Is there support for using multiple UV channels in AR QuickLook in iOS17?
One important use case would be to put a tiling texture in an overlapping tiling UV set while mapping Ambient Occlusion to a separate unwrapped non-overlapping UV set. This is very important to author 3D content combining high-resolution surface detail and high-quality Ambient Occlusion data while keeping file size to a minimum.
In short? No.
Follow up: Apparently, since iOS16, there is actually support for this in AR QuickLook / USDZ. The VisionPro USDZ asset on Apple.com, is using AO maps in UV2: https://www.apple.com/105/media/us/apple-vision-pro/2023/7e268c13-eb22-493d-a860-f0637bacb569/ar/apple_vision_pro_ios16.usdz
The problem is that there seems to be basically zero documentation on how to author these USDZ files, so I started a thread on the OpenUSD forum to investigate: https://forum.aousd.org/t/linking-ao-texture-map-to-secondary-uv-channel-st1/446/3
Apparently, exporting USDZ with these charateristics is possible via the Maya USDZ exporter, but as far as I can see there´s no support in Blender (my preferred authoring platform). So we´re now looking to move our pipeline to Maya and test compatibility.
I really hope that Apple will up their game and expose these options in an updated (and much improved) version of Reality Converter soon.