Fix/forward kwargs

[michaelbratsch]

With the pull-request #2241, load_mesh does not respect the parameter process anymore.

With this pull-request, the kwargs are being forwarded in load_stl.

[michaelbratsch]

The fix of this pull-request seems to cause a regression in the existing unit tests:

trimesh/tests/test_stl.py

Line 18 in aed7eee

assert len(m.metadata["header"]) > 0

@mikedh What is the supposed way in the current design to forward the kwargs?

[mikedh]

Thanks for the fix and great test! I think we have to do this in load_scene to replicate the old behavior, this needs some work but passes your test: 907d7dd

[michaelbratsch]

Thank you for your quick reply and immediately taking care of it ❤️

I am also wondering about a related issue which is not being fixed with the current pull-request. I put the questions along with this example that way it is probably easiest to see. If wanted, I can open a proper issue for it.

import trimesh

file_name = "models/featuretype.stl"

with open(file_name, "rb") as fh:
    mesh = trimesh.load_mesh(file_obj=fh, file_type="stl", process=False)

    assert len(mesh.faces) == 3476
    assert len(mesh.vertices) == 10428

with open(file_name, "rb") as fh:
    mesh = trimesh.load_mesh(file_obj=fh, file_type="stl", process=True)
    
    # Why is only the number of vertices being reduced but not the number of faces?
    assert len(mesh.faces) == 3476
    assert len(mesh.vertices) == 1722
    
    mesh.export('./mesh_test.stl')

with open('./mesh_test.stl', 'rb') as fh:
    mesh = trimesh.load_mesh(file_obj=fh, file_type="stl", process=False)
    
    assert len(mesh.faces) == 3476
    # Why is the number of vertices again 10428 even though it is from the exported reduced model?
    assert len(mesh.vertices) == 10428

[mikedh]

No worries! I'm going to check whether we have the same bug in the other load entrypoints before merging.

Why is the number of vertices again 10428 even though it is from the exported reduced model?

That's actually because STL just outputs a "bundle of triangles" with no indexes (hence the need for the vertex merging on load, since trimesh started as just an STL loader haha). If you use a format with indexes (OFF, OBJ*, GLB, PLY, etc) it should pass as you expect:

    mesh.export('./mesh_test.off')

    with open('./mesh_test.off', 'rb') as fh:
        mesh = trimesh.load_mesh(file_obj=fh, file_type="off", process=False)
        assert len(mesh.faces) == 3476                                                       
        assert len(mesh.vertices) == 1722

[michaelbratsch]

All right, got it. Thanks for the explanation.