I have seen one of these machines in action at a show in Dallas. I talked with the guy at the booth for a little while and this is my understanding of what he explained to me. 
He called it a 3D printer. BTW he was selling the software, the machine, and a service that if you didn't want to buy either then he would make the prototypes for you. The software was $6000 and the machine was around $60,000. 
He would open a small door on the lower left of the machine and put in a container of what he called a wax based material. The machine would heat up the material to a liquid. Once the file had been sent from the computer to the machine the print head which was hanging above (but very close to the plate where the part would be made) would begin to sweep back and forth. On each pass of the head small jets would deposit a small amount of the wax where it needed to be to make the part. As the part built up the head would retract little by little until the part had been completed. After the part came out he would have to use a small needle to cleanup some of the smaller cracks. This particular machine did not use any lasers or UV light. He also said the wax could not be reused because of contamination after people touched the part. I don't know if this is the same machine that you are talking about but this is how the one that I saw worked.

Troy Powledge
TCo. Systems
tpow@eramp.net

-----Original Message-----
From:   Randy Walsh [SMTP:randyw@COLUBS.COM]
Sent:   Monday, July 14, 1997 5:43 PM
To:     PICLIST@MITVMA.MIT.EDU
Subject:        solid model proto-type fabrication

I read in this months Popular Mechanics about a company that sells a device
which creates sold model prototypes.  As far as I can tell, a container is
slowly filled with an epoxy compound, which is hardened, layer by layer, by
some sort of laser.  The result is a 3-D epoxy model.

This is a really neat way to create stuff  (By the way, they want a modest
$99,000.00)  Does anyone have any idea about epoxy's, or other compounds
which can be harden by laser?  How about UV light? or other methods which
can be computer controlled?


TIA
Randy
walsh@writeme.com