This is something that has been done in the granite industry for many years. Check out this link http://www.carterproducts.com/produc...id=16&cat_id=7 I have used these systems before. There is a reflector at the four coners of the table that are used as a reference for the laser to auto adjust to the table. You set up your cam system to output a 2d dxf file that projects down onto the table and align your parts to the projected file. The laser can be scaled and moved for accurate alignment. The only drawback is that the laser has a hard time projecting really complex parts. To combat this you just project the geometry needed to reference your parts.