How to Fix a Conveyor Belt Not Moving Objects Resting on It

A conveyor where the texture scrolls but the crates just sit there is only animating the visuals. The physics surface is static. You have to actively push the resting bodies along. Here is how to fix it.

How to fix it

1. Push contacting bodies

In OnCollisionStay, drive each contacting rigidbody toward the belt's surface velocity, e.g. set the along-belt component of its velocity to the belt speed while leaving the other axes intact.

2. Use MovePosition for kinematic belts

If the belt collider itself is a moving kinematic body, move it with Rigidbody.MovePosition so contact friction naturally drags objects, then wrap its position to loop the belt.

3. Keep friction sane

Give the belt a PhysicMaterial with enough friction that objects do not slide back, but not so much that they jitter; combine with the applied surface velocity for reliable transport.

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.