Seems `load_obj` can not load `vertices` with `vertex-color`

[Matt-V50]

I have an obj file that includes vertex-color.

It looks like

vn 0.228076 -5.246246 2.607272
v -0.053804 0.709615 -0.144573 0.235294 0.992157 0.125490
vn -0.542669 -4.832255 3.054440
v -0.056966 0.711699 -0.141544 0.235294 0.992157 0.125490
...

How did this file come from

• Download the ply file
  • And I found it from the official tutorial Mesh plugin
• Open it in MeshLab
• Export it to the obj file

I checked the key method _parse_obj, as you can see below

https://github.com/facebookresearch/pytorch3d/blob/7978ffd1e4819d24803b01a1147a2c33ad97c142/pytorch3d/io/obj_io.py#L459-L464

And it seems can not load vertex-color, cause the code use token[1:4] only

[bottler]

You are right that we do not support vertex color in obj files. Let us know if you would like to contribute such support.

Just to respond to the title: the vertices are loaded but their colors are not.

[wwdok]

I opened a related issue about supporting loading obj with vertex color. But in my case, the vertex color range is [0,255], here is [0,1]. If someone contribute this feature, please consider these two cases ~ (I am new to pytorch3d, i think it is hard for me to contribute this feature correctly now)

[Matt-V50]

Use trimesh as a temporary alternative.

import trimesh
trimesh.load(obj_file)
colors = torch.Tensor(tri_mesh.visual.vertex_colors)  # [N, C], Channel = 4 for default.

Btw, pytorch3d can not load files by specific encoding.