(This is a copy of my earlier post on reddit.)
I was toying around with 3D physics, and I have two questions regarding trimeshes.
First, I noticed that bodies whose collision is handled by trimesh shapes can’t detect each other, and after a bit of research I found out that this is not considered much of an issue. I’m thus wondering if there’s any workaround to it, except adding a second layer of convex (primitive maybe) shapes (which would kinda defeat the point of having the auto trimesh shape, I guess) and if there’s any specific reason to this behavior (performance?).
Secondly, rigidbodies using a trimesh seem to have an inconsistent behavior, often (but not always, which is even more puzzling) not responding properly to gravity. Let’s say I make a simple pole, angle it 45°, and drop it on a staticbody floor; if the pole shape is convex, the pole behaves as expected, landing its lower end first, and rotating until it’s flat on the ground. If it has a trimesh shape, It correctly falls until its lower end lands, and then most of the time it remains eerily angled at 45° (seemingly stopping all calculations), while sometimes it behaves like the convex.
I’ll be very thankful for any insight I can get on this.
EDIT: I think the second part has to do with a misplaced origin point in the model.