Hi @MaZihao - Cesium for Omniverse streams data to a lower-level system called Fabric which bypasses the USD stage, so I’m not sure if what you’re trying to do is possible; however it might be possible in the future once Fabric supports physics.
One alternative is to use Cesium Clips to download a glTF of the portion of the buildings dataset you need and import that into Composer. Just be aware that some datasets like Google 3D Tiles are not available for clipping.