I tryed to find this but couldn’t so I had to ask in new Thread…But I just built a House 45X45X25 feet but I did it in same Meteric system as ue4…BUT when I import it…Its a doll size house to the Hero TTP guy…When I scale the house up big enough for the hero to fit, The house is WAY WAY bigger then 45X45X25…Its like 300X300X400 now 
What can I do?? OH and my hero Walks thru the walls, The house is like a ghost??
1 unit in the engine = 1 cm, just scale your house to 1 371 cm.
For your house to not be a “ghost” you’ll need collision, this can be set up in the static mesh editor in the engine or within your 3d application.
thank you Sitrec.
LOL Bro I just saw that video LOL Working on it now… I have a new problem now tho…When I exdrude and fill in the openings that makes, It shows solid in blender but when it gets into UE4 it shows up NOT filled…What am I missing?
Could you send me the blend file, because atm I dont exactly know how you did it ^^ -> you can also make something solid with the “solidify modifier”
Not sure bro. Worked 4 days on it now…Sending to you Bro , Thanks 
I personally would recommend you to:
-re-create the building in blender (this time with solid cubes) -> ?v=URnVMKq7ciQ
-create the building with bsp brushes and then convert it into a mesh
-separate (Space - separate - Selection) the solid parts from the non-solid parts and then add a solidify modiefier to them
But I would just re-create the building, because for this simple shape it has too many vertices + the point 3 would take too long 
