Help with lighting issues

I did a test and created some “modular” pieces that I could put together. The meshes consist of a floor plane, wall plane, and ceiling plane. It’s working great so far but I’m having some issues with the light blending seemlessly

Any ideas?

Check the twitch stream “Lighting Techniques and Guides”. It covers most lighting issues including this seam appearance.

You shouldn’t construct things that way–as you can see it creates lighting issues, but it’s also bad for performance because it increases draw calls. Since those meshes are so simple it’s better to model a unique mesh in your 3D software than trying to construct it from multiple parts.

Specifically, the jagged edges are caused by your lightmap UVs not being parallel to the pixel grid. Ideally, every UV island edge would be straight horizontal or vertical, with no diagonal lines.

Okay I have one other question. If I create my meshes room by room and put them together in UE4, would it be best to texture each room with one large 4096 texture or do separate textures for floor, walls, ceiling, etc? I know more textures means more draw calls but what if I’m using the same textures throughout the map? Would it make sense for each room to share the same materials?