E TypeError: Cannot cast array data from dtype('int64') to dtype('int32') according to the rule 'safe'
Tracked it down to incorrect usage of numpy.bincount: This function requires the native index type, which is int32 on i686 (and probably all other 32-bit architectures).
I submitted a documentation change request to numpy: https://github.com/numpy/numpy/issues/23526
I'll try to fix the issue in trimesh and submit an upstream patch.
