When added a USDZ file to the three.js editor it loads into the scene and I can see the gizmo to control it but I can not see it and there is no materials tab connected to it.
Do you mind sharing the problematic USDZ asset in this topic?
Of course!
Though I have tried many I will share one from sketchfab.
Thank you!
Air_Jordan_1_usdz.usdz (7.0 MB)
That file appears to have USDC scene while three.js only supports USDA.
You can at least view it with the online USDZ Viewer.
There is also another online USD Viewer that can show it as well but also provides a useful workaround. You could drop your USDZ (USDC) model and then export it as a GLB file which can then be used in three.js editor to export it as USDZ (USDA) file.