The image above shows two photos of the same pile of rocks but taken from slightly different angles. The 3D mesh below the photo was extracted from the two 2D images using a smart stereographic software application called PhotoSculpt (http://www.photosculpt.net/).
I knew there was always going to be a challenge getting 3D laser scanners to work on building sites because of their expense and the damaging environment they would be in. PhotoSculpt came out in 2010 and, combined with cheap and robust digital cameras, provides a very cheap method for acquiring and updating the surface of the working face of a seawall or building under construction.
Another good and cheap application for acquiring 3D data from 2D images of an object is Pictomod3d (http://styxar.com/ptm3d.htm) which came out in around 2004. It generates a complete 3D mesh of an object from a number of 2D images of the object as it is being rotated on a turntable. The image above shows a rock and its corresponding 3D mesh generated by Pictomod3d.
3D laser scanners might be useful for generating very high resolution data but for building with rough rock, applications like PhotoSculpt and Pictomod3d combined with cheap digital cameras could do the job.