How to Fix a Unity Mesh Collider Not Colliding

A mesh collider that does not collide usually breaks the convex rules. Here is how to fix it.

How to fix it

1. Mark moving mesh colliders convex

A non-convex Mesh Collider only works as static geometry. To collide on a moving rigidbody, or with another mesh collider, it must be convex. Enable the convex flag for dynamic mesh colliders.

2. Use primitives for dynamic objects

Convex mesh colliders are approximations and limited in vertex count. For moving objects, primitive colliders (box, sphere, capsule) or a compound of them collide reliably and cheaply. Prefer them for dynamics.

3. Keep non-convex for static only

Reserve detailed non-convex mesh colliders for static level geometry, which can collide with dynamic primitives. Mixing two non-convex mesh colliders never collides.

Catching the ones you can't reproduce

The hardest version of this to fix is the one you can't reproduce — it only happens on a player's hardware, OS, driver, or save state, under conditions that simply aren't present on your machine. A report that says “it crashed” or “it froze” gives you nothing to act on, so the bug survives release after release while quietly costing you players.

Automatic error capture closes that gap. Each failure arrives with its full stack trace, the device and OS, the build number, and a breadcrumb trail of what the player did right before it broke, so even a failure you have never seen becomes a specific, reproducible issue. Fold identical failures into one signature ranked by how many players each hits, and your worklist sorts itself worst-first instead of arriving as a stream of vague complaints.

This is where a tool like Bugnet earns its place. Its SDK captures every Unity error automatically with the full stack trace plus device, OS, memory, build, and game-state context, folds duplicates into one grouped issue with an occurrence count, and ties each to the build it first appeared on — so you fix the problem that hurts the most players first and confirm it is gone when its signature disappears from the next release.