In my experience, you need to do quite a bit of grouping in Hammer before importing your map, otherwise the default culling can't keep up with all the separate parts. Keep in mind that every brush you import is both a new static mesh actor and a new asset, so optimisation goes out the window if you just import everything separately.
Yeah, I'm aware. Thanks. I will try different methods.
- Merge in UE with build in functionality
- Merge in UE with an own geometry scripting tool
- Try to use the old "compute visibility" route generating a grid (should be still in the engine for mobile)
- trick the occlusion algorithm in UE to be more loose
- and last resprt would be going through the huge maps by hand and make groups (it's not Hammer but NetRadiant for ET