How to Fix a Decal Projector Bleeding Through Walls Onto Other Surfaces

A bullet hole or blood decal shows up on the wall behind the one you hit. The projector's box is too deep and projects through everything inside it. Here is how to contain it.

How to fix it

1. Reduce projection depth

Tighten the projector's depth (the box length along its forward axis) so it only reaches the surface you want to mark. A deep box paints every surface it passes through, including walls behind the target.

2. Use rendering layers

Assign the decal projector a rendering layer mask that matches only the geometry it should affect. This keeps a floor decal off the walls and props that happen to fall inside its volume.

3. Apply angle fade

Enable angle-based fade so the decal fades out on faces that are nearly perpendicular to the projection direction, preventing it from smearing across edges and wrapping onto adjacent surfaces.

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.