Support USDZ on web (not only iOS)

[netgfx]

There is a loader for threejs now mrdoob/three.js#14219 that can support USDZ rendering on the web as well (on Chrome Windows or other platforms/browsers). Perhaps this would be something to consider because USDZ files are generally more compressed than GLB files and often have much smaller sizes which helps the initial load & render.

[elalish]

Can you give us some examples of the size difference? That is not our impression; generally speaking their internal data formats are basically equivalent. In fact glTF can get quite a bit more compressed considering it's support for mesh quantization (DRACO) and KTX2 compressed textures that USDZ doesn't have.

The main reason we don't support USDZ is because they don't have a clear physical spec of their materials like glTF does, which makes it very hard to get consistent rendering between different code bases.