OBJ does not render with texture without explicit usemtl

[YuxuanSnow]

Dear PyTorch3d developers,

i want to render an object which I downloaded from http://ycb-benchmarks.s3-website-us-east-1.amazonaws.com/. The .obj, .mtl, and .png texture image are available. However, when I tried to load the object using load_obj, the aux object only contains normals and verts_uvs, no information about texture in material_colors, texture_iamges, and texture_atlas.

I uploaded the textured object file into google drive: https://drive.google.com/file/d/1FU04gYsXy7_agL_1G9ZcjI8AQd1iY3Lx/view?usp=sharing. I wonder if you can try to load the aux and tell me how should I modify the .mtl file?

Thanks!

[bottler]

The obj file has no usemtl line.

[patricklabatut]

Such usemtl line may however not be mandatory as long as a material library has been specified: a default material can be automatically picked from the .mtl file (e.g. the first / last one). In particular, this seems to be the behavior of the built-in viewer on macOS (the shared object renders with texture without any change).

[patricklabatut]

@YuxuanSnow Could try adding the following line to the .obj file, right below the mtllib one:

usemtl texture_textured.png

[YuxuanSnow]

@bottler @patricklabatut That works after i added the line in .obj file. Thank you so much for your answer and help!

[patricklabatut]

@bottler It could still be a good idea to implement the fallback / default material.