How to Fix Normal Seams at Chunk Borders in Godot Terrain Meshes

A lighting line at a chunk border means border normals differ between chunks. Calculating each border normal from neighboring chunk heights, not just the local chunk, fixes it. Here is how.

How to fix it

1. Sample neighbor heights for border normals

When building a chunk mesh, include a one-vertex apron of heights from each adjacent chunk so the border normal is computed from the same surrounding triangles the neighbor sees.

2. Average shared-edge normals

If you cannot read neighbor data at build time, after generation average the normals of vertices that share a world position across chunks and write the result back to both meshes.

3. Avoid recomputing only on the local SurfaceTool

SurfaceTool.generate_normals() only sees the current chunk's faces. Feed it the apron geometry, or set the border normals manually, so it does not produce edge-only normals.

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 Godot 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.