How to Fix Lightmap Seams on Meshes

Lightmap seams are UV island padding and splits. Here is how to fix them.

How to fix it

1. Add UV island padding

Insufficient padding between lightmap UV islands lets baked lighting bleed between them at the seams. Increase the padding (in the UV layout or import setting) so islands do not contaminate each other.

2. Keep continuous surfaces together

Splitting a continuous surface across separate UV islands creates a seam where the two islands' lighting meets. Keep continuous surfaces on one island where possible so lighting is continuous across them.

3. Increase resolution or stitch seams

Higher lightmap resolution reduces seam visibility, and some engines offer lightmap seam stitching that blends across UV seams. Use these to minimize the seams that padding and layout alone cannot remove.

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.