KeyError while loading PR2 description

[stephane-caron]

trafficstars

• yourdfpy version 0.0.52

A KeyError pops out when trying to open the pr2_simplified.urdf description from Drake:

$ yourdfpy examples/pr2/models/pr2_description/urdf/pr2_simplified.urdf                                                                                           ✔ 
Traceback (most recent call last):
  File "~/.local/bin/yourdfpy", line 8, in <module>
    sys.exit(run())
  File "~/.local/lib/python3.8/site-packages/yourdfpy/viz.py", line 198, in run
    main(sys.argv[1:])
  File "~/.local/lib/python3.8/site-packages/yourdfpy/viz.py", line 187, in main
    urdf_model.show(
  File "~/.local/lib/python3.8/site-packages/yourdfpy/urdf.py", line 859, in show
    elif len(self._scene.bounds_corners) < 1:
  File "~/.local/lib/python3.8/site-packages/trimesh/caching.py", line 109, in get_cached
    value = function(*args, **kwargs)
  File "~/.local/lib/python3.8/site-packages/trimesh/scene/scene.py", line 330, in bounds_corners
    transform, geometry_name = self.graph[node_name]
  File "~/.local/lib/python3.8/site-packages/trimesh/scene/transforms.py", line 471, in __getitem__
    return self.get(key)
  File "~/.local/lib/python3.8/site-packages/trimesh/scene/transforms.py", line 145, in get
    matrices = [edge_data[(u, v)]['matrix'] for u, v in
  File "~/.local/lib/python3.8/site-packages/trimesh/scene/transforms.py", line 145, in <listcomp>
    matrices = [edge_data[(u, v)]['matrix'] for u, v in
KeyError: 'matrix'

(The model from the git repository tries to load .obj meshes, while they are in fact .stl. This error remains even after replacing all occurrences of .obj by .stl in the file.)