concave dynamic meshes collision

I have a dynamic player created mesh that can be concave and need to collide with another dynamic player created mesh that can be concave too.
I have a mesh collider for both the whole shapesmeshes but they aren’t colliding since unity do not detect collision for concave mesh colliders, only convex ones.
I can’t have convex mesh colliders since my meshes do need to go one inside the other in some cases.
I already tried with multiple child colliders since my dynamic meshes are made of voxels but these primitive colliders become too many for unity to handle (there can be thousand of them).
I thought of grouping some voxels togheter to create less mesh colliders and try to keep them convex but this solution is also too slow.

Anyone knows of a better and performance wise solution?

You’re on the right track, but you need to group the colliders into a few convex objects.

There have been multiple papers and articles written on techniques to split concave objects into the minimal set of convex ones. Id suggest you google and start reading.

Edit: It occurs to me that you a r calling these “voxels” (a bit of a misnomer but just something that many people are confused with these days.) If that means that they are totally filling or not-filling squares in a grid, you could use an octree approach to subdividing them into 3Dsquare areas.

With a bit of cleverness, if that was still too many, you could then recombine ones that share common faces along an axis.