Technology has evolved really fast. Before, there was only 2D scanning and reverse engineering was done by just approximations. Then, there was this stuff where you could actually measure the x, y, and z points by using a probe of some sort. After that, when I was in college, a group made a thesis of an oven-type 3D scanner. The latest technology that I saw recently from the Manufacturing Technology World 2006 is the 3D scanner from ZCorp which is a handheld device that makes use of laser gun that is connected to a computer. All you have to do is to put the reflective stickers on the object that you want to scan and start scanning.