What causes a spinning object applying torque around the wrong axis?

The torque is applied in the wrong space or about an axis that is not a principal axis of the body, so the inertia tensor couples the rotation into a tumble.

How do I catch this when it only happens for some players?

Capture it automatically from the player's device with the full stack trace, the device and OS, the build, and a breadcrumb trail of what they did. That turns a vague complaint into a specific, reproducible issue you can fix without owning the hardware it happens on.

How to Fix a Spinning Object Applying Torque Around the Wrong Axis

Quick answer: Apply torque about the body's intended local axis transformed to world space, or align the object so its spin axis is a principal axis, so it spins cleanly.

A flywheel or top that wobbles and tumbles instead of spinning about one axis is fighting its own inertia tensor, often because the torque is in the wrong coordinate space. Here is how to fix it.

How to fix it

1. Apply torque in the right space

AddTorque(Vector3.up * t) spins about the world up axis; to spin about the object's own axis use AddTorque(transform.up * t). Mixing them causes precession-like tumbling.

2. Spin about a principal axis

Bodies rotate stably about their principal inertia axes. Model the object symmetrically about its intended spin axis, or set inertiaTensorRotation so that axis is principal.

3. Freeze unwanted rotation

If only one spin axis is desired, lock the other rotation axes via rb.constraints so torque cannot bleed into a tumble.

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 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.

Most of the time the fix is small. Seeing the failure clearly is the part that actually costs you.