I am building a house interior in Maya and importing it to UE4.14. I created the uv lightmap in maya and did a lighting build with quality high, but I see alot of uneven shadow artifacts. see below
your lightmap resolution is too low
But the other issue is that you need to make sure that walls/floors/ceilings don’t extend beyond each other, the surface outside of those edges will receive shadow or light which will bleed onto the inside.
One more possibility could be that the Lightmap UVs aren’t setup correctly. For walls and the like, you should be splitting UV islands at places on the meshes that are close or equal to ~85/90 degrees (Depending on who you ask.)
For people stumbling upon this, you double click on the imported object and increase the light map resolution to a Power of 2 number. 64, 128, 256, 512, 1024, etc.