Lighting Problems (Shadow on every modular piece)

I have some serious lighting problems. I put together some basic modular stuff from the starter content to try and fiddle around with lightmass.
But already with basic lighting I get these weird looking artifacts. Is it intentional that it looks that ugly from the start?? Why is it baking shadows at every modular piece although there should be no shadow?

Got only one static light, no sky, no sun. No changes made to lightmass settings or ini.
Lightmap resolution: Walls = 128, Floor = 512, Cube = 32

Can someone help please?
Thanks a lot, I’m despairing


i think it’s a uv problem

Thanks for the answer. I put only some starter content in, guess that should be perfectly UVed?

Edit: I looked through some videos and found this one
which seems to be the problem I’m facing, because when I rotate the asset, the black marks are rotating as well.

Thanks for the tipp with the UV.

Ok, now I fixed the Lightmap UV Problem, but facing another problem with the different colors of each tile.
Someone can help me on this?
Thanks very much.


I believe this effect can be minimized by ensuring your lightmap uv island edges align to the edges of the grid.

Merge all modular pieces in one mesh, otherwise you’ll get visible seams in any case. But with some lightmass setup you’ll be able to reduce artifacts even for separate meshes. It was discussed earlier [bug] Lightmap color continuity issue - UE4 AnswerHub

Thanks very much for these links. They helped me alot to understand the problem. Though it does not solve my issue with the modular walls. Thanks for the valuable help.