPPORTS_ATTR));
         m_curr_object.geometry.custom_seam.push_back(get_attribute_value_string(attributes, num_attributes, CUSTOM_SEAM_ATTR));
-        m_curr_object.geometry.mmu_segmentation.push_back(get_attribute_value_string(attributes, num_attributes, MMU_SEGMENTATION_ATTR));
+        m_curr_object.geometry.mm_segmentation.push_back(get_attribute_value_string(attributes, num_attributes, MM_SEGMENTATION_ATTR));
         return true;
     }
 
@@ -2320,25 +2320,25 @@ namespace Slic3r {
             if (has_transform)
                 volume->source.transform = Slic3r::Geometry::Transformation(volume_matrix_to_object);
 
-            // recreate custom supports, seam and mmu segmentation from previously loaded attribute
+            // recreate custom supports, seam and mm segmentation from previously loaded attribute
             volume->supported_facets.reserve(triangles_count);
             volume->seam_facets.reserve(triangles_count);
-            volume->mmu_segmentation_facets.reserve(triangles_count);
+            volume->mm_segmentation_facets.reserve(triangles_count);
             for (size_t i=0; i<triangles_count; ++i) {
                 size_t index = volume_data.first_triangle_id + i;
                 assert(index < geometry.custom_supports.size());
                 assert(index < geometry.custom_seam.size());
-                assert(index < geometry.mmu_segmentation.size());
+                assert(index < geometry.mm_segmentation.size());
                 if (! geometry.custom_supports[index].empty())
                     volume->supported_facets.set_triangle_from_string(i, geometry.custom_supports[index]);
                 if (! geometry.custom_seam[index].empty())
                     volume->seam_facets.set_triangle_from_string(i, geometry.custom_seam[index]);
-                if (! geometry.mmu_segmentation[index].empty())
+                if (! geometry.mm_segmentation[index].empty())
-                    volume->mmu_segmentation_facets.set_triangle_from_string(i, geometry.mmu_segmentation[index]);
+                    volume->mm_segmentation_facets.set_triangle_from_string(i, geometry.mm_segmentation[index]);
             }
             volume->supported_facets.shrink_to_fit();
             volume->seam_facets.shrink_to_fit();
-            volume->mmu_segmentation_facets.shrink_to_fit();
+            volume->mm_segmentation_facets.shrink_to_fit();
 
             if (auto &es = volume_data.shape_configuration; es.has_value())
                 volume->emboss_shape = std::move(es);            
@@ -3002,12 +3002,12 @@ namespace Slic3r {
                     output_buffer += "\"";
                 }
 
-                std::string mmu_painting_data_string = volume->mmu_segmentation_facets.get_triangle_as_string(i);
+                std::string mm_painting_data_string = volume->mm_segmentation_facets.get_triangle_as_string(i);
-                if (! mmu_painting_data_string.empty()) {
+                if (! mm_painting_data_string.empty()) {
                     output_buffer += " ";
-                    output_buffer += MMU_SEGMENTATION_ATTR;
+                    output_buffer += MM_SEGMENTATION_ATTR;
                     output_buffer += "=\"";
-                    output_buffer += mmu_painting_data_string;
+                    output_buffer += mm_painting_data_string;
                     output_buffer += "\"";
                 }
 

src/libslic3r/Geometry/Voronoi.cpp

@@ -11,11 +11,11 @@ namespace Slic3r::Geometry {
 
 using PolygonsSegmentIndexConstIt = std::vector<Arachne::PolygonsSegmentIndex>::const_iterator;
 using LinesIt                     = Lines::iterator;
-using ColoredLinesIt              = ColoredLines::iterator;
+using ColoredLinesConstIt         = ColoredLines::const_iterator;
 
 // Explicit template instantiation.
 template void VoronoiDiagram::construct_voronoi(LinesIt, LinesIt, bool);
-template void VoronoiDiagram::construct_voronoi(ColoredLinesIt, ColoredLinesIt, bool);
+template void VoronoiDiagram::construct_voronoi(ColoredLinesConstIt, ColoredLinesConstIt, bool);
 template void VoronoiDiagram::construct_voronoi(PolygonsSegmentIndexConstIt, PolygonsSegmentIndexConstIt, bool);
 
 template<typename SegmentIterator>

src/libslic3r/Geometry/VoronoiUtils.cpp

@@ -8,19 +8,22 @@ namespace Slic3r::Geometry {
 using PolygonsSegmentIndexConstIt = std::vector<Arachne::PolygonsSegmentIndex>::const_iterator;
 using LinesIt                     = Lines::iterator;
 using ColoredLinesIt              = ColoredLines::iterator;
+using ColoredLinesConstIt         = ColoredLines::const_iterator;
 
 // Explicit template instantiation.
 template LinesIt::reference VoronoiUtils::get_source_segment(const VoronoiDiagram::cell_type &, LinesIt, LinesIt);
 template VD::SegmentIt::reference VoronoiUtils::get_source_segment(const VoronoiDiagram::cell_type &, VD::SegmentIt, VD::SegmentIt);
 template ColoredLinesIt::reference VoronoiUtils::get_source_segment(const VoronoiDiagram::cell_type &, ColoredLinesIt, ColoredLinesIt);
+template ColoredLinesConstIt::reference VoronoiUtils::get_source_segment(const VoronoiDiagram::cell_type &, ColoredLinesConstIt, ColoredLinesConstIt);
 template PolygonsSegmentIndexConstIt::reference VoronoiUtils::get_source_segment(const VoronoiDiagram::cell_type &, PolygonsSegmentIndexConstIt, PolygonsSegmentIndexConstIt);
 template Point VoronoiUtils::get_source_point(const VoronoiDiagram::cell_type &, LinesIt, LinesIt);
 template Point VoronoiUtils::get_source_point(const VoronoiDiagram::cell_type &, VD::SegmentIt, VD::SegmentIt);
 template Point VoronoiUtils::get_source_point(const VoronoiDiagram::cell_type &, ColoredLinesIt, ColoredLinesIt);
+template Point VoronoiUtils::get_source_point(const VoronoiDiagram::cell_type &, ColoredLinesConstIt, ColoredLinesConstIt);
 template Point VoronoiUtils::get_source_point(const VoronoiDiagram::cell_type &, PolygonsSegmentIndexConstIt, PolygonsSegmentIndexConstIt);
 template SegmentCellRange<Point> VoronoiUtils::compute_segment_cell_range(const VoronoiDiagram::cell_type &, LinesIt, LinesIt);
 template SegmentCellRange<Point> VoronoiUtils::compute_segment_cell_range(const VoronoiDiagram::cell_type &, VD::SegmentIt, VD::SegmentIt);
-template SegmentCellRange<Point> VoronoiUtils::compute_segment_cell_range(const VoronoiDiagram::cell_type &, ColoredLinesIt, ColoredLinesIt);
+template SegmentCellRange<Point> VoronoiUtils::compute_segment_cell_range(const VoronoiDiagram::cell_type &, ColoredLinesConstIt, ColoredLinesConstIt);
 template SegmentCellRange<Point> VoronoiUtils::compute_segment_cell_range(const VoronoiDiagram::cell_type &, PolygonsSegmentIndexConstIt, PolygonsSegmentIndexConstIt);
 template Points VoronoiUtils::discretize_parabola(const Point &, const Arachne::PolygonsSegmentIndex &, const Point &, const Point &, coord_t, float);
 template Arachne::PolygonsPointIndex VoronoiUtils::get_source_point_index(const VoronoiDiagram::cell_type &, PolygonsSegmentIndexConstIt, PolygonsSegmentIndexConstIt);
@@ -241,7 +244,13 @@ VoronoiUtils::compute_segment_cell_range(const VD::cell_type &cell, const Segmen
 
 Vec2i64 VoronoiUtils::to_point(const VD::vertex_type *vertex)
 {
-    const double x = vertex->x(), y = vertex->y();
+    assert(vertex != nullptr);
+    return VoronoiUtils::to_point(*vertex);
+}
+
+Vec2i64 VoronoiUtils::to_point(const VD::vertex_type &vertex)
+{
+    const double x = vertex.x(), y = vertex.y();
 
     assert(std::isfinite(x) && std::isfinite(y));
     assert(is_in_range<int64_t>(x) && is_in_range<int64_t>(y));

src/libslic3r/Geometry/VoronoiUtils.hpp

@@ -29,6 +29,8 @@ class VoronoiUtils
 public:
     static Vec2i64 to_point(const VD::vertex_type *vertex);
 
+    static Vec2i64 to_point(const VD::vertex_type &vertex);
+
     static bool is_finite(const VD::vertex_type &vertex);
 
     static VD::vertex_type make_rotated_vertex(VD::vertex_type &vertex, double angle);

src/libslic3r/Geometry/VoronoiUtilsCgal.cpp

@@ -19,12 +19,12 @@ namespace Slic3r::Geometry {
 
 using PolygonsSegmentIndexConstIt = std::vector<Arachne::PolygonsSegmentIndex>::const_iterator;
 using LinesIt                     = Lines::iterator;
-using ColoredLinesIt              = ColoredLines::iterator;
+using ColoredLinesConstIt         = ColoredLines::const_iterator;
 
 // Explicit template instantiation.
 template bool VoronoiUtilsCgal::is_voronoi_diagram_planar_angle(const VD &, LinesIt, LinesIt);
 template bool VoronoiUtilsCgal::is_voronoi_diagram_planar_angle(const VD &, VD::SegmentIt, VD::SegmentIt);
-template bool VoronoiUtilsCgal::is_voronoi_diagram_planar_angle(const VD &, ColoredLinesIt, ColoredLinesIt);
+template bool VoronoiUtilsCgal::is_voronoi_diagram_planar_angle(const VD &, ColoredLinesConstIt, ColoredLinesConstIt);
 template bool VoronoiUtilsCgal::is_voronoi_diagram_planar_angle(const VD &, PolygonsSegmentIndexConstIt, PolygonsSegmentIndexConstIt);
 
 // The tangent vector of the parabola is computed based on the Proof of the reflective property.

src/libslic3r/Model.cpp

@@ -1237,7 +1237,7 @@ void ModelObject::convert_units(ModelObjectPtrs& new_objects, ConversionType con
 
             vol->supported_facets.assign(volume->supported_facets);
             vol->seam_facets.assign(volume->seam_facets);
-            vol->mmu_segmentation_facets.assign(volume->mmu_segmentation_facets);
+            vol->mm_segmentation_facets.assign(volume->mm_segmentation_facets);
 
             // Perform conversion only if the target "imperial" state is different from the current one.
             // This check supports conversion of "mixed" set of volumes, each with different "imperial" state.
@@ -1349,7 +1349,7 @@ void ModelVolume::reset_extra_facets()
 {
     this->supported_facets.reset();
     this->seam_facets.reset();
-    this->mmu_segmentation_facets.reset();
+    this->mm_segmentation_facets.reset();
 }
 
 
@@ -1915,7 +1915,7 @@ void ModelVolume::assign_new_unique_ids_recursive()
     config.set_new_unique_id();
     supported_facets.set_new_unique_id();
     seam_facets.set_new_unique_id();
-    mmu_segmentation_facets.set_new_unique_id();
+    mm_segmentation_facets.set_new_unique_id();
 }
 
 void ModelVolume::rotate(double angle, Axis axis)
@@ -2224,7 +2224,7 @@ bool model_mmu_segmentation_data_changed(const ModelObject& mo, const ModelObjec
 {
     return model_property_changed(mo, mo_new, 
         [](const ModelVolumeType t) { return t == ModelVolumeType::MODEL_PART; }, 
-        [](const ModelVolume &mv_old, const ModelVolume &mv_new){ return mv_old.mmu_segmentation_facets.timestamp_matches(mv_new.mmu_segmentation_facets); });
+        [](const ModelVolume &mv_old, const ModelVolume &mv_new){ return mv_old.mm_segmentation_facets.timestamp_matches(mv_new.mm_segmentation_facets); });
 }
 
 bool model_has_parameter_modifiers_in_objects(const Model &model)

src/libslic3r/Model.hpp

@@ -823,8 +823,8 @@ public:
     // List of seam enforcers/blockers.
     FacetsAnnotation    seam_facets;
 
-    // List of mesh facets painted for MMU segmentation.
+    // List of mesh facets painted for MM segmentation.
-    FacetsAnnotation    mmu_segmentation_facets;
+    FacetsAnnotation    mm_segmentation_facets;
 
     // Is set only when volume is Embossed Text type
     // Contain information how to re-create volume
@@ -929,12 +929,12 @@ public:
         this->config.set_new_unique_id();
         this->supported_facets.set_new_unique_id();
         this->seam_facets.set_new_unique_id();
-        this->mmu_segmentation_facets.set_new_unique_id();
+        this->mm_segmentation_facets.set_new_unique_id();
     }
 
     bool is_fdm_support_painted() const { return !this->supported_facets.empty(); }
     bool is_seam_painted() const { return !this->seam_facets.empty(); }
-    bool is_mm_painted() const { return !this->mmu_segmentation_facets.empty(); }
+    bool is_mm_painted() const { return !this->mm_segmentation_facets.empty(); }
 
 protected:
 	friend class Print;
@@ -973,11 +973,11 @@ private:
         assert(this->config.id().valid());
         assert(this->supported_facets.id().valid());
         assert(this->seam_facets.id().valid());
-        assert(this->mmu_segmentation_facets.id().valid());
+        assert(this->mm_segmentation_facets.id().valid());
         assert(this->id() != this->config.id());
         assert(this->id() != this->supported_facets.id());
         assert(this->id() != this->seam_facets.id());
-        assert(this->id() != this->mmu_segmentation_facets.id());
+        assert(this->id() != this->mm_segmentation_facets.id());
         return true;
     }
 
@@ -1003,23 +1003,23 @@ private:
         ObjectBase(other),
         name(other.name), source(other.source), m_mesh(other.m_mesh), m_convex_hull(other.m_convex_hull),
         config(other.config), m_type(other.m_type), object(object), m_transformation(other.m_transformation),
-        supported_facets(other.supported_facets), seam_facets(other.seam_facets), mmu_segmentation_facets(other.mmu_segmentation_facets),
+        supported_facets(other.supported_facets), seam_facets(other.seam_facets), mm_segmentation_facets(other.mm_segmentation_facets),
         cut_info(other.cut_info), text_configuration(other.text_configuration), emboss_shape(other.emboss_shape)
     {
 		assert(this->id().valid()); 
         assert(this->config.id().valid()); 
         assert(this->supported_facets.id().valid());
         assert(this->seam_facets.id().valid());
-        assert(this->mmu_segmentation_facets.id().valid());
+        assert(this->mm_segmentation_facets.id().valid());
         assert(this->id() != this->config.id());
         assert(this->id() != this->supported_facets.id());
         assert(this->id() != this->seam_facets.id());
-        assert(this->id() != this->mmu_segmentation_facets.id());
+        assert(this->id() != this->mm_segmentation_facets.id());
 		assert(this->id() == other.id());
         assert(this->config.id() == other.config.id());
         assert(this->supported_facets.id() == other.supported_facets.id());
         assert(this->seam_facets.id() == other.seam_facets.id());
-        assert(this->mmu_segmentation_facets.id() == other.mmu_segmentation_facets.id());
+        assert(this->mm_segmentation_facets.id() == other.mm_segmentation_facets.id());
         this->set_material_id(other.material_id());
     }
     // Providing a new mesh, therefore this volume will get a new unique ID assigned.
@@ -1031,11 +1031,11 @@ private:
         assert(this->config.id().valid()); 
         assert(this->supported_facets.id().valid());
         assert(this->seam_facets.id().valid());
-        assert(this->mmu_segmentation_facets.id().valid());
+        assert(this->mm_segmentation_facets.id().valid());
         assert(this->id() != this->config.id());
         assert(this->id() != this->supported_facets.id());
         assert(this->id() != this->seam_facets.id());
-        assert(this->id() != this->mmu_segmentation_facets.id());
+        assert(this->id() != this->mm_segmentation_facets.id());
 		assert(this->id() != other.id());
         assert(this->config.id() == other.config.id());
         this->set_material_id(other.material_id());
@@ -1046,11 +1046,11 @@ private:
         assert(this->config.id() != other.config.id()); 
         assert(this->supported_facets.id() != other.supported_facets.id());
         assert(this->seam_facets.id() != other.seam_facets.id());
-        assert(this->mmu_segmentation_facets.id() != other.mmu_segmentation_facets.id());
+        assert(this->mm_segmentation_facets.id() != other.mm_segmentation_facets.id());
         assert(this->id() != this->config.id());
         assert(this->supported_facets.empty());
         assert(this->seam_facets.empty());
-        assert(this->mmu_segmentation_facets.empty());
+        assert(this->mm_segmentation_facets.empty());
     }
 
     ModelVolume& operator=(ModelVolume &rhs) = delete;
@@ -1058,19 +1058,19 @@ private:
 	friend class cereal::access;
 	friend class UndoRedo::StackImpl;
 	// Used for deserialization, therefore no IDs are allocated.
-	ModelVolume() : ObjectBase(-1), config(-1), supported_facets(-1), seam_facets(-1), mmu_segmentation_facets(-1), object(nullptr) {
+	ModelVolume() : ObjectBase(-1), config(-1), supported_facets(-1), seam_facets(-1), mm_segmentation_facets(-1), object(nullptr) {
 		assert(this->id().invalid());
         assert(this->config.id().invalid());
         assert(this->supported_facets.id().invalid());
         assert(this->seam_facets.id().invalid());
-        assert(this->mmu_segmentation_facets.id().invalid());
+        assert(this->mm_segmentation_facets.id().invalid());
 	}
 	template<class Archive> void load(Archive &ar) {
 		bool has_convex_hull;
         ar(name, source, m_mesh, m_type, m_material_id, m_transformation, m_is_splittable, has_convex_hull, cut_info);
         cereal::load_by_value(ar, supported_facets);
         cereal::load_by_value(ar, seam_facets);
-        cereal::load_by_value(ar, mmu_segmentation_facets);
+        cereal::load_by_value(ar, mm_segmentation_facets);
         cereal::load_by_value(ar, config);
         cereal::load(ar, text_configuration);
         cereal::load(ar, emboss_shape);
@@ -1088,7 +1088,7 @@ private:
         ar(name, source, m_mesh, m_type, m_material_id, m_transformation, m_is_splittable, has_convex_hull, cut_info);
         cereal::save_by_value(ar, supported_facets);
         cereal::save_by_value(ar, seam_facets);
-        cereal::save_by_value(ar, mmu_segmentation_facets);
+        cereal::save_by_value(ar, mm_segmentation_facets);
         cereal::save_by_value(ar, config);
         cereal::save(ar, text_configuration);
         cereal::save(ar, emboss_shape);

src/libslic3r/PrintApply.cpp

@@ -78,8 +78,8 @@ static inline void model_volume_list_copy_configs(ModelObject &model_object_dst,
         mv_dst.supported_facets.assign(mv_src.supported_facets);
         assert(mv_dst.seam_facets.id() == mv_src.seam_facets.id());
         mv_dst.seam_facets.assign(mv_src.seam_facets);
-        assert(mv_dst.mmu_segmentation_facets.id() == mv_src.mmu_segmentation_facets.id());
+        assert(mv_dst.mm_segmentation_facets.id() == mv_src.mm_segmentation_facets.id());
-        mv_dst.mmu_segmentation_facets.assign(mv_src.mmu_segmentation_facets);
+        mv_dst.mm_segmentation_facets.assign(mv_src.mm_segmentation_facets);
         //FIXME what to do with the materials?
         // mv_dst.m_material_id = mv_src.m_material_id;
         ++ i_src;
@@ -1374,7 +1374,7 @@ Print::ApplyStatus Print::apply(const Model &model, DynamicPrintConfig new_full_
         std::vector<unsigned int> painting_extruders;
         if (const auto &volumes = print_object.model_object()->volumes;
             num_extruders > 1 &&
-            std::find_if(volumes.begin(), volumes.end(), [](const ModelVolume *v) { return ! v->mmu_segmentation_facets.empty(); }) != volumes.end()) {
+            std::find_if(volumes.begin(), volumes.end(), [](const ModelVolume *v) { return ! v->mm_segmentation_facets.empty(); }) != volumes.end()) {
             //FIXME be more specific! Don't enumerate extruders that are not used for painting!
             painting_extruders.assign(num_extruders, 0);
             std::iota(painting_extruders.begin(), painting_extruders.end(), 1);

src/libslic3r/PrintObjectSlice.cpp

@@ -728,7 +728,7 @@ void PrintObject::slice_volumes()
     // Is any ModelVolume MMU painted?
     if (const auto& volumes = this->model_object()->volumes;
         m_print->config().nozzle_diameter.size() > 1 &&
-        std::find_if(volumes.begin(), volumes.end(), [](const ModelVolume* v) { return !v->mmu_segmentation_facets.empty(); }) != volumes.end()) {
+        std::find_if(volumes.begin(), volumes.end(), [](const ModelVolume* v) { return !v->mm_segmentation_facets.empty(); }) != volumes.end()) {
 
         // If XY Size compensation is also enabled, notify the user that XY Size compensation
         // would not be used because the object is multi-material painted.

src/slic3r/GUI/GLCanvas3D.cpp

@@ -4922,7 +4922,7 @@ void GLCanvas3D::_render_thumbnail_internal(ThumbnailData& thumbnail_data, const
     for (GLVolume *vol : visible_volumes) {
         const int obj_idx = vol->object_idx();
         const int vol_idx = vol->volume_idx();
-        const bool render_as_painted = is_enabled_painted_thumbnail && obj_idx >= 0 && vol_idx >= 0 && !model_objects[obj_idx]->volumes[vol_idx]->mmu_segmentation_facets.empty();
+        const bool render_as_painted = is_enabled_painted_thumbnail && obj_idx >= 0 && vol_idx >= 0 && !model_objects[obj_idx]->volumes[vol_idx]->mm_segmentation_facets.empty();
         GLShaderProgram* shader = wxGetApp().get_shader(render_as_painted ? "mm_gouraud" : "gouraud_light");
         if (shader == nullptr)
             continue;
@@ -4958,7 +4958,7 @@ void GLCanvas3D::_render_thumbnail_internal(ThumbnailData& thumbnail_data, const
             const ModelVolume& model_volume = *model_objects[obj_idx]->volumes[vol_idx];
             const size_t extruder_idx = get_extruder_color_idx(model_volume, extruders_count);
             TriangleSelectorMmGui ts(model_volume.mesh(), extruders_colors, extruders_colors[extruder_idx]);
-            ts.deserialize(model_volume.mmu_segmentation_facets.get_data(), true);
+            ts.deserialize(model_volume.mm_segmentation_facets.get_data(), true);
             ts.request_update_render_data();
 
             ts.render(nullptr, model_matrix);

src/slic3r/GUI/GUI_ObjectList.cpp

@@ -1905,7 +1905,7 @@ void ObjectList::del_info_item(const int obj_idx, InfoItemType type)
         cnv->get_gizmos_manager().reset_all_states();
         Plater::TakeSnapshot(plater, _L("Remove Multi Material painting"));
         for (ModelVolume* mv : (*m_objects)[obj_idx]->volumes)
-            mv->mmu_segmentation_facets.reset();
+            mv->mm_segmentation_facets.reset();
         break;
 
     case InfoItemType::Sinking:
@@ -2897,7 +2897,7 @@ void ObjectList::update_info_items(size_t obj_idx, wxDataViewItemArray* selectio
                                       [type](const ModelVolume *mv) {
                                           return !(type == InfoItemType::CustomSupports ? mv->supported_facets.empty() :
                                                    type == InfoItemType::CustomSeam     ? mv->seam_facets.empty() :
-                                                                                          mv->mmu_segmentation_facets.empty());
+                                                                                          mv->mm_segmentation_facets.empty());
                                       });
             break;
 

src/slic3r/GUI/GUI_Preview.cpp

@@ -648,7 +648,7 @@ void Preview::update_layers_slider_mode()
                         if ((volume->config.has("extruder") && 
                             volume->config.option("extruder")->getInt() != 0 && // extruder isn't default
                             volume->config.option("extruder")->getInt() != extruder) ||
-                            !volume->mmu_segmentation_facets.empty())
+                            !volume->mm_segmentation_facets.empty())
                             return false;
 
                     for (const auto& range : object->layer_config_ranges)

src/slic3r/GUI/Gizmos/GLGizmoMmuSegmentation.cpp

@@ -517,7 +517,7 @@ void GLGizmoMmuSegmentation::update_model_object() const
         if (! mv->is_model_part())
             continue;
         ++idx;
-        updated |= mv->mmu_segmentation_facets.set(*m_triangle_selectors[idx].get());
+        updated |= mv->mm_segmentation_facets.set(*m_triangle_selectors[idx].get());
     }
 
     if (updated) {
@@ -547,7 +547,7 @@ void GLGizmoMmuSegmentation::init_model_triangle_selectors()
         size_t extruder_idx = get_extruder_color_idx(*mv, extruders_count);
         m_triangle_selectors.emplace_back(std::make_unique<TriangleSelectorMmGui>(*mesh, m_modified_extruders_colors, m_original_extruders_colors[extruder_idx]));
         // Reset of TriangleSelector is done inside TriangleSelectorMmGUI's constructor, so we don't need it to perform it again in deserialize().
-        m_triangle_selectors.back()->deserialize(mv->mmu_segmentation_facets.get_data(), false);
+        m_triangle_selectors.back()->deserialize(mv->mm_segmentation_facets.get_data(), false);
         m_triangle_selectors.back()->request_update_render_data();
     }
     m_original_volumes_extruder_idxs = get_extruder_id_for_volumes(*mo);

src/slic3r/GUI/Plater.cpp

@@ -3702,7 +3702,7 @@ bool Plater::priv::replace_volume_with_stl(int object_idx, int volume_idx, const
         // We need to make sure that the painted data point to existing triangles.
         new_volume->supported_facets.assign(old_volume->supported_facets);
         new_volume->seam_facets.assign(old_volume->seam_facets);
-        new_volume->mmu_segmentation_facets.assign(old_volume->mmu_segmentation_facets);
+        new_volume->mm_segmentation_facets.assign(old_volume->mm_segmentation_facets);
     }
     std::swap(old_model_object->volumes[volume_idx], old_model_object->volumes.back());
     old_model_object->delete_volume(old_model_object->volumes.size() - 1);
@@ -7918,10 +7918,10 @@ void Plater::clear_before_change_mesh(int obj_idx, const std::string &notificati
     // may be different and they would make no sense.
     bool paint_removed = false;
     for (ModelVolume* mv : mo->volumes) {
-        paint_removed |= ! mv->supported_facets.empty() || ! mv->seam_facets.empty() || ! mv->mmu_segmentation_facets.empty();
+        paint_removed |= ! mv->supported_facets.empty() || ! mv->seam_facets.empty() || ! mv->mm_segmentation_facets.empty();
         mv->supported_facets.reset();
         mv->seam_facets.reset();
-        mv->mmu_segmentation_facets.reset();
+        mv->mm_segmentation_facets.reset();
     }
     if (paint_removed) {
         // snapshot_time is captured by copy so the lambda knows where to undo/redo to.