[Galun]

I come in here a bit late, but I do building models in several meshes because I want to be able to open doors, go in and look out of a window. For me it was easier to build a house with a base block, walls, ceilings and a roof. The doors are movable so they have to be a mesh on their own anyway.
For better performance I built simplified versions of the models and these are done using a big box and only some of the details. The simpler models replace the detailed ones at a certain distance to save rendering time.