Hey Galeon, thanks!
We have 6 main areas in the game, and in each of those we have between 10-12 level streaming volumes which we’re loading in and put on touch. In terms of optimisation, we’re still playing around with what works best, but stationary lights definitely take up quite a bit of performance (especially on console for some reason) so use static where possible - which sounds pretty obvious but even in a section where you have 2-3 close by it can cause dramatic slow down.
Visibility wise, all the usual tricks work pretty well out of the box - cull distance & precomputed visibility seem to do the trick (but add on build times so only add precomputed volume when you’re doing test builds). We used LODs quite heavily in the UDK release but at this moment in time, there seems to be a bug in the UE4 LOD system so we need to get that sorted out before we do LODing in the UE4 version. Textures we haven’t changed at all. Since we want to give PC gamers the option of full resolution settings, we just put it in the options menu to turn down the texture detail if they wish.
Hope that answers your questions?