slightly off-topic, but not really. Have you been watching the progress of 3d scanning technology? Its absolutely amazing how quickly a point cloud can be generated with a 3d scanner set up in a couple of locations. The point cloud can then be imported to the CAD software of choice and be used as as-built information.

The cost is still out of range for me, but its dropping. I can't tell you how many times I've driven for several hours to do a measure up, then realized I'm missing a critical dimension when drawing it up. I then have to drive out again or try and figure it out without. If I had created a point cloud from the laser scan, I could just measure the points from the comfort of my desk.

http://www.autodesk.com/products/recap/features/recap-pro/all/gallery-view.

Autoesk claims that you can also create point clouds from photographs with their 123D Catch and Recap software, but all of my attempts have been subpar at best. Maybe the tech will get better, but in the meantime I'm still salivating over the laser scanners.

Next marry up the tech with a quadcopter and you get this:

http://www.smartlab.at/autonomous-flying-drone-creates-a-3d-map-of-a-building/