transparent part

hello,

i have seen this website (rapid prototype machines), and it looks like they are making really transparent parts (pmma).
does anybody know about it ?

http://www.stratoconception.com/index.php?option=com_content &task=view&id=90&Itemid=170&lang=fr

I don't read the language, but it looks like they cast the transparent parts from a temporary mold

Very strange. I read the language and my understanding is that is is not 3D-printing. It is more laser cuting of different individual layers that are then assembled.
How they go from this set of layers to a transparent part is... unclear.

They cut many slices in PMMA, then glue the slices. With proper care to avoid contamination and the right glue (solvent, not typical glue), the joints are transparent.

here is an explanation of the process

http://www.stratoconception.com/index.php?option=com_content &task=view&id=21&Itemid=84&lang=en