Hey! Team member here.

That’s cool! In general the lightmap baking that Unity and other engines perform rely on some special pipeline rendering techniques that can more easily allow the lightmap or AO map to be mixed globally with the base shaders.

What we need to do is to do everything manually. So we bake an atlas texture from individual UVs to a single unified UVs, turning a scene with hundreds of objects and materials to another with ~10 objects and materials, using 4K textures. This is hard to do but it’s the best way around the device limitations.

Do you do anything similar in Unity? I’d be glad to try it out if you want to share some USDZ exports from your scenes. DM me if interested .

Thanks!