Exporting textures with fewer than 4 channels is not supported. In case when need to cut out empty channels for example.
Please add a RenderPasses-like option - similar to the one in EmberGen.
Hey thanks for reaching out about this. I’ll reach out to the team about this, but for now you can use the RGBA Split and RGBA Merge nodes to isolate channels from inside IlluGen. This will still result in an RGB image, but is something that might help in the meantime!