The previous discussion from Oct '13 (https://news.ycombinator.com/item?id=6628137) on these guys : http://www.industrytap.com/the-printer-that-can-print-a-hous... suggested an interesting powerful way of creating buildings. Looking at the article it appears this guy prints a concrete tube and then tilts it over on its side and puts windows/doors on either end. That seems to me to greatly restrict his complexity choices.