Actually I am making (at least trying xD) port of one X360 game. It has already generated .dds lightmaps for every environment. I found how one guy made an importer (for Unity) for these maps. Of course I couldn’t find any information how to do the same thing (not just in UE, but any available game engine).
So, it would be nice if someone could at least explain the lightmapping process and tell me how I can control that: give me some documentation or something, I don’t know.
P.S. An example of pre-generated lightmaps: