From 5ec84adb14a9c19f0af64feefa4da79f655b4c23 Mon Sep 17 00:00:00 2001
From: YuSanka <yusanka@gmail.com>
Date: Wed, 17 Aug 2022 09:58:20 +0200
Subject: [PATCH] Cut WIP: Add only needed modifiers

---
 src/libslic3r/Model.cpp              | 14 +++++++-------
 src/slic3r/GUI/GUI_ObjectList.cpp    |  3 ++-
 src/slic3r/GUI/Gizmos/GLGizmoCut.hpp |  2 +-
 3 files changed, 10 insertions(+), 9 deletions(-)

diff --git a/src/libslic3r/Model.cpp b/src/libslic3r/Model.cpp
index ffa74f79c..293d31eae 100644
--- a/src/libslic3r/Model.cpp
+++ b/src/libslic3r/Model.cpp
@@ -1380,10 +1380,6 @@ indexed_triangle_set ModelObject::get_connector_mesh(CutConnectorAttributes conn
 
 void ModelObject::apply_cut_connectors(const std::string& name)
 {
-    // discard old connector markers for volumes
-    for (ModelVolume* volume : volumes)
-        volume->cut_info.discard();
-
     if (cut_connectors.empty())
         return;
 
@@ -1517,6 +1513,8 @@ ModelObjectPtrs ModelObject::cut(size_t instance, const Vec3d& cut_center, const
 
         if (!volume->is_model_part()) {
             if (volume->cut_info.is_connector) {
+                volume->cut_info.discard();
+
                 // ! Don't apply instance transformation for the conntectors.
                 // This transformation is already there
                 if (attributes.has(ModelObjectCutAttribute::KeepUpper)) {
@@ -1559,10 +1557,12 @@ ModelObjectPtrs ModelObject::cut(size_t instance, const Vec3d& cut_center, const
                 // to the modifier volume transformation to preserve their shape properly.
                 volume->set_transformation(Geometry::Transformation(instance_matrix * volume_matrix));
 
-                // #ysFIXME - add logic for the negative volumes/connectors
-                if (attributes.has(ModelObjectCutAttribute::KeepUpper))
+                // Some logic for the negative volumes/connectors. Add only needed modifiers
+                auto bb = volume->mesh().transformed_bounding_box(cut_matrix * volume->get_matrix());
+                bool is_crossed_by_cut = bb.min[Z] <= 0 && bb.max[Z] >= 0;
+                if (attributes.has(ModelObjectCutAttribute::KeepUpper) && (bb.min[Z] >= 0 || is_crossed_by_cut))
                     upper->add_volume(*volume);
-                if (attributes.has(ModelObjectCutAttribute::KeepLower))
+                if (attributes.has(ModelObjectCutAttribute::KeepLower) && (bb.max[Z] <= 0 || is_crossed_by_cut))
                     lower->add_volume(*volume);
             }
         }
diff --git a/src/slic3r/GUI/GUI_ObjectList.cpp b/src/slic3r/GUI/GUI_ObjectList.cpp
index cc6954665..769b038fa 100644
--- a/src/slic3r/GUI/GUI_ObjectList.cpp
+++ b/src/slic3r/GUI/GUI_ObjectList.cpp
@@ -2918,6 +2918,7 @@ bool ObjectList::delete_from_model_and_list(const ItemType type, const int obj_i
                     update_lock_icons_for_model();
                 return true;
             }
+            return false;
         }
         else if (del_subobject_from_object(obj_idx, sub_obj_idx, type)) {
             type == itVolume ? delete_volume_from_list(obj_idx, sub_obj_idx) :
@@ -2942,7 +2943,7 @@ bool ObjectList::delete_from_model_and_list(const std::vector<ItemForDelete>& it
         if (item->type&itObject) {
             bool was_cut = object(item->obj_idx)->is_cut();
             if (!del_object(item->obj_idx))
-                continue;
+                return false;// continue;
             m_objects_model->Delete(m_objects_model->GetItemById(item->obj_idx));
             if (was_cut)
                 update_lock_icons_for_model();
diff --git a/src/slic3r/GUI/Gizmos/GLGizmoCut.hpp b/src/slic3r/GUI/Gizmos/GLGizmoCut.hpp
index 1665b8549..f8f788138 100644
--- a/src/slic3r/GUI/Gizmos/GLGizmoCut.hpp
+++ b/src/slic3r/GUI/Gizmos/GLGizmoCut.hpp
@@ -77,7 +77,7 @@ class GLGizmoCut3D : public GLGizmoBase
     bool m_keep_upper{ true };
     bool m_keep_lower{ true };
     bool m_place_on_cut_upper{ true };
-    bool m_place_on_cut_lower{ true };
+    bool m_place_on_cut_lower{ false };
     bool m_rotate_upper{ false };
     bool m_rotate_lower{ false };