The ability to squash and stretch characters was particularly necessary for the mom character, Helen/Elastigirl, who literally stretches in all directions. Apart from a sequence in which her head was affixed to a boat, "everything she does her character is really capable of doing," says Sayre. "It starts with physically motivated behavior-- you break every bone, give her some more bones, stretch the thing out. But it was hair-raising."
Speaking of which, the characters' hair was another challenge entirely, particularly the jet-black mane of teenager Violet. It was simulation department's job to get it right, "Not to confuse simulation and animation, the hair was simulated, which means the computer is figuring out where the hair goes. An animator is not actually doing that," explains Sayre. "Every hair on your head influences every other hair. This hair is rubbing against that hair which is rubbing against that hair. It was a tough nut to crack."
Violet, an insecure teen who hides behind her hair, "was impossible until stomach-turningly, terrifyingly late in production," recalls Sayre, who began working on the problem before "Monsters Inc." was even in production. "Violet wasn't working until the end of last year, but I never suggested we cut it. It wasn't like we said, 'Let's raise the bar and make a character with long hair.' Everything we did came from the story." However, some cheating was sometimes necessary, Sayre admits. "Violet's part moves from side to side depending where the camera is. Sometimes you do have to read the eyes."
The characters' faces posed another problem: How do you make them seem alive but not literally realistic? "These are superheroes," reminds Sayre. "They don't have pores and blotches." And since they're not based on real people, "We didn't have a photograph of a face to fall back on." It was important to simulate light properly and get the eyes right, he adds.