Sphere rolling over seams between mesh colliders jumps

I have a rather simple setup for my game. The player is a ball with a sphere collider and the level is made of meshes with mesh colliders. When the ball is rolling fast enough and encounters a seam between two mesh colliders, it sometimes hops. It doesn’t always hop, and usually only hops when rolling fast. This can be replicated using Unity planes (which have mesh colliders attached) so I’m pretty sure the meshes aren’t a problem. I’ve tried exactly positioning the test planes as well as vertex snapping and I’m sure they’re aligned correctly.

In my searching, someone said this doesn’t happen with box colliders. However, in my testing it does. The ball is still hopping over seams in box colliders. It’s not quite so bad though, so I had considered redoing all the level with box colliders, but this is not practical considering there are many slopes and irregular shapes involved. Also the time involved with placing box colliders over the entire level is not acceptable. And of course the hopping is still there, so there’s no real point in it anyway.

Right now I’ve technically fixed it, but in a way that is probably unacceptable: I’ve set my physics timestep to 0.001. That’s 1000 physics frames per second. It works, but that seems very, very overkill. I don’t want to keep it this way permanently.

I’ve also seen this question asked a number of times and there’s no answer given. I don’t know if there is no answer to this problem, or it’s just no one has said it on answers or the forums. This seems like such a small problem to be holding me up, and honestly I don’t see any way around it.

I had this SAME problem in the past (yep - with a rolling sphere). What I did was change my design approach completely. May I suggest designing your levels in a way that won’t have annoying seams like that?


I would like to somehow highlight this problem for Unity developers.

I am working on the game with a ball where pieces are modular and user can build entire levels in level editor. There are rails, ramps up and down etc. However this one physics problem is totally destroying the game!

I struggle finding proper solution for this in year 2020.

Anyone who finds any decent solution to this problem please contact me on raptolion@gmail.com
Thanks a lot

I am having this exact same issue but with just an entire mesh collider, some parts have “seams” that were fixed in the 3d modeler but when In game, the mesh collider still causes the ball to hit this invisible bump and I am on version 2019.3.15f1