GLTF material import bug? (swapped channels)

[Armikron]

Hello. Just playing around with the engine and noticed something strange.

Importing GLTF file exported from Blender 3.1.2, metallness and rougness maps were combined into single shading map.

It looks like metallness map was made into Blue channel, but it supposed to be in Red one?

It's solvable using material graph, but basemat requires metallic to be in Red.

Unigine 2.15.1 Community Edition, Windows

Edited April 14, 2022 by Armikron

[silent]

Armikron

GLTF import support currently is in very early stage, but textures channels should not be swapped on import.

Could you please send us this GLTF file example so we can check on our side?

Thanks!

[Armikron]

Hello.

Turns out Blender is the one combining metallic and roughness maps into one RGB8 PNG and putting metallic map into Blue channel.

Blender cites GLTF standard for doing so: https://docs.blender.org/manual/en/latest/addons/import_export/scene_gltf2.html

The question then is: should not Unigine swap metallic channel to Red on import since its basemat expects it to be that way? Or at least give an option on import.

Hope GLTF support is getting attention, Blender's FBX support is not great.

Image shows material graph in Blender of GLTF that's imported back. Exported GLTF attached.

gltf_export.zip

[werner.poetzelberger]

hi.

I think, that the channels need to be swapped during import.

GLTF differs from Unigine shader handling as explained.

Even better would be to adopt the standard of GLTF and the shading channel assignments.

GLTF has a lot of potential but of course it is also more limited than other formats.

So as the base standard, it is absolutely beautiful. Would totally make sense to adopt this standard in some way, and support it.

 

Edited April 15, 2022 by werner.poetzelberger