Hey so I am running into this issue where i have modular roof and floor tiles, but light seems to affect each differently and I am not sure why. They have been designed to grid snap accurately in maya, and show no visible seams when the scene is “unlit”. However, light continues to bleed through and make the tiles look different, even with two-sided textures turned on.
This is a known issue in UE4. Basically the meshes are being lit using different threads, meaning each thread doesn’t know the lighting for other threads, which causes inconsistent shadows. This is remedied usually by avoiding being overly modular. You have a lot of meshes to make the ceiling. This causes performance issues (more draw calls) but it can be solved by simply making the ceiling one large mesh.
