> If you were an architect with those kinds of clients you would have a list of potential builders with track records of successfully completing similar work.
My point is that you don't have to have this knowledge, and you don't have to hire expert craftspeople and pay them expert wages if you can have a machine do the difficult work.
> And most importantly you would know that right angles are almost always the right answer...
Not necessarily. Box-shaped rooms work nicely, but the most important thing is to not have acute angles between walls. (IIRC Christopher Alexander goes into this in A Pattern Language in defense of right-angle walls, but for some reason neglects to consider rooms with more than 4 sides as an option.) Greater than 90 degrees is fine as long as it doesn't present a problem for the intended use (i.e. client expects furniture to fit at right angles). Also, if you're printing a whole house you can design benches, shelves, desks, and so forth into the design. Or maybe contract out to some service that will make the furniture based on a 3D model.
A big part of why walls are straight and meet at right angles is that building materials are generally straight and expect to be joined at right angles. Anything else turns into a complicated geometry problem that takes a lot longer to build. With a 3D printer, though, that's not a limitation. It doesn't matter how simple or complicated a design is, it takes about the same amount of time to print and uses about the same amount of material. The main constraints then just become what's strongest, nicest-looking, and most functional. Most people will probably prefer box-shaped rooms, but the point is that they'll have options if a box-shaped room isn't optimal.
One could imagine if house-design software becomes sufficiently advanced, you could dispense with the architect as well. Someone who wants a house could just log onto a website, identify the site where the house is to be built, and specify a bunch of constraints and preferences, and then the backend software generates a bunch of house plans. The customer choses the one they like and pay the money, then a building permit is applied for and a printing machine and work crew show up on site and assemble a house that's unique and exactly suited to its site.
