Well, the title says it all, to be honest!
Look at this image:
Now, the ceiling is fine, but the curtains are way too bright! Thing is, they are both the same material!
Any help?
I managed to fix it in the end, I changed the mobility to static and that fixed it all!
Yes, you have some nice soft shadows on the ceiling there. A couple of questions about the curtains. Is this happening after you built lighting with them included? If you’ve moved or modified those meshes in any way your static lighting is going to need to be rebuilt.
If that isn’t the case, then maybe your lightmap resolution on the curtains is too low.
Another thing to try is to use the Lighting Only view mode in the Editor. From here, you can see which lights are acting on your curtains and how. There may be a light (directional light?) acting on them from the other side which could indicate an issue with the Normals on your mesh.
Decrease the Volumetric Lightmap Detail Cell size might solve your issue.
