Avoid code duplication when naming objects after split

src/PrusaSlicer.cpp

@@ -403,11 +403,7 @@ 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;
-                    ModelObject* front = model.objects.front();
-                    front->split(&new_objects);
-                    unsigned int counter = 1;
-                    for (ModelObject* m : new_objects)
-                        m->name = front->name + "_" + std::to_string(counter++);
+                    model.objects.front()->split(&new_objects);
                     model.delete_object(size_t(0));
                 }
             }

src/libslic3r/Model.cpp

@@ -1282,6 +1282,7 @@ void ModelObject::split(ModelObjectPtrs* new_objects)
 
     ModelVolume* volume = this->volumes.front();
     TriangleMeshPtrs meshptrs = volume->mesh().split();
+    size_t counter = 1;
     for (TriangleMesh *mesh : meshptrs) {
 
         // FIXME: crashes if not satisfied
@@ -1291,7 +1292,8 @@ void ModelObject::split(ModelObjectPtrs* new_objects)
 
         // XXX: this seems to be the only real usage of m_model, maybe refactor this so that it's not needed?
         ModelObject* new_object = m_model->add_object();    
-        new_object->name   = this->name;
+        new_object->name   = this->name + (meshptrs.size() > 1 ? "_" + std::to_string(counter++) : "");
+
         // Don't copy the config's ID.
 		new_object->config.assign_config(this->config);
 		assert(new_object->config.id().valid());

src/slic3r/GUI/Plater.cpp

@@ -2881,10 +2881,6 @@ void Plater::priv::split_object()
     {
         Plater::TakeSnapshot snapshot(q, _L("Split to Objects"));
 
-        unsigned int counter = 1;
-        for (ModelObject* m : new_objects)
-            m->name = current_model_object->name + "_" + std::to_string(counter++);
-
         remove(obj_idx);
 
         // load all model objects at once, otherwise the plate would be rearranged after each one