Photo courtesy Disney The Incredibles features the voices of Craig T. Nelson, Holly Hunter and Samuel L. Jackson.

Photo courtesy Disney

For the creative minds at Pixar, designing and animating the playthings of "Toy Story" and the cute beasties of "Monsters Inc." was child's play compared to what they faced in bringing "The Incredibles" to the screen. This latest effort, an action comedy about a family of superheroes exiled to suburbia, proved almost impossible.

"The biggest challenge is that we were dealing with human characters," says supervising technical director Rick Sayre. "Hair simulation, hair sculpting, clothing simulation and clothing patterning-there's so many components that go into pulling that off. We had the human Al in "Toy Story 2" and little Boo in "Monsters Inc." had hair and clothing, but she wasn't in every shot and she was just one character. Here, we had to essentially invent from the ground up the way we animate characters and rig them."

Rigging, explains 17-year Pixar veteran Sayre, "is how you set the character up, kind of like a puppet or a performance, so the animators can manipulate it and yet it will move in a convincing way. Humans are really complicated. You have bones that float and the shoulder is not even a single joint. To do humans convincingly, you need to essentially simulate the way skin moves over fat and muscle and is driven by bones and slides against bones. That verisimilitude is what tells you it's human and not a puppet or a toy. You also want to be able to caricature. So on top of that we added squash and stretch for each bone--bends and bows where you can change what the flesh is doing."