Error:Non-convex MeshCollider with non-kinematic Rigidbody is no longer supported since Unity 5? So?

Trying to pick up Unity for the next project, I created 2 gears to simulate the gear interlock motion with backlash.



but the test has a problem. non-conex collider can't display as the green mesh, the gears don't collide, as the gears pass through each other.




convex collider can run without error, but it can't satisfy my need.

BTW, some other thought:
1. I find the Unity physics APIs are very different to the PhysX APIs although its backed by PhysX, missing many features, I am a bit disappointed after 10 years or I missed something?
2. A poor doc about physics and very outdated tutorial https://learn.unity.com/tutorial/3d-physics# created in 2013.

For many Unity developers who stick with this engine, maybe it's not a problem, but my experience can't give it a decent score after spending 2 days to google for doc, tutorial, and sample, but still can't get it working with such "matured" engine. In my previous project, I built the gears simulation demo for a robot application with ODE + OpenGL in 2 days from scratch in 2005.

Env:
Unity: v2019.1.12f1
MacOS 10.14.6

 

One solution might be to use an asset like this: https://assetstore.unity.com/packages/tools/physics/concave-collider-4596. It seems to generate nice collider arround an object, however it's not that cheap

 

if you need a concave dynamic object you should make a "compound" collider.

for the gear example you can have a cylinder collider (don't think there's a primitive cylinder collider, maybe the capsule can be of use, but you can make a convex-mesh collider with this shape) and a separate triangle/wedge collider for each one of it's teeth (again, no build in primitive with this shape, make a convex-mesh collider).

just parent it all up so that each gear the center is the parent and each tooth is a child of it and it should work.

 

Thanks, but it seems very unstable and outdated.

Right, it's a solution. Cheers.

 

Lemme know how that turns out for you.

 

Nice..I removed the Mesh collider and inserted the box collider