Well, thanks for looking into it.
Is it possible to… like… poke it with a stick, or something? I waded through a dozen or so forum posts, reddit threads, and other answerhub questions, all about this issue before I got here. It’s pretty fundamental functionality which is supported by PhysX, but just not exposed by UE4. (Or was partially exposed in 4.20 but the work was never finished.)
From what I’ve gathered, it’s fairly easy to do if you’re willing to edit engine code, but a huge pain in the butt if you’re not. I’m going to keep digging, but PhysX gives me headaches (not naming variables doesn’t make code run faster, Nvidia!) and UE4’s interface with it is… labyrinthine.