Black line around edges once lighting built.

Development Rendering
1

Hi,

Anyone know what is causing the black line around the edges of the room?

The meshes fully overlap so it’s not a light leak.

Any ideas appreciated.

Thanks.

2

This is likely caused by light bleeding over from adjeacent UV polygons.
Either the polygons are spaced too close to each other or the lightmap resolution is too low; probably both.

Also the meshes overlapping might be the cause of this bleed.
Covered portions of the wall mesh, covered by the ceiling mesh, will receive no lighting, causing the transition to be sampled as a gradient.
Depending on the lightmap resolution the gradient may be wide enough to bleed into visible parts of the polygon face.

So: Give the UV islands more spacing and/or increase the lightmap resolution

3

Also, Sometimes just intersecting them through each other with no regards to snapping, causes worse bleeding. Try to snap the meshes together on the grid and make sure they match up perfectly.