Paperman - animated short film

its a 2D and 3D hybrid . but the finished result is a 2D animated movie. hard to explain.
http://en.wikipedia.org/wiki/Paperman

here is the making of video.
http://www.itsartmag.com/features/paperman-breakdown/#.UGwI2FFb6U8
http://www.youtube.com/watch?v=-eHhExk9S0E

they animate a simple 3D character. then a 2D drawing artist draws lines on top of the 3D model. but its not in 3D space. its in 2D space . the custom software anylizes the lines and helps the 2D artist to draw in 3D.

Paperman was screened at siggraph. rumors are that it could be one of the best disney short movies.