Programmatically generating box UVW maps

Question

I'm need to programmatically generate box UVW maps in 3D-models, similar to how UVW Map -> Box works in 3ds Max.

Example with default UV

Example with box UV, what I'm after

I've tried javascript-based solutions such as this or this, but it seems to give various results depending on if the mesh/geometry is merged or if it already has any built in UV. Or it has different directions.

Applying box UV-map via Blender or 3ds Max to the same 3D-model always gives perfect results though.

Best case scenario would be a command line tool, similar to how gltf-pipeline works:

generate-box-map -i model.gltf -type box -size 50

I've found tools/projects such as PyMeshLab, Meshmatic, or running a Blender instance and attempting to do it via python, but I couldn't find a solution. Perhaps there's a native/easier way of doing this?

Answer 1

I ended up solving this in Blender through Docker via this image https://github.com/linuxserver/docker-blender.

The project structure is

app.js

Receives a request via express, body contains https://some-storage.com/model.gltf and starts a Blender process via child_process.exec(`blender -b --addons magic_uv -P /app/src/main.py --log-level -1 -- ${pathToDownloadedGLTFFile}`)

main.py

...

    argv = sys.argv
    argv = argv[argv.index("--") + 1:]  # get all args after "--"

    param_input_file = argv[0]

    bpy.ops.import_scene.gltf(filepath=param_input_file)
    for obj in bpy.data.objects:
        if obj.type == 'MESH':
            obj.select_set(True) # select the object
            bpy.context.view_layer.objects.active = obj # needed to enable Edit mode below
            bpy.ops.object.mode_set(mode='EDIT')

    bpy.ops.uv.muv_uvw_box_map(size=instructions['size'], rotation=(instructions['rotationX'], instructions['rotationY'], instructions['rotationZ']))

...

# export back to GLTF and write to /some/dir/model.gltf

Regarding the problem with different directions of UV, setting rotation.x to 270 seems to fix it.