Needless to say, all of the model characters are unique - and thus it's very appropriate to produce them (or rather many of their component parts) on 3D printers. Pictured is Coraline with her snap-on mouth removed.
Where's her mouth? It turns out that the Mount Everest of CG is facial expressions, and the snap-on mouth is a method of approaching that problem by being able to rapidly experiment with a wide variety of subtle mouth shapes, again using 3D printing. How many? Apparently they ended up with 15,300 different face modules for 21 unique characters.
Where did we put that cheesy smile again?