# Known issues and limitations
Listed below are the current known limitations and issues. They can be there for compatibility reasons between Simplygon, Blender and GLTF, workarounds or in some cases just bugs somewhere in the pipeline.
# General issues
- When running a long process and the user is performing other tasks, the add-on will still import as soon as the processing is over, potentially interrupting something else.
- Running a python script mid-processing causes Blender to forget that the processing is happening and the output is never imported back.
# Scene inconsistencies
- Since the meshes go through the GLTF exporter and importer certain geometry fields, material types, or other scene contents may disappear or be modified after processing.
- Scene node hierarchy may also be modified.
- Skinned meshes may behave strangely if they have transforms applied to the skeleton root.
# Missing functionality
- All functionality that depend on selection sets are currently disabled. These include:
- ProcessSelectionSet
- ClippingGeometry
- Etc.
- Custom cameras for visibility culling
- Clipping planes
# Materials
- Since the meshes go through the GLTF exporter and importer, the material channels that are possible to setup for casting are limited to those supported by the blender GLTF exporter.