[docteurzoidberg]

Fixes #961.

Problem. When a 3MF saved by Snapmaker Orca (or OrcaSlicer / Bambu Studio) is added with the Add button of the Prepare tab, which is the import path with load_config = false, every per-volume setting is wiped. For example, a modifier with sparse_infill_density = 100% falls back to the object's 15 %. Only extruder is kept. Opening the same file with Open project works. Upstream OrcaSlicer keeps these settings with Add.

Debug log when adding the file:

Plater::priv::load_files: load_model 1, load_config 0, input_files size 1
Plater::priv::load_files: is_project_file 0, type_3mf 1
... plate_data.size 1, project_preset.size 0, is_bbs_3mf 1, file_version 2.4.0.0

Cause. In Plater::priv::load_files(), upstream OrcaSlicer handles each En3mfType (From_Orca, From_BBS, From_Other) in its own branch of an if / else if chain. The final else if (!load_config) branch, which resets model_object->config and every model_volume->config except extruder, is therefore never reached for slicer 3MFs. In this fork, those type-specific branches are disabled (else if (false)), so every imported 3MF, including Snapmaker Orca's own (From_BBS), falls through to the reset.

Fix. Skip the reset for From_BBS files, so that adding a slicer 3MF keeps its part/modifier settings as upstream does. Geometry from other applications is still reset.

Testing. I could not build the project locally. The change is a one-line condition. Reproduction file attached to #961.

🤖 Generated with Claude Code

[docteurzoidberg]

Debug log excerpt (Snapmaker Orca 2.4.0, Windows 11, log_severity_level = debug) when adding SNAP_console_centre_manuel.3mf (the project attached to #961) with the Add button. The file contains one modifier with sparse_infill_density = 100%; after loading, it shows the object's 15 %.

01:34:26.117558 UndoRedo::StackImpl::take_snapshot  snapshot name Import Object: SNAP_console_centre_manuel.3mf
01:34:26.120578 Plater::priv::load_files: load_model 1, load_config 0, input_files size 1
01:34:26.161457 Plater::priv::load_files: is_project_file 0, type_3mf 1
01:34:26.197972 load_3mf found metadata key = Application, value = Snapmaker_Orca-2.4.0
01:34:26.213152 _BBS_3MF_Importer::_load_model_from_file:1817 extract 11th file Metadata/model_settings.config, total=13
01:34:26.215152 _BBS_3MF_Importer::_generate_volumes_new: line 4731, subobject_id 1, shared_mesh_id 1
01:34:26.215152 _BBS_3MF_Importer::_generate_volumes_new: line 4731, subobject_id 2, shared_mesh_id 2
01:34:26.220664 Plater::priv::load_files:11653, plate_data.size 1, project_preset.size 0, is_bbs_3mf 1, file_version 2.4.0.0
01:34:26.221924 3MF geometry import filament detection imported_physical=4 ... model_max_extruder=1 ...
01:34:26.221924 3MF geometry import applied imported project config current_num_filaments=4 desired_physical_filaments=4 mixed_enabled=0
01:34:26.306120 Plater::priv::load_files:12391 import 3mf IMPORT_LOAD_MODEL_OBJECTS
01:34:26.363408 LOD: Disabled for 'console_centre'
01:34:26.364412 LOD: Disabled for 'insert'
01:34:26.367424 Plater::priv::load_files:12441, finished load_model_objects

model_settings.config is read and both volumes, the part and the modifier insert, are created. Because load_config is 0 and the file is is_bbs_3mf 1 (From_BBS), the code then reaches the else if (!load_config) reset, which clears the modifier's config except extruder. Opening the same file with File → Open project (load_config 1) keeps the 100 %.