Gadgetopia

I saw something similar to this in action several years ago; it used a vat of a liquid polymer that hardened when exposed to a high-intensity light. I think it used a low-power laser, and basically "imaged" milimeter thick layers. It started with a platform just below the surface of the polymer, and the platform would drop down with each imaged layer. It took a couple minutes for each layer; a couple hours for a fairly small object. The surface was a little on the rough side -- they were working on higher resolution. I thought the same principal could be applied on a larger scale, using a quick-dry cement to lay out building foundations or even exterior walls for taller structures. It'd take a fairly substantial framework to support the "imaging" end of things, but it could be driven by a run-of-the-mill PC just like a plotter. Only bigger. So many ideas, so little time, so little capital.

Wired has a bit on this:

http://www.wired.com/news/technology/0,1282,59648,00.html

I saw one of these in action on a great History Channel series called "Modern Marvels: Building a Skyscraper" (great, great show for any architecture or construction geeks out there -- it's a series that continues tomorrow):

http://www.historychannel.com/modernmarvels/

They showed a printer making a rendering of the new CalTrans building in Los Angeles:

http://www.clark.constructware.com/ProjectProfile.asp?PrjID=23367

It was interesting -- the print head essentially just lays on ink (not ink, actually -- a power-type substance) really thick, then drops the print surface a fraction of an inch and does another layer. Eventually the form "grows" out of the surface.

The finished model was a little...gray, but I assume it could be painted. From what I saw, it appears to take a long time to render a little model of a building, so you're not going to whip these out as fast as a Word document draft, but still pretty handy, I imagine, for architects and engineers.