I’ve been trying to use HISM, but I’ve noticed that the performance is strange. Adding a large amount of instances is fine. Once they are loaded, the performance is great. There is lag on the game thread when adding initially, but I understand that adding a large amount of collision enabled things would lag the game thread.
What I do not understand, is once I have added about 20,000 HISM planes to the scene, removing or adding just a single instance lags the game thread significantly. But how can this make sense?
Doesn’t UE use HISM for foliage? With the foliage tool I can have a million instances in the scene, and removing a couple or adding a few more doesn’t cause noticeable lag.
So why is there a massive performance cost when adding just one or two instances, or removing a couple instances, to a HISM component, once that component has 20k+ instances? And why does this same lag not occur with foliage, where the instance counts can be much much higher?
What is going on here?
Unreal 5.1
Thanks