If we are talking this house, we know the rooms, the interior walls are "printed" at the same time as the external walls. It has a vestibule (entrance hall), washroom and open concept room that is used for everything else.





now if we are talking in general, I agree some people might over do it with the idea of "it is not the normal box so I don't want any walls that are 90^o


but they don't need to and you can have 90^o walls and rectangular rooms if you want