RuntimeError: Tensors must have same number of dimensions: got 4 and 5

[pbonazzi]

I have run into the following error when running scripts/create_mvr_data_from_mesh.py for the first time

`  File "scripts/create_mvr_data_from_mesh.py", line 207, in <module>
    images = renderer.shader(fragments, meshes_batch, lights=lights, cameras=cams)
  File "/home/mengqi/.conda/envs/pytorch3d/lib/python3.8/site-packages/torch/nn/modules/module.py", line 722, in _call_impl
    result = self.forward(*input, **kwargs)
  File "/home/mengqi/.conda/envs/pytorch3d/lib/python3.8/site-packages/pytorch3d/renderer/mesh/shader.py", line 376, in forward
    images = hard_rgb_blend(colors, fragments, blend_params)
  File "/home/mengqi/.conda/envs/pytorch3d/lib/python3.8/site-packages/pytorch3d/renderer/blending.py", line 84, in hard_rgb_blend
    return torch.cat([pixel_colors, alpha], dim=-1)  # (N, H, W, 4)
RuntimeError: Tensors must have same number of dimensions: got 4 and 5`

As you can see the error is raised at line 206 of the script and is caused by this call:
images = renderer.shader(fragments, meshes_batch, lights=lights, cameras=cams)

Can you help me with this ?

Version
Python: 3.8
Pytorch: 1.6
Pytorch3D : 0.6.1

System
System='Linux'
release='4.15.0-188-generic'
version='#199-Ubuntu SMP Wed Jun 15 20:42:56 UTC 2022'
machine='x86_64'

Note
In the README.md file you say to run external/prefix , but I could only find external/prefix_sum.
I have successfully run all the setup.py scripts.

[lxxue]

Hi, this is probably a pytorch3d version problem. We were working with an old version, and the new version is incompatible. I update the installation part in the fix/install branch. Could you check it out and create the environment again to see if you still have an issue? Things work fine on my side with this new installation.

[pbonazzi]

Well done , I have already managed to solve it on my own , by tracing back the problem in pytorch3d library .

It had to do with the renderer.shader function , in your script I have done the following

            # add these imports
            from pytorch3d.renderer.blending import BlendParams, hard_rgb_blend
            from pytorch3d.renderer.mesh.shading import flat_shading

            # replace these lines (206)
            # images = renderer.shader(fragments, meshes_batch, lights=lights, cameras=cams)
            texels = meshes_batch.sample_textures(fragments)
            colors = flat_shading(meshes=meshes_batch, fragments=fragments, lights=lights, cameras=cams, materials=renderer.shader.materials, texels=texels)
            images = hard_rgb_blend(colors[0], fragments, BlendParams())

[pbonazzi]

It works like a charm with #21