UE4 to UE5 migration is not going smoothly. Particularly, UE5 likes to break physics. So now I have to deal with jittery objects that sometimes shoot themselves across the room.

... The reasonable explanation is that the env is haunted. 👀👻

Drawers in the room also like to fall down as soon as your press play. The robot in this env will be clearly scared shitless. Lol.

I don't think the game Space Engineers ever solved the "clang" problem. Basically they have physics in their game and certain objects (pistons mostly) would cause glitches and just decimate whole ships. Usually more prevalent in multiplayer. They nicknamed this phenomenon "clang". It was the most complained about bug. As far as I know it was never completely solved.

@Demolishun Space Engineers has got orders of magnitude less janky than the early days.

Still not perfect though.

@kwilliams is there still a speed limit of… what was it… 100 m/s because the physics breaks at higher speed?
This was my biggest issue with that game.

@Lensflare yes but it's as much for performance as stability. There are mods which raise the limit by orders of magnitude without the simulation breaking.

Update: what I have found so far as a plausible explanation is the collision meshes being "too close" before the start. So they basically collide before you start the simulation. So they go nuts.

@Archive Did you switch to the Chaos Physics Engine introduced in UE5 or did you keep PhysX?
As far as I remember Chaos is in a separate thread with fixed Ticks in comparison to PhysX running in the same thread. So a rather big change which can have those side effects..

@Crowns yuuuuuup. And I am not sure if just changing the collision mesh actually solves. We used to use simple meshes, and changing them to complex meshes seems to solve the problem but I'm not sure if it would cause any adverse effects down the line.

The fact that the sim is very sensitive to initial conditions bothers me. It is what it is I suppose.

@Archive Why are drawers implemented with collision? I'd much prefer a joint.

@lbfalvy because there's a darn robot in this env and it needs to be taught right from wrong.

@Crowns update: it didn't solve.

@Archive idk how the robot moves, but is there a functional difference from its perspective between a drawer that slides in a holr and one that moves on rails?

@lbfalvy 🤔 I think you're overthinking it. I don't think we're using collision in that sense.

@Archive well I don't know your project so anything I say is overthinking based on the information I have.

Bug, feature, it is a matter of perspective. Just rename your game to "<game name>: Poltergeist" and move on with your life.