Fix instance Z synchronization (#15465)

src/libslic3r/Format/bbs_3mf.cpp

@@ -987,6 +987,7 @@ void PlateData::parse_filament_info(GCodeProcessorResult *result)
 
             MetadataList metadata;
             VolumeMetadataList volumes;
+            bool auto_drop { true };
         };
 
         struct CutObjectInfo
@@ -1367,7 +1368,7 @@ void PlateData::parse_filament_info(GCodeProcessorResult *result)
         bool _handle_start_text_configuration(const char** attributes, unsigned int num_attributes);
         bool _handle_start_shape_configuration(const char **attributes, unsigned int num_attributes);
 
-        bool _create_object_instance(std::string const & path, int object_id, const Transform3d& transform, const bool printable, const bool auto_drop, unsigned int recur_counter);
+        bool _create_object_instance(std::string const & path, int object_id, const Transform3d& transform, const bool printable, unsigned int recur_counter);
 
         void _apply_transform(ModelInstance& instance, const Transform3d& transform);
 
@@ -2259,6 +2260,8 @@ void PlateData::parse_filament_info(GCodeProcessorResult *result)
             if (obj_metadata != m_objects_metadata.end()) {
                 // config data has been found, this model was saved using slic3r pe
 
+                model_object->auto_drop = obj_metadata->second.auto_drop;
+
                 // apply object's name and config data
                 for (const Metadata& metadata : obj_metadata->second.metadata) {
                     if (metadata.key == "name")
@@ -4117,9 +4120,7 @@ void PlateData::parse_filament_info(GCodeProcessorResult *result)
         std::string path = bbs_get_attribute_value_string(attributes, num_attributes, PPATH_ATTR);
         Transform3d transform = bbs_get_transform_from_3mf_specs_string(bbs_get_attribute_value_string(attributes, num_attributes, TRANSFORM_ATTR));
         int printable = bbs_get_attribute_value_bool(attributes, num_attributes, PRINTABLE_ATTR);
-        int auto_drop = bbs_get_attribute_value_bool(attributes, num_attributes, AUTO_DROP_ATTR);
-
-        return !m_load_model || _create_object_instance(path, object_id, transform, printable, auto_drop, 1);
+        return !m_load_model || _create_object_instance(path, object_id, transform, printable, 1);
     }
 
     bool _BBS_3MF_Importer::_handle_end_item()
@@ -4347,7 +4348,7 @@ void PlateData::parse_filament_info(GCodeProcessorResult *result)
         return true;
     }
 
-    bool _BBS_3MF_Importer::_create_object_instance(std::string const & path, int object_id, const Transform3d& transform, const bool printable, const bool auto_drop, unsigned int recur_counter)
+    bool _BBS_3MF_Importer::_create_object_instance(std::string const & path, int object_id, const Transform3d& transform, const bool printable, unsigned int recur_counter)
     {
         static const unsigned int MAX_RECURSIONS = 10;
 
@@ -4384,7 +4385,6 @@ void PlateData::parse_filament_info(GCodeProcessorResult *result)
                 return false;
             }
             instance->printable = printable;
-            instance->auto_drop = auto_drop;    
 
             m_instances.emplace_back(instance, transform);
 
@@ -4417,7 +4417,6 @@ void PlateData::parse_filament_info(GCodeProcessorResult *result)
                 return false;
             }
             instance->printable = printable;
-            instance->auto_drop = auto_drop;    
 
             m_instances.emplace_back(instance, transform);
         }
@@ -4488,7 +4487,9 @@ void PlateData::parse_filament_info(GCodeProcessorResult *result)
         // Added because of github #3435, currently not used by PrusaSlicer
         // int instances_count_id = bbs_get_attribute_value_int(attributes, num_attributes, INSTANCESCOUNT_ATTR);
 
-        m_objects_metadata.insert({ object_id, ObjectMetadata() });
+        ObjectMetadata metadata;
+        metadata.auto_drop = bbs_get_attribute_value_bool(attributes, num_attributes, AUTO_DROP_ATTR);
+        m_objects_metadata.insert({ object_id, std::move(metadata) });
         m_curr_config.object_id = object_id;
         return true;
     }
@@ -6164,14 +6165,12 @@ void PlateData::parse_filament_info(GCodeProcessorResult *result)
             unsigned int id;
             Transform3d transform;
             bool printable;
-            bool auto_drop;
 
-            BuildItem(std::string const & path, unsigned int id, const Transform3d& transform, const bool printable, const bool auto_drop)
+            BuildItem(std::string const & path, unsigned int id, const Transform3d& transform, const bool printable)
                 : path(path)
                 , id(id)
                 , transform(transform)
                 , printable(printable)
-                , auto_drop(auto_drop)
             {
             }
         };
@@ -7412,7 +7411,7 @@ void PlateData::parse_filament_info(GCodeProcessorResult *result)
                     // instance_id is just a 1 indexed index in build_items.
                     //assert(m_skip_static || curr_id == build_items.size() + 1);
 
-                    build_items.emplace_back("", object_it->second.object_id, t, instance->printable, instance->auto_drop);
+                    build_items.emplace_back("", object_it->second.object_id, t, instance->printable);
                     count++;
                 }
 
@@ -7862,8 +7861,7 @@ void PlateData::parse_filament_info(GCodeProcessorResult *result)
                 stream << "\" " << PPATH_ATTR << "=\"" << xml_escape(item.path);
             stream << "\" " << TRANSFORM_ATTR << "=\"";
             add_transformation(stream, item.transform);
-            stream << "\" " << PRINTABLE_ATTR << "=\"" << item.printable;
-            stream << "\" " << AUTO_DROP_ATTR << "=\"" << item.auto_drop << "\"/>\n";
+            stream << "\" " << PRINTABLE_ATTR << "=\"" << item.printable << "\"/>\n";
         }
 
         stream << " </" << BUILD_TAG << ">\n";
@@ -8300,7 +8298,8 @@ bool _BBS_3MF_Exporter::_add_model_config_file_to_archive(mz_zip_archive& archiv
             if (obj != nullptr) {
                 // Output of instances count added because of github #3435, currently not used by PrusaSlicer
                 //stream << "  <"  << OBJECT_TAG << " " << ID_ATTR << "=\"" << obj_metadata.first << "\" " << INSTANCESCOUNT_ATTR << "=\"" << obj->instances.size() << "\">\n";
-                stream << "  <" << OBJECT_TAG << " " << ID_ATTR << "=\"" << object_data.object_id << "\">\n";
+                stream << "  <" << OBJECT_TAG << " " << ID_ATTR << "=\"" << object_data.object_id
+                       << "\" " << AUTO_DROP_ATTR << "=\"" << obj->auto_drop << "\">\n";
 
                 // stores object's name
                 if (!obj->name.empty())

src/libslic3r/Model.cpp

@@ -1280,6 +1280,7 @@ ModelObject& ModelObject::assign_copy(const ModelObject &rhs)
     this->layer_config_ranges         = rhs.layer_config_ranges;
     this->layer_height_profile        = rhs.layer_height_profile;
     this->printable                   = rhs.printable;
+    this->auto_drop                   = rhs.auto_drop;
     this->origin_translation          = rhs.origin_translation;
     this->cut_id.copy(rhs.cut_id);
     this->copy_transformation_caches(rhs);
@@ -1320,6 +1321,7 @@ ModelObject& ModelObject::assign_copy(ModelObject &&rhs)
     this->layer_config_ranges         = std::move(rhs.layer_config_ranges);
     this->layer_height_profile        = std::move(rhs.layer_height_profile);
     this->printable                   = std::move(rhs.printable);
+    this->auto_drop                   = rhs.auto_drop;
     this->origin_translation          = std::move(rhs.origin_translation);
     this->copy_transformation_caches(rhs);
 
@@ -1889,6 +1891,9 @@ void ModelObject::center_around_origin(bool include_modifiers)
 
 void ModelObject::ensure_on_bed(bool allow_negative_z)
 {
+    if (!auto_drop)
+        return;
+
     double z_offset = 0.0;
 
     if (allow_negative_z) {
@@ -1907,14 +1912,8 @@ void ModelObject::ensure_on_bed(bool allow_negative_z)
     else
         z_offset = -this->min_z();
 
-    if (z_offset != 0.0) {
-        for (size_t i = 0; i < instances.size(); ++i) {
-            if (!instances[i]->auto_drop)
-                continue;
-
-            translate_instance(i, z_offset * Vec3d::UnitZ());
-        }
-    }
+    if (z_offset != 0.0)
+        translate_instances(z_offset * Vec3d::UnitZ());
 }
 
 void ModelObject::translate_instances(const Vec3d& vector)

src/libslic3r/Model.hpp

@@ -400,6 +400,9 @@ public:
     LayerHeightProfile      layer_height_profile;
     // Whether or not this object is printable
     bool                    printable { true };
+    // Whether this object is snapped to the build plate after transformations.
+    // Instance Z offsets are shared by all instances of an object.
+    bool                    auto_drop { true };
 
     // This vector holds position of selected support points for SLA. The data are
     // saved in mesh coordinates to allow using them for several instances.
@@ -706,7 +709,7 @@ private:
         Internal::StaticSerializationWrapper<ModelConfigObject const> config_wrapper(config);
         Internal::StaticSerializationWrapper<LayerHeightProfile const> layer_heigth_profile_wrapper(layer_height_profile);
         ar(name, module_name, input_file, instances, volumes, config_wrapper, layer_config_ranges, layer_heigth_profile_wrapper,
-            sla_support_points, sla_points_status, sla_drain_holes, printable, origin_translation, brim_points,
+            sla_support_points, sla_points_status, sla_drain_holes, printable, auto_drop, origin_translation, brim_points,
             m_bounding_box_approx, m_bounding_box_approx_valid, 
             m_bounding_box_exact, m_bounding_box_exact_valid, m_min_max_z_valid,
             m_raw_bounding_box, m_raw_bounding_box_valid, m_raw_mesh_bounding_box, m_raw_mesh_bounding_box_valid,
@@ -719,7 +722,7 @@ private:
         // BBS: add backup, check modify
         SaveObjectGaurd gaurd(*this);
         ar(name, module_name, input_file, instances, volumes, config_wrapper, layer_config_ranges, layer_heigth_profile_wrapper,
-            sla_support_points, sla_points_status, sla_drain_holes, printable, origin_translation, brim_points,
+            sla_support_points, sla_points_status, sla_drain_holes, printable, auto_drop, origin_translation, brim_points,
             m_bounding_box_approx, m_bounding_box_approx_valid, 
             m_bounding_box_exact, m_bounding_box_exact_valid, m_min_max_z_valid,
             m_raw_bounding_box, m_raw_bounding_box_valid, m_raw_mesh_bounding_box, m_raw_mesh_bounding_box_valid,
@@ -1427,7 +1430,6 @@ public:
     ModelInstanceEPrintVolumeState print_volume_state;
     // Whether or not this instance is printable
     bool printable;
-    bool auto_drop;
     bool use_loaded_id_for_label {false};
     int arrange_order = 0; // BBS
     size_t loaded_id = 0; // BBS
@@ -1557,7 +1559,7 @@ private:
 
     // Constructor, which assigns a new unique ID.
     explicit ModelInstance(ModelObject* object)
-        : print_volume_state(ModelInstancePVS_Inside), printable(true), auto_drop(true), object(object), m_assemble_initialized(false)
+        : print_volume_state(ModelInstancePVS_Inside), printable(true), object(object), m_assemble_initialized(false)
     {
         assert(this->id().valid());
     }
@@ -1568,7 +1570,6 @@ private:
         , m_offset_to_assembly(other.m_offset_to_assembly)
         , print_volume_state(ModelInstancePVS_Inside)
         , printable(other.printable)
-        , auto_drop(other.auto_drop)
         , object(object)
         , m_assemble_initialized(false) { assert(this->id().valid() && this->id() != other.id()); }
 
@@ -1582,7 +1583,7 @@ private:
 	ModelInstance() : ObjectBase(-1), object(nullptr) { assert(this->id().invalid()); }
     // BBS. Add added members to archive.
     template<class Archive> void serialize(Archive& ar) {
-        ar(m_transformation, print_volume_state, printable, auto_drop, m_assemble_transformation, m_offset_to_assembly, m_assemble_initialized);
+        ar(m_transformation, print_volume_state, printable, m_assemble_transformation, m_offset_to_assembly, m_assemble_initialized);
     }
 };
 

src/slic3r/GUI/GLCanvas3D.cpp

@@ -3053,10 +3053,9 @@ void GLCanvas3D::ensure_on_bed(unsigned int object_idx, bool allow_negative_z)
     InstancesToZMap instances_min_z;
 
     for (GLVolume* volume : m_volumes.volumes) {
-        ModelObject*   mo = m_model->objects[volume->object_idx()];
-        ModelInstance* mi = mo->instances[volume->instance_idx()];
+        ModelObject* mo = m_model->objects[volume->object_idx()];
 
-        if (!mi->auto_drop) {
+        if (!mo->auto_drop) {
             continue;
         }
 
@@ -5604,9 +5603,8 @@ void GLCanvas3D::do_move(const std::string& snapshot_type)
     // Fixes sinking/flying instances (snaps object to buildplate)
     for (const std::pair<int, int>& i : done) {
         ModelObject* mo = m_model->objects[i.first];
-        ModelInstance* mi  = mo->instances[i.second];
             
-        if (!mi->auto_drop) {
+        if (!mo->auto_drop) {
             continue;
         }
 
@@ -5735,9 +5733,8 @@ void GLCanvas3D::do_rotate(const std::string& snapshot_type)
         // Fixes sinking/flying instances (snaps object to buildplate)
         for (const std::pair<int, int> &i : done) {
             ModelObject *mo = m_model->objects[i.first];
-            ModelInstance* mi = mo->instances[i.second];
 
-            if (!mi->auto_drop) {
+            if (!mo->auto_drop) {
                 continue;
             }
 
@@ -5838,9 +5835,8 @@ void GLCanvas3D::do_scale(const std::string& snapshot_type)
     // Fixes sinking/flying instances (snaps object to buildplate)
     for (const std::pair<int, int>& i : done) {
         ModelObject* mo = m_model->objects[i.first];
-        ModelInstance* mi = mo->instances[i.second];
 
-        if (!mi->auto_drop) {
+        if (!mo->auto_drop) {
             continue;
         }
 
@@ -5959,9 +5955,8 @@ void GLCanvas3D::do_mirror(const std::string& snapshot_type)
     // Fixes sinking/flying instances (snaps object to buildplate)
     for (const std::pair<int, int>& i : done) {
         ModelObject* mo = m_model->objects[i.first];
-        ModelInstance* mi = mo->instances[i.second];
 
-        if (!mi->auto_drop) {
+        if (!mo->auto_drop) {
             continue;
         }
 

src/slic3r/GUI/GUI_ObjectList.cpp

@@ -3234,8 +3234,8 @@ void ObjectList::merge(bool to_multipart_object)
                 new_object->printable = false;
                 new_object->instances[0]->printable = false;
             }
-            if (object->instances[0]->auto_drop == false) {
-                new_object->instances[0]->auto_drop = false;
+            if (object->auto_drop == false) {
+                new_object->auto_drop = false;
             }
 
             // merge layers
@@ -7098,18 +7098,10 @@ void ObjectList::toggle_auto_drop()
 
         obj_idxs.emplace_back(static_cast<size_t>(obj_idx));
 
-        ItemType type = m_objects_model->GetItemType(item);
-        // set auto_drop value for selected instance/instances in object
-        if (type == itInstance) {
-            int inst_idx = m_objects_model->GetInstanceIdByItem(item);
-            obj->instances[inst_idx]->auto_drop = !current_auto_drop;
-        } else {
-            for (auto inst : obj->instances)
-                inst->auto_drop = !current_auto_drop;
-                
-        if (current_auto_drop == false) 
+        // auto_drop is shared by all instances of an object.
+        obj->auto_drop = !current_auto_drop;
+        if (current_auto_drop == false)
             obj->ensure_on_bed();
-        }
     }
 
     sort(obj_idxs.begin(), obj_idxs.end());

src/slic3r/GUI/Plater.cpp

@@ -10359,10 +10359,7 @@ std::vector<size_t> Plater::priv::load_model_objects(const ModelObjectPtrs& mode
         }
 
         if (!auto_drop) {
-            for (size_t i = 0; i < object->instances.size(); ++i) {
-                ModelInstance* instance  = object->instances[i];
-                instance->auto_drop = auto_drop;
-            }
+            object->auto_drop = false;
 
             // if under the bed, move over the bed
             double dist_to_bed = std::min(object->min_z(), double(0));
@@ -10991,7 +10988,7 @@ void Plater::priv::split_object(int obj_idx, bool auto_drop /* = true */)
             return false;
         };
         bool split_auto_drop = auto_drop;
-        if (current_model_object->instances[0]->auto_drop && is_atleast_one_floating()) {
+        if (current_model_object->auto_drop && is_atleast_one_floating()) {
             MessageDialog dlg(q, _L("Disable Auto-Drop to preserve Z positioning?\n"),
                                   _L("Object with floating parts was detected"), wxICON_QUESTION | wxYES_NO);
 

src/slic3r/GUI/Selection.cpp

@@ -638,26 +638,21 @@ void Selection::set_printable(bool printable)
 }
 
 bool Selection::get_auto_drop() const {
-    // The wipe tower is not a ModelObject and has no per-instance auto_drop;
+    // The wipe tower is not a ModelObject and has no auto_drop state;
     // return the default to avoid indexing m_model->objects with its synthetic id.
     if (!m_valid || is_wipe_tower())
         return true;
 
-    std::set<std::pair<int, int>> instances_idxs;
+    std::set<int> object_idxs;
     for (const auto& [obj_idx, inst_list] : m_cache.content) {
-        for (int inst_idx : inst_list) {
-            instances_idxs.insert({obj_idx, inst_idx});
-        }
+        object_idxs.insert(obj_idx);
     }
 
-    // return false, if one of the instances in the selection has auto_drop disabled, otherwise return true
-    for (const auto& [obj_idx, inst_idx] : instances_idxs) {
+    // Return false if one selected object has auto_drop disabled.
+    for (int obj_idx : object_idxs) {
         ModelObject* object = m_model->objects[obj_idx];
-        for (const auto* inst : object->instances) {
-            if (!inst->auto_drop) {
-                return false;
-            }
-        }
+        if (!object->auto_drop)
+            return false;
     }
 
     return true;
@@ -668,22 +663,18 @@ void Selection::set_auto_drop(bool enabled)
     if (!m_valid)
         return;
 
-    std::set<std::pair<int, int>> instances_idxs;
+    std::set<int> object_idxs;
     for (const auto& [obj_idx, inst_list] : m_cache.content) {
-        for (int inst_idx : inst_list) {
-            instances_idxs.insert({obj_idx, inst_idx});
-        }
+        object_idxs.insert(obj_idx);
     }
 
     std::string snapshot_text = (boost::format("%1%") % (enabled ? "Set Selection Auto-Drop Enabled" : "Set Selection Auto-Drop Disabled")).str();
     wxGetApp().plater()->take_snapshot(snapshot_text);
 
-    // set auto_drop value for all instances in object
-    for (const auto& [obj_idx, inst_idx] : instances_idxs) {
+    // auto_drop is shared by all instances of an object.
+    for (int obj_idx : object_idxs) {
         ModelObject* object = m_model->objects[obj_idx];
-        for (auto* inst : object->instances) {
-            inst->auto_drop = enabled;
-        }
+        object->auto_drop = enabled;
     }
 
     // update scene
@@ -3088,8 +3079,9 @@ void Selection::synchronize_unselected_instances(SyncRotationType sync_rotation_
             else if (sync_rotation_type != SyncRotationType::NONE || mirrored)
                 new_inst_trafo_j.linear() = (old_inst_trafo_j.linear() * old_inst_trafo_i.linear().inverse()) * curr_inst_trafo_i.linear();
 
-            bool should_synchronize_z = m_model->objects[volume_j->object_idx()]->instances[volume_j->instance_idx()]->auto_drop == false;
-            if (should_synchronize_z && wxGetApp().preset_bundle->printers.get_edited_preset().printer_technology() != ptSLA)
+            // Instances of the same object must remain at the same height. auto_drop
+            // only controls snapping after the move, not the instance transform itself.
+            if (wxGetApp().preset_bundle->printers.get_edited_preset().printer_technology() != ptSLA)
                 new_inst_trafo_j.translation().z() = curr_inst_trafo_i.translation().z();
 
             assert(is_rotation_xy_synchronized(curr_inst_trafo_i, new_inst_trafo_j));
@@ -3136,9 +3128,7 @@ void Selection::ensure_on_bed()
     for (size_t i = 0; i < m_volumes->size(); ++i) {
         GLVolume* volume    = (*m_volumes)[i];
         ModelObject*   mo   = m_model->objects[volume->object_idx()];
-        ModelInstance* mi   = mo->instances[volume->instance_idx()];
-
-        if (mi->auto_drop == false
+        if (mo->auto_drop == false
             || volume->is_wipe_tower 
             || volume->is_modifier 
             || std::find(m_cache.sinking_volumes.begin(), m_cache.sinking_volumes.end(), i) != m_cache.sinking_volumes.end())