The Global Illumination by Light Propagation Volumes is progressing in a nice way. Even though this is an artifact in a weird way, it still produces a nice result. The surface is too thin for the grid to not capture both sides. Posted Image But it looks nice.
But not all is good, there’s still weird artifacts:
Sometimes the shadow testing fails when injecting lighting into the grid, I guess this is to do with the resolution but I’m still not sure, I think there’s more to it. Example: The shadow testing should have succeeded, but no indirect illumination is present.