To be fair this is melting media with heat in the rapid prototyping mould. They're just substituting a hot air gun for a laser, so I'm not sure of the coating possibilities.
If of course you can substitute say an airbrush for the hot air gun, and find some way of keepng things hot enough so that you can spray gelatin......
What might be fun is inkjet cartridge, gum bichromate mixture, and away you go!