These videos show you how you can build a 3-D laser scanner using a line laser, web cam, your desktop/laptop and some free software:
How to make a 3D scanner (quick overview)
Duration: 6 min 33sec
Systm – Episode 73 – Build a 3D Scanner From for $25 (getailed walkthrough)
Duration: 39 min 57 sec
In the video from the guys at Systm, Patrick just moved the laser line by hand. The following videos show people who have set up rigs with stepper motors so they can have finer and more reproducible control of the line lasers movements as scans are being made.
3-D Scanning Software: David Laser scanner. The basic version of the software is free.
A few pointers, I tried the software with multiple webcams, it worked straightaway only with logitech model quickcams. Other webcams required much faffing around and searching the forums.