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 Construct 3 Physics Jitter After Scaling a Sprite at Runtime

Q: What causes Construct 3 physics jitter after scaling a sprite at runtime?

The Physics behavior creates its collision fixture from the object's initial size, and resizing the sprite at runtime leaves a stale fixture that no longer matches the visual, causing jitter and bad collisions.

Quick answer: Rebuild the physics body after a size change with Set collision polygon / re-enable the behavior, or scale by replacing the object rather than resizing the same instance.

When you grow or shrink a physics sprite during play it starts vibrating and tunneling. The fixture still uses the old size. Forcing the body to rebuild after the scale change re-syncs collision with the visual.

How to fix it

1. Rebuild the fixture after scaling

After changing the object's size, trigger a physics body rebuild (toggle the behavior off and on, or use the action that recreates the fixture) so the collision shape matches the new scale.

2. Set the collision polygon

If the shape comes from the collision polygon, update it to the new dimensions after scaling so the fixture is regenerated at the correct size.

3. Scale at spawn, not at runtime

Where possible set the final size before enabling physics (or spawn a correctly sized instance), avoiding a runtime fixture mismatch altogether.

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 Construct 3 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.

Reproduce it once with full context and the fix writes itself. The hunt is the expensive part.