I think the loader is failing silently near the end of setInstructionsLook():

def setupInstructionsLook():
    # ...

    # This line is failing with:
    #     AttributeError: 'RenderSettings' object has no attribute 'alpha_mode'
    #
    # This attribute doesn't appear in the latest 3.5 docs:
    #     https://docs.blender.org/api/current/bpy.types.RenderSettings.html
    render.alpha_mode = 'TRANSPARENT'

    # ...

I noticed this when running Blender from the terminal:

# launch and run the import via Blender File -> Import
/Applications/Blender.app/Contents/MacOS/Blender

# launch script to automatically render a brick
/Applications/Blender.app/Contents/MacOS/Blender --background --python my-script-to-render-lego.py

Move evidence: the add-on continues to work if I change the offending line to an early return and use the importer normally via Blender File -> Import

Is the rest of setupInstructionsLook() needed? If not would you be open to a PR? I am building a script to render parts and it fails here. Update: I noticed it is missing white lines on black parts

Details:

• Blender Version 3.5.0 (3.5.0 2023-03-29)
• MacOS 13.3.1 (22E261)