Cut Improvements/Bug Fixing

* Context menu: Suppress "Simplify model" for cut object
* CutGizmo:
  * Disable gizmo for dowel object
  * Invalidate cut plane position after update of Bounding box
  * Suppress Frustum style for connectors with Dowel type
  * Rectangle selection: Fixed processing on LeftUp
* Selection on Canvas: Suppress to move NEGATIVE_VOLUME if it's a connector
* Model:cut: Fixed a bug in add_cut_volume(). Cut info wasn't copied to the new volume

src/libslic3r/Model.cpp

@@ -1424,6 +1424,7 @@ static void add_cut_volume(TriangleMesh& mesh, ModelObject* object, const ModelV
     assert(vol->config.id().valid());
     assert(vol->config.id() != src_volume->config.id());
     vol->set_material(src_volume->material_id(), *src_volume->material());
+    vol->cut_info = src_volume->cut_info;
 }
 
 void ModelObject::process_solid_part_cut(ModelVolume* volume, const Transform3d& instance_matrix, const Transform3d& cut_matrix,

src/slic3r/GUI/GLCanvas3D.cpp

@@ -3529,7 +3529,8 @@ void GLCanvas3D::on_mouse(wxMouseEvent& evt)
                     const int volume_idx = get_first_hover_volume_idx();
                     BoundingBoxf3 volume_bbox = m_volumes.volumes[volume_idx]->transformed_bounding_box();
                     volume_bbox.offset(1.0);
-                    if ((!any_gizmo_active || !evt.CmdDown()) && volume_bbox.contains(m_mouse.scene_position)) {
+                    const bool is_cut_connector_selected = m_selection.is_any_connector();
+                    if ((!any_gizmo_active || !evt.CmdDown()) && volume_bbox.contains(m_mouse.scene_position) && !is_cut_connector_selected) {
                         m_volumes.volumes[volume_idx]->hover = GLVolume::HS_None;
                         // The dragging operation is initiated.
                         m_mouse.drag.move_volume_idx = volume_idx;

src/slic3r/GUI/GUI_Factories.cpp

@@ -1080,6 +1080,9 @@ wxMenu* MenuFactory::multi_selection_menu()
     wxDataViewItemArray sels;
     obj_list()->GetSelections(sels);
 
+    if (sels.IsEmpty())
+        return nullptr;
+
     for (const wxDataViewItem& item : sels)
         if (!(list_model()->GetItemType(item) & (itVolume | itObject | itInstance)))
             // show this menu only for Objects(Instances mixed with Objects)/Volumes selection

src/slic3r/GUI/GUI_ObjectList.cpp

@@ -3806,6 +3806,8 @@ void ObjectList::update_selections_on_canvas()
 
     if (sel_cnt == 1) {
         wxDataViewItem item = GetSelection();
+        if (m_objects_model->GetInfoItemType(item) == InfoItemType::CutConnectors)
+            selection.remove_all();
         if (m_objects_model->GetItemType(item) & (itSettings | itInstanceRoot | itLayerRoot | itLayer))
             add_to_selection(m_objects_model->GetParent(item), selection, instance_idx, mode);
         else

src/slic3r/GUI/Gizmos/GLGizmoCut.cpp

@@ -963,9 +963,30 @@ void GLGizmoCut3D::on_set_hover_id()
 
 bool GLGizmoCut3D::on_is_activable() const
 {
+    const Selection& selection = m_parent.get_selection();
+    const int object_idx = selection.get_object_idx();
+    if (object_idx < 0)
+        return false;
+
+    bool is_dowel_object = false;
+    if (const ModelObject* mo = wxGetApp().plater()->model().objects[object_idx]; mo->is_cut()) {
+        int solid_connector_cnt = 0;
+        int connectors_cnt = 0;
+        for (const ModelVolume* volume : mo->volumes) {
+            if (volume->is_cut_connector()) {
+                connectors_cnt++;
+                if (volume->is_model_part())
+                    solid_connector_cnt++;
+            }
+            if (connectors_cnt > 1)
+                break;
+        }
+        is_dowel_object = connectors_cnt == 1 && solid_connector_cnt == 1;
+    }
+
     // This is assumed in GLCanvas3D::do_rotate, do not change this
     // without updating that function too.
-    return m_parent.get_selection().is_single_full_instance();
+    return selection.is_single_full_instance() && !is_dowel_object;
 }
 
 bool GLGizmoCut3D::on_is_selectable() const
@@ -1200,6 +1221,9 @@ bool GLGizmoCut3D::update_bb()
 {
     const BoundingBoxf3 box = bounding_box();
     if (m_max_pos != box.max || m_min_pos != box.min) {
+
+        invalidate_cut_plane();
+
         m_max_pos = box.max;
         m_min_pos = box.min;
         m_bb_center = box.center();
@@ -1412,8 +1436,14 @@ void GLGizmoCut3D::render_connectors_input_window(CutConnectors &connectors)
     if (type_changed)
         apply_selected_connectors([this, &connectors] (size_t idx) { connectors[idx].attribs.type = CutConnectorType(m_connector_type); });
 
+    m_imgui->disabled_begin(m_connector_type == CutConnectorType::Dowel);
+    if (type_changed && m_connector_type == CutConnectorType::Dowel) {
+        m_connector_style = size_t(CutConnectorStyle::Prizm);
+        apply_selected_connectors([this, &connectors](size_t idx) { connectors[idx].attribs.style = CutConnectorStyle(m_connector_style); });
+    }
     if (render_combo(_u8L("Style"), m_connector_styles, m_connector_style))
         apply_selected_connectors([this, &connectors](size_t idx) { connectors[idx].attribs.style = CutConnectorStyle(m_connector_style); });
+    m_imgui->disabled_end();
 
     if (render_combo(_u8L("Shape"), m_connector_shapes, m_connector_shape_id))
         apply_selected_connectors([this, &connectors](size_t idx) { connectors[idx].attribs.shape = CutConnectorShape(m_connector_shape_id); });
@@ -1850,8 +1880,6 @@ void GLGizmoCut3D::perform_cut(const Selection& selection)
     else {
         // the object is SLA-elevated and the plane is under it.
     }
-
-    invalidate_cut_plane();
 }
 
 
@@ -2136,7 +2164,7 @@ bool GLGizmoCut3D::gizmo_event(SLAGizmoEventType action, const Vec2d& mouse_posi
         return true;
     }
 
-    if (action == SLAGizmoEventType::LeftUp) {
+    if (action == SLAGizmoEventType::LeftUp && !m_selection_rectangle.is_dragging()) {
         if ((m_ldown_mouse_position - mouse_position).norm() < 5.)
             unselect_all_connectors();
         return is_selection_changed(alt_down, shift_down);

src/slic3r/GUI/Plater.cpp

@@ -2976,9 +2976,6 @@ void Plater::priv::object_list_changed()
     const bool model_fits = view3D->get_canvas3d()->check_volumes_outside_state() == ModelInstancePVS_Inside;
 
     sidebar->enable_buttons(!model.objects.empty() && !export_in_progress && model_fits);
-
-    // invalidate CutGizmo after changes in ObjectList
-    static_cast<GLGizmoCut3D*>(q->canvas3D()->get_gizmos_manager().get_gizmo(GLGizmosManager::Cut))->invalidate_cut_plane();
 }
 
 void Plater::priv::select_all()
@@ -4930,8 +4927,12 @@ bool Plater::priv::can_fix_through_netfabb() const
 
 bool Plater::priv::can_simplify() const
 {
+    const int obj_idx = get_selected_object_idx();
     // is object for simplification selected
-    if (get_selected_object_idx() < 0) return false;
+    // cut object can't be simplify
+    if (obj_idx < 0 || model.objects[obj_idx]->is_cut()) 
+        return false;
+
     // is already opened?
     if (q->canvas3D()->get_gizmos_manager().get_current_type() ==
         GLGizmosManager::EType::Simplify)