GI Improvements

We have improved the global illumination in the exhibition room.

The issues we want to improve are the different brightness of the same wall object, unnatural light leakage, etc. When we investigated this issue, we found an error about UV overlap when creating a light map.

When investigating the cause of this error, two modeling issues were found.

First issue is that when export a collection using Blender’s Bundle Exporter tool, it will be treated as a single object in Unity, and the UVs of each meshes in the collection will overlap.

Another issue is that when editing in Blender, some meshes had multiple UV maps defined.

Therefore, to avoid duplication, we re-edited it in Blender, exported it on a mesh-by-mesh basis rather than a collection-by-collection basis, and then assembled it in Unity.

As a result, the different brightness was eliminated, but light leakage and unnatural shadows still remained. Looking back, the UV overlap error was not eliminated.

So we looked into it again and found a lot of information online about UV overlapping. Basically, if try to fit the same UV shapes together when creating a UV map, the pixels will overlap with the adjacent UV shapes depending on the light map resolution.

For this reason, we added gaps to the UV map shapes and was finally able to improve the situation.

There are still some GI issues with the exterior walls and ceilings of the museum, so we will be improving them one by one.