trimesh/grouping.py:59: IndexError

[gleb-an]

I got this error when I execute mesh.merge_vertices() or mesh.process() with the trimesh==3.9.20

        if hasattr(mesh, 'faces') and len(mesh.faces) > 0:
            referenced = np.zeros(len(mesh.vertices), dtype=bool)
>           referenced[mesh.faces] = True
E           IndexError: index 29 is out of bounds for axis 0 with size 28

../venv/lib/python3.8/site-packages/trimesh/grouping.py:59: IndexError

The same error I got with the 3.9.10 version.

This code works with the 3.9.1 version!

Python 3.8 OS Ubuntu 20.04

[mikedh]

Hey, is the mesh referencing vertices that don't exist? For example I can reproduce with:

    mesh = trimesh.Trimesh(vertices=[], faces=[[0,1,2]])
    mesh.merge_vertices()

Where faces reference vertices that aren't there. I added an early exit for the case where len(mesh.vertices) == 0 but in the wider case (faces reference non-existent vertices) I think raising an IndexError is probably the right thing to do.

[gleb-an]

I have arrays like this(attached) faces.txt vertices.txt

[gleb-an]

any updates on this?