I'm looking for a method to check who sits on a certain chair. Preferably something only triggering when someone starts to sit down on it. I've tried adding a script to the chair and use an OnActivate block, but this only works for the player (same for the OnActivate Event Handler). Any suggestions how to make it work for npcs? Thanks.

Not very elegant, but one way might be to use a very small trigger zone which detects who is triggering it. Perhaps one of the others will think of a better method.

I added a trigger zone to the mesh and it does indeed work. Thanks.