We were adjusting the lighting throughout the Hept building, and when we baked the lights for global illumination, the ceiling on the first floor was emitting strange light.
We haven’t installed the lighting yet, so it would be strange if it didn’t look like the one below.
We investigated various things, such as whether we imported the light from Blender by mistake, whether we specified self-emission for the material, whether there was wraparound from the background lighting, etc., but we could not pinpoint the cause. Baking for investigation will take time, so I put it on hold for now.
During our investigation, we discovered that the building structure object was at the maximum atlas size for the lightmap. Although it was not an error, we thought it affected the lighting, so we divided the object into smaller sizes.
The object that was mysteriously glowing also had to be split, but the glowing surface remained only in the split part. Therefore, when we looked at the modeling of the object in detail, we discovered a surface with a width of 0. When this was removed, the baking result was normal.