I just finished creating a obj importer so that I can convert meshes into RMC data. In a test I decided to try and compare RMC performance with Hierarchical Instanced Static Mesh. HISM is a lot faster and if you have collision enabled (I was using per poly collision in both RMC test and HISM test) it’s not even comparable. I ran a test with 317 tree stumps, for a total of around 1.5 million polygons. I had the converted obj stump duplicated and rotated into place (identical transforms as with the HISM) I loaded up a RMC and turned collision to true. This was barely playable, serious FPS drops. I did the same test instead spawning instances of the same stump on the HISM component, but this time I imported the mesh through the editor. I set complex collision on the static mesh. UE4 barely slowed down. The test was barely playable using RMC, and with HISM I was able to put the oculus rift on and walk around jumping around on the tree stumps. This got me thinking about collision differences. So I ran the same test again, but this time I spawned both, all 317 stumps on an single RMC and also all 317 stumps on HISM, but I turned collision off on the RMC, and I turned visibility off on the HISC (for some reason this still allows the collision to exist). This basically made the RMC run as fast as the HISM. Very bizarre but also really cool. I guess the downside would be having to double spawn up front, but performance wise it’s so much better.