I could compress the OBJ models with draco compression technique. Referred this link for draco compression : https://github.com/google/draco
and this compression has generated compressed files with drc extension.
How to load these drc files (compressed files) into Cesium app?
I was going to suggest using Cesium ion, which should be able to Draco compress your point cloud, and then CesiumJS automatically knows how to decompress that. But it looks like that option currently isn’t exposed so I opened a feature request for it: