Error when using mesh colliders

[josemendez]

That fixed the problem but when I use mesh colliders the simulation is not as good as using primitive colliders. I'm getting some extreme tunnelling. Any solution to this?

MeshColliders are quite costly. They're also hollow: only their surface is considered for collision detection. So if an object (in Obi's case, particles) gets completely inside of them, it won't be projected out. This applies both to Unity physics as well as Obi. Increasing ObiCollider's thickness and/or using a shorter timestep you could improve this a bit, but unfortunately it's just how MeshColliders work.

Obi provides a better alternative to MeshColliders: distance fields. They're much faster and considerably more robust to tunneling, both convex and concave shapes are supported. You can read more about them here:
http://obi.virtualmethodstudio.com/tutor...ields.html