What causes light leaking at wall-floor corners in a baked scene?

When a lightmap chart has too little padding or wall and floor meshes do not overlap at the corner, baked light from outside bleeds across the seam into the interior corner.

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 Light Leaking at Wall-Floor Corners in a Baked Scene

Quick answer: Increase lightmap UV padding, overlap wall and floor geometry slightly at corners, and raise lightmap resolution so charts do not bleed into each other.

Corner light leaks are charts bleeding at a thin seam. More UV padding, slightly overlapping geometry, and higher resolution stop outside light crossing the wall-floor join.

How to fix it

1. Increase lightmap padding

Raise the lightmap UV padding / pack margin so neighboring charts do not sample each other's texels, which is what carries the leak across the seam.

2. Overlap geometry at corners

Extend the wall slightly past the floor (or vice versa) so there is no infinitely thin gap at the corner for outside light to pass through during the bake.

3. Raise lightmap resolution

Higher lightmap density gives the corner more texels, so a single bright bleeding texel no longer paints a visible streak of leaked light into the room.

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.

Ship the fix, watch the signature disappear from the next build. That's how you know it's really gone.