Custom supports data change forces invalidation of supports step

src/libslic3r/Model.cpp

@@ -1948,6 +1948,16 @@ bool model_volume_list_changed(const ModelObject &model_object_old, const ModelO
     return false;
 }
 
+bool model_custom_supports_data_changed(const ModelObject& mo, const ModelObject& mo_new) {
+    assert(! model_volume_list_changed(mo, mo_new, ModelVolumeType::MODEL_PART));
+    assert(mo.volumes.size() == mo_new.volumes.size());
+    for (size_t i=0; i<mo.volumes.size(); ++i) {
+        if (! mo_new.volumes[i]->m_supported_facets.is_same_as(mo.volumes[i]->m_supported_facets))
+            return true;
+    }
+    return false;
+};
+
 extern bool model_has_multi_part_objects(const Model &model)
 {
     for (const ModelObject *model_object : model.objects)

src/libslic3r/Model.hpp

@@ -215,8 +215,8 @@ public:
         when user expects that. */
     Vec3d                   origin_translation;
 
-    Model*                  get_model() { return m_model; };
+    Model*                  get_model() { return m_model; }
-	const Model*            get_model() const { return m_model; };
+    const Model*            get_model() const { return m_model; }
 
     ModelVolume*            add_volume(const TriangleMesh &mesh);
     ModelVolume*            add_volume(TriangleMesh &&mesh);
@@ -402,14 +402,13 @@ class FacetsAnnotation {
 public:
     using ClockType = std::chrono::steady_clock;
 
-
     std::vector<int> get_facets(FacetSupportType type) const;
     void set_facet(int idx, FacetSupportType type);
     void clear();
 
     ClockType::time_point get_timestamp() const { return timestamp; }
-    bool is_newer_than(const FacetsAnnotation& other) const {
+    bool is_same_as(const FacetsAnnotation& other) const {
-        return timestamp > other.get_timestamp();
+        return timestamp == other.get_timestamp();
     }
 
 private:
@@ -455,7 +454,7 @@ public:
     FacetsAnnotation    m_supported_facets;
 
     // A parent object owning this modifier volume.
-    ModelObject*        get_object() const { return this->object; };
+    ModelObject*        get_object() const { return this->object; }
     ModelVolumeType     type() const { return m_type; }
     void                set_type(const ModelVolumeType t) { m_type = t; }
 	bool                is_model_part()         const { return m_type == ModelVolumeType::MODEL_PART; }
@@ -859,7 +858,7 @@ public:
     std::string   propose_export_file_name_and_path(const std::string &new_extension) const;
 
 private:
-	explicit Model(int) : ObjectBase(-1) { assert(this->id().invalid()); };
+    explicit Model(int) : ObjectBase(-1) { assert(this->id().invalid()); }
 	void assign_new_unique_ids_recursive();
 	void update_links_bottom_up_recursive();
 
@@ -886,6 +885,10 @@ extern bool model_object_list_extended(const Model &model_old, const Model &mode
 // than the old ModelObject.
 extern bool model_volume_list_changed(const ModelObject &model_object_old, const ModelObject &model_object_new, const ModelVolumeType type);
 
+// Test whether the now ModelObject has newer custom supports data than the old one.
+// The function assumes that volumes list is synchronized.
+extern bool model_custom_supports_data_changed(const ModelObject& mo, const ModelObject& mo_new);
+
 // If the model has multi-part objects, then it is currently not supported by the SLA mode.
 // Either the model cannot be loaded, or a SLA printer has to be activated.
 extern bool model_has_multi_part_objects(const Model &model);

src/libslic3r/Print.cpp

@@ -855,7 +855,7 @@ Print::ApplyStatus Print::apply(const Model &model, DynamicPrintConfig new_full_
             }
             // Copy content of the ModelObject including its ID, do not change the parent.
             model_object.assign_copy(model_object_new);
-        } else if (support_blockers_differ || support_enforcers_differ) {
+        } else if (support_blockers_differ || support_enforcers_differ || model_custom_supports_data_changed(model_object, model_object_new)) {
             // First stop background processing before shuffling or deleting the ModelVolumes in the ModelObject's list.
             this->call_cancel_callback();
             update_apply_status(false);
@@ -863,9 +863,11 @@ Print::ApplyStatus Print::apply(const Model &model, DynamicPrintConfig new_full_
             auto range = print_object_status.equal_range(PrintObjectStatus(model_object.id()));
             for (auto it = range.first; it != range.second; ++ it)
                 update_apply_status(it->print_object->invalidate_step(posSupportMaterial));
+            if (support_enforcers_differ || support_blockers_differ) {
                 // Copy just the support volumes.
                 model_volume_list_update_supports(model_object, model_object_new);
             }
+        }
         if (! model_parts_differ && ! modifiers_differ) {
             // Synchronize Object's config.
             bool object_config_changed = model_object.config != model_object_new.config;