Disney's Paperman won the Oscar for Best Animated Short Film Sunday night, marking a triumph not only for the studio, but for hand-drawn animation — a medium that seemed to be nearing extinction thanks to the rise of Pixar CG marvels like Up and Wall-E. But as director John Kahrs explained in an interview with Fast Company, Paperman isn't just an homage to the animated films of yesteryear; it's a testament to how modern technology can breathe new life into analog formats.
According to Kahrs, Paperman was originally conceived as "an urban fairy tale in a beautiful world of light and shadow" that would deploy global illumination and other cutting edge CG technologies. Things slightly changed, however, once Kahrs began working alongside Glen Keane, a renowned 2D animator whose previous credits include Beauty and the Beast and The Little Mermaid. It was Keane's influence that inspired Kahrs to turn Paperman into a hybrid of 2D and 3D animation — a blend that would appropriately reflect the film's nostalgic aesthetic. The only challenge? Finding the technology capable of pulling it off.

Kahrs eventually found the answer at Disney's R&D department, where engineer Brian Meade introduced him to Meander — software that automatically smooths out any gaps or hitches in traditional 2D animation. If a character's face goes from frown to smile, for instance, Meander will track her face in 3D space, making the transition appear more natural onscreen.

Source:
http://www.theverge.com/2013/2/25/4026968/making-of-paperman-disney-oscar-winning-animated-short-film

For video:
http://www.youtube.com/watch?feature=player_embedded&v=TZJLtujW6FY