UsdGeom.Mesh(mesh_prim).GetPointsAttr().Get() returns 0 length mesh in

I am observing the following error when running with a custom object.
This is based on: 6. Offline Pose Estimation Synthetic Data Generation — Omniverse Robotics documentation

Traceback (most recent call last):
File “./”, line 664, in
File “./”, line 155, in init
File “./”, line 366, in _setup_world
self.writer_helper.save_mesh_vertices(mesh_prim, coord_prim, prim_type, self._output_folder)
File “/data/omniverse/library/isaac_sim-2022.2.0/exts/omni.replicator.isaac/omni/replicator/isaac/scripts/writers/”, line 184, in save_mesh_vertices
points = get_mesh_vertices_relative_to(mesh_prim, coord_prim)
File “/data/omniverse/library/isaac_sim-2022.2.0/exts/omni.isaac.core/omni/isaac/core/utils/”, line 36, in get_mesh_vertices_relative_to
vertices_tf_row_major = np.pad(vertices, ((0, 0), (0, 1)), constant_values=1.0)
File “<array_function internals>”, line 6, in pad
File “/data/omniverse/library/isaac_sim-2022.2.0/kit/extscore/omni.kit.pip_archive/pip_prebundle/numpy/lib/”, line 743, in pad
pad_width = _as_pairs(pad_width, array.ndim, as_index=True)
File “/data/omniverse/library/isaac_sim-2022.2.0/kit/extscore/omni.kit.pip_archive/pip_prebundle/numpy/lib/”, line 518, in _as_pairs
return np.broadcast_to(x, (ndim, 2)).tolist()
File “<array_function internals>”, line 6, in broadcast_to
File “/data/omniverse/library/isaac_sim-2022.2.0/kit/extscore/omni.kit.pip_archive/pip_prebundle/numpy/lib/”, line 411, in broadcast_to
return _broadcast_to(array, shape, subok=subok, readonly=True)
File “/data/omniverse/library/isaac_sim-2022.2.0/kit/extscore/omni.kit.pip_archive/pip_prebundle/numpy/lib/”, line 350, in _broadcast_to
op_flags=[‘readonly’], itershape=shape, order=‘C’)
ValueError: operands could not be broadcast together with remapped shapes [original->remapped]: (2,2) and requested shape (0,2)
2023-02-01 22:38:02 [22,460ms] [Warning] [] 1 contexts were leaked
/data/omniverse/library/isaac_sim-2022.2.0/ line 41: 15662 Segmentation fault (core dumped) $python_exe “$@” $args
There was an error running python

I found that this is because the following lines in return a 0 length array:
vertices_vec3f = UsdGeom.Mesh(mesh_prim).GetPointsAttr().Get()
vertices = np.array(vertices_vec3f)

This only occurs when running with the ycb_video writer. If I switch to the DOPE writer, it does not occur. Similarly, if I comment out the call to “writer_helper.save_mesh_vertices()” in, the error does not occur, and images are generated.

Fixed this by moving the object mesh to be a direct child of the root prim, rather than the default where it’s nested through an additional Xform.

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