It would be awesome if UE4 had something that worked as a region render so that we would be able to refine lightmaps and test different parameters only at a determined location without having to wait the whole scene calculation.
Even better if this region render could smooth out with the already calculated lightmaps. This way, we would render portions of lightmaps one at a time with different parameters.
P.S.: English is not my main language. Feel free to correct me.