Apple has introduced a beta (https://developer.apple.com/news/?id=01132020a) of a new Reality Converter app that “makes it easy to convert, view, and customize USDZ 3D objects on Mac.”
With it you, can drag ’n drop common 3D file formats, such as .obj, .gltf and .usd, to view the converted USDZ result, customize material properties with your own textures, and edit file metadata. Apple says you can even preview your USDZ object under a variety of lighting and environment conditions with built-in IBL options.”