In this video (check the source link), a BBC reporter explains about the three types of 3-D printers that are used in this particular prototyping lab. There’s a printer that uses a powder substance, which is injected with glue to form three dimensional figures. There’s also a printer that uses a type of resin, which requires it to make additional calculations about where to “support” the figure during the drying process. The third printer actually prints out of paper, creating a 3-D structure by slicing a ream of paper at predetermined intervals.
It’s good to know that 3-D printing is being used for something other than creating custom World of Warcraft avatar replicas.