What causes Construct 3 collisions not detecting?

The object's collision polygon is wrong or disabled, the on-collision condition is on the wrong objects, or fast movement skips the overlap, so collisions are missed.

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 Collisions Not Detecting

Quick answer: Set a correct collision polygon, use On collision or Is overlapping with the right objects, and handle fast movement so the overlap is not skipped between ticks.

Construct 3 collisions that do not fire are usually a polygon or condition problem. Here is how to fix detection.

How to fix it

1. Fix the collision polygon

Each object has a collision polygon; if it is mis-shaped, tiny, or collisions are disabled, overlaps are not detected. Edit the polygon to cover the sprite and ensure collisions are enabled.

2. Use the right condition and objects

On collision triggers once when two objects meet; Is overlapping checks continuously. Use the one you need, between the correct object types or instances, or the event never qualifies.

3. Handle fast movement

A fast bullet can pass through a thin object between ticks. Enable bullet behavior's collision checks, move in smaller steps, or widen the target so the overlap is caught.

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.

The errors you never hear about are the ones quietly costing you players. Visibility turns them into a worklist.