Why are you so against it? It IS much more work, you don’t want to listen, that’s all.
Unity is already doing that without any problems and works like a charm! So why UE4 can’t?
I don’t want to argue with you, I just want to give an idea, since this is problematic for the arch viz artists, for who the lighmapping is one of the most important features.
And what about smoothing groups and visible seams on lightmaps then? This IS a problem on bigger surfaces!
And what part of: “It’s like literally importing one model four times, just because i cannot split lightmaps” you didn’t understand? I’m doing separated UV’s for EACH ELEMENT ANYWAY! So creating polygon IDs is taking few seconds more.