Neither of the above. Build your house in Max as parts as ryanjon said. Modular is the way to save on all fronts. 1 wall used however many times you need it. 1 staircase, 1 door (most houses have the same door on every room). Then import the parts and put them together in UE4. Using the box brush is wasteful, it’s just for blocking things out and not very efficient. Using a giant mesh will result in a mess as UE4 won’t be able to figure out things like collision properly (Is the entire house a collision object? Are the separate parts collision objects? you get the idea) - then there’s texturing, I can’t imagine the pain it would be to try and texture an entire house for a game engine. You would need like a dozen material slots. And that’s even with no furniture! LOL No just build a floor, or a floor segment (with a few materials), a wall segment, a few doors, a few windows, some steps. Bring them in and start making like it’s a lego kit. It’ll always work right because a wall segment is just a box, etc.