[RUNGSI]

Yea I do the same thing.
map out the area, transfer over just the area. then build my structure.
then once finished i can transfer it back and everything fits without moving it.
if the area is differant.
I select the prefab.
goto open the map and it will copy.
once map opens. give it a few seconds. let memory catch up. or it will crash on you.
set the prefab as structural. SAVE map
then i will select the prefab and move it from there.. so if it crashes. aleast the prefab has already be transfered.