Questions on embedded GLTF PBR Texture

Just now, I exported GLTF material from Blender, and during conversion, I am getting this error:

Traceback (most recent call last):
  File "gltf2usd.py", line 1126, in <module>
    convert_to_usd(args.gltf_file, args.usd_file, args.fps, args.scale, args.verbose)
  File "gltf2usd.py", line 1114, in convert_to_usd
    GLTF2USD(gltf_file=gltf_file, usd_file=usd_file, fps=fps, scale=scale, verbose=verbose)
  File "gltf2usd.py", line 70, in __init__
    self.convert()
  File "gltf2usd.py", line 1099, in convert
    self._convert_materials_to_preview_surface()
  File "gltf2usd.py", line 482, in _convert_materials_to_preview_surface
    primvar_st1_output=primvar_st1_output
  File "gltf2usd.py", line 1074, in _convert_texture_to_usd
    texture_name = self.unpack_textures_to_grayscale_images(image_name, color_components)
  File "gltf2usd.py", line 1035, in unpack_textures_to_grayscale_images
    raise Exception('Unsupported image type!: {}'.format(img.mode))
Exception: Unsupported image type!: RGBA

So far, I have tested 3D GLTF from Sketchfab only and never had issue. Only today I am setting up the shader based on GLTF Blend example. Then I exported the object and getting an error. It does not seem to like RGBA, maybe I should change it to JPG?

[kcoley]

@enzyme69 yes what @ox says is correct since the logic initially assumes that you are using an ORM texture (occlusion: r, roughness: g, metallic: b). The texture logic definitely needs refactoring. I will look into that later today to make it more robust. But in the meantime, @ox solution should work.

[ox]

So the texture it’s failing on is the Ambient Occlusion png, which has 4 channels. The _convert_materials_to_preview_surface function goes in expecting to use the r component of the occulusionTexture image as the occlusion map, sees a 4 channel image, which jumps to logic trying to unpack a glossiness map.

I think if you change your ao.png to only be 3 channels, it should work