A Pixar film is a beautiful thing. Long after Toy Story‘s 3-D novelty wore off, artists refined their techniques, so Up could make us cry. But in these computer-generated worlds full of perfect shapes and gradients, we inevitably lost some of that old Disney magic–the nuance of incredible, hand-drawn lines. “Isn’t there a way we can bring that hand of an artist back?” John Kahrs thought.

At the time, he was working on his storyboards for Paperman–what has since become Disney’s 2013 Oscar-winning animated short. It was going to be “an urban fairy tale in a beautiful world of light and shadow,” showcasing the latest in CG technology like global illumination and radiocity (light-based physics). But another thought had been haunting him. Working on Tangled alongside legendary 2-D animator Glen Keane (The Little Mermaid, Beauty and the Beast), Kahrs watched Keane sketch on top of the CG animations during the production process. Software allowed Keane to reshape 3-D figures with his pen strokes, but ultimately, his beautiful lines were lost in the process. It seemed like such a waste.

Late in the storyboarding process, Keane’s vision for Paperman was born anew. What if it could be a hybrid of the old and new schools of animation? What if it could be 2-D and 3-D at the same time?

Editor’s Note You can see all of this years Oscar-nominated short films at Co.Create.

Kahrs began investigating that possibility in the only place he could, Disney’s R&D department. He lucked out when he met software engineer Brian Whited, who had already been working on a new piece of animation software called Meander that specialized in 2-D interpolation (using software to reason out gaps in sketched animations). With modification and refinement, it just might work.

“You hear people talking a lot about innovation–innovation comes out of necessity,” Keane says. “The necessity in this case was we had to figure out how to have a CG underlayer that dragged these drawn lines on top of it.”

Eventually, Meander proved capable of stunning feats. Today, an animator can draw a frown on a protagonist’s hand in one frame, then, several frames later, draw a smile. Meander can both track the position of that hand in 3-D space, and it can fill in the gaps, turning that frown into a smile, naturally. But much of Keane’s emphasis was tweaking the feel. In classic Disney animation, the character outlines do something called boiling, as the imperfections in cel after cel stack up–and they’re important, subconscious cues to the experience of animation feeling authentic.