What causes VoxelGI light leaking and blocky bounce in Godot?

VoxelGI voxelizes the scene at a fixed resolution, so coarse voxels straddle thin walls (leaking light) and quantize bounce lighting into visible blocks.

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 VoxelGI Light Leaking and Blocky Bounce in Godot

Quick answer: Raise the VoxelGI subdivisions, tighten the extents to cover only the relevant area, thicken thin walls, and bake so voxels resolve walls and bounce smoothly.

VoxelGI works by turning the scene into a voxel grid. Coarse voxels leak through thin walls and make bounce light blocky. Increasing subdivisions and fitting the extents sharpens it.

How to fix it

1. Increase the subdivisions

Set the VoxelGI node to a higher Subdiv (e.g. 128 or 256) so voxels are small enough to resolve thin walls instead of bridging them and leaking light.

2. Tighten the extents

Shrink the VoxelGI extents to wrap only the gameplay volume; a smaller extent at the same subdivision yields finer voxels exactly where you need them.

3. Thicken thin walls

Walls thinner than a voxel always leak; give them thickness greater than one voxel so the voxelization actually blocks the bounce.

4. Bake and tune energy

Press Bake on the VoxelGI, then adjust its Energy and Propagation; rebake after geometry changes since the voxel data is static until re-baked.

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.

Reproduce it once with full context and the fix writes itself. The hunt is the expensive part.