If My BP has a mesh with a per-poly collision, I can set simulate physics to false to freeze it in place, but so far when I set it back to true the physics does not start again. Is there a way to fix this?

per-poly collision

This would mean complex collision, meaning you can’t simulate physics in the first place. Unless you tricked UE with UCX and are using Simple with a lot of polys. In which case this seems to work fine:

Image from Gyazo


So the real question is what else are you doing we do not know about. Do tell. Perhaps you mean that the momentum is not preserved once the physics kicks back in? That’s expected, ofc.

I tested that set simulate physics successfully was set back to true, but the physics still did not restart.