Hello, does this static mesh use Nanite? Nanite has it’s own occlusion culling system.
In addition, (afaik) even if an instance is still there behind the wall, its verts can’t be seen. Given the density of instances in the background, I expect a terrible quad overdraw in the open field scene. Placing a big wall behind the instances, you are avoiding the overdraw problem and not actually reducing the poly/instance count.
Hi, yes that was using Nanite, and yes the occlusion is being done by Nanite - but that’s the point I think (this was 2 years ago :D)
Nanite gives us the single sets of drawcalls and culls the data - it’s not perfect though and ISMs still seem to be faster for rendering (I need to do some more tests in 5.5, last tests were in 5.3). I’m not 100% sure on this, I need to do some more research but my tests seem to back it up - with modular instances they seem to be sliced better.
Another benefit for modular instances is their re-usability within scenes, adding variety for free, reducing overall VRAM and disk footprint, and fast spawning and transforming. They’re a good way to get rid of the dreaded stutter.
I know it’s an old thread 
I was serching the best way to implement a modular building system (runtime, maybe multiplayer) and I found this.
Anyways, I will opt for ISMCs inside a manager actor, mainly for memory (and I can also share simple integer indexes between players to save bandwidth 
).
Probably, to solve occlusion issues, it’ll be good to divide the map into a grid and use one component per cell, like foliage and PCG do.