Thanks for the reply! the main reason i am looking for hide and off load meshes is for performance reason! I tried level streaming, in Editor it works pretty well! the level load and unload time was almost seem less, there was a small lag but it was ok! but for some reason when i compile the project, and run it from exe file. the lag of level streaming was very high, i had to wait for the objects to load and off load. same machine same setting, in Editor it was fine. thn I tried to use cull distance volume to counter the performance, but i got another strange issue! non of my imported mesh is able to cull by volume. if I add objects like box or sphere from editor, in the same scene thy work well with Volume. but non of my imported mesh works!! dont know how to make it work!