From 7bc8074e694ae26b440dff891e04a39e480403e1 Mon Sep 17 00:00:00 2001
From: Noisyfox <timemanager.rick@gmail.com>
Date: Sat, 9 May 2026 16:18:49 +0800
Subject: [PATCH] Remap paint after split to objects

---
 src/OrcaSlicer.cpp        |  2 +-
 src/libslic3r/Model.cpp   | 10 +++++++++-
 src/libslic3r/Model.hpp   |  2 +-
 src/slic3r/GUI/Plater.cpp |  2 +-
 4 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/src/OrcaSlicer.cpp b/src/OrcaSlicer.cpp
index ba52f6787b2..b258e096d40 100644
--- a/src/OrcaSlicer.cpp
+++ b/src/OrcaSlicer.cpp
@@ -4450,7 +4450,7 @@ int CLI::run(int argc, char **argv)
                 size_t num_objects = model.objects.size();
                 for (size_t i = 0; i < num_objects; ++ i) {
                     ModelObjectPtrs new_objects;
-                    model.objects.front()->split(&new_objects);
+                    model.objects.front()->split(&new_objects, false); // TODO: add cli option to enable this?
                     model.delete_object(size_t(0));
                 }
             }
diff --git a/src/libslic3r/Model.cpp b/src/libslic3r/Model.cpp
index 57a114479bf..09751cd7df2 100644
--- a/src/libslic3r/Model.cpp
+++ b/src/libslic3r/Model.cpp
@@ -2028,13 +2028,14 @@ static void invalidate_translations(ModelObject* object, const ModelInstance* sr
     }
 }
 
-void ModelObject::split(ModelObjectPtrs* new_objects)
+void ModelObject::split(ModelObjectPtrs* new_objects, const bool remap_paint)
 {
     std::vector<TriangleMesh> all_meshes;
     std::vector<Transform3d> all_transfos;
     std::vector<std::pair<int, int>> volume_mesh_counts;
     all_meshes.reserve(this->volumes.size() * 5);
     bool is_multi_volume_object = (this->volumes.size() > 1);
+    std::optional<TriangleSelector::SavedPainting> saved_painting;
 
     for (int volume_idx = 0; volume_idx < this->volumes.size(); volume_idx++) {
         ModelVolume* volume = this->volumes[volume_idx];
@@ -2046,6 +2047,10 @@ void ModelObject::split(ModelObjectPtrs* new_objects)
             volume->text_configuration.reset();
 
         if (!is_multi_volume_object) {
+            if (remap_paint) {
+                // Save painting so we could restore them after the mesh split
+                saved_painting = volume->save_painting();
+            }
             //BBS: not multi volume object, then split mesh.
             std::vector<TriangleMesh> volume_meshes = volume->mesh().split();
             int mesh_count = 0;
@@ -2123,6 +2128,9 @@ void ModelObject::split(ModelObjectPtrs* new_objects)
                 COPY_FACETS(seam_facets);
                 COPY_FACETS(mmu_segmentation_facets);
                 COPY_FACETS(fuzzy_skin_facets);
+            } else if (saved_painting) {
+                // Geometry changed, attempt to remap them to the new mesh
+                new_vol->restore_painting(saved_painting);
             }
 
             // BBS: clear volume's config, as we already set them into object
diff --git a/src/libslic3r/Model.hpp b/src/libslic3r/Model.hpp
index 5bf345607d1..6a672defb05 100644
--- a/src/libslic3r/Model.hpp
+++ b/src/libslic3r/Model.hpp
@@ -516,7 +516,7 @@ public:
     void delete_connectors();
     void clone_for_cut(ModelObject **obj);
 
-    void split(ModelObjectPtrs*new_objects);
+    void split(ModelObjectPtrs*new_objects, bool remap_paint);
     void merge();
 
     // BBS: Boolean opts - Musang King
diff --git a/src/slic3r/GUI/Plater.cpp b/src/slic3r/GUI/Plater.cpp
index ec74a796e45..f78cc3f9b71 100644
--- a/src/slic3r/GUI/Plater.cpp
+++ b/src/slic3r/GUI/Plater.cpp
@@ -7603,7 +7603,7 @@ void Plater::priv::split_object(int obj_idx, bool auto_drop /* = true */)
 
     wxBusyCursor wait;
     ModelObjectPtrs new_objects;
-    current_model_object->split(&new_objects);
+    current_model_object->split(&new_objects, wxGetApp().app_config->get_bool("keep_painting"));
     if (new_objects.size() == 1)
         // #ysFIXME use notification
         Slic3r::GUI::warning_catcher(q, _L("The selected object couldn't be split."));