Now this is interesting. I think this would be an amazing tool to use in the initial conceptual phases of architectural design. I'm excited to see where HP takes this.
Also of note, but not shown, is a new 3d printer that HP that developed that they say can print 10x faster than today's technology. You can see more case study videos and a very cool, very Apple-ish even, video here.
Update: There's an article on HP's new 3d printer here.