With 3-D providing greater attention to detail, the animators were tasked with making facial and fur tweaks.

Dealing with dinos for the first time was certainly a challenge for Blue Sky animators. According to Chu, the riggers came up with a new way of skinning characters, specifically for the dinosaurs, "so that we could get the fleshy look we were going for and to get the muscle jigglers to feel like they were really moving off of bone underneath. It's not quite a muscle system per se, but simulates the effect.

"And definitely with our new character, Buck (Simon Pegg), I think they came up with some really neat features that I've never seen before in any of our other animated characters. I guess it's closer to what we did on Horton Hears a Who! Since he was a tall, weasel-like, flexible character, we wanted to push that design feature and get as much as we could out of it. In one shot he literally rung himself like a wet towel to dry himself and that's a special case in a rig."

And when it came to tweaking Diego, they added a few small details that Chu thought were missing on the last Ice Age. "For instance, we added some cheek movers on Diego to engage that area of the face more. I think the fur group added some extra handles to improve the grooming and look just a bit."

Scrat has been given a love interest, Scratte, to complicate his ongoing quest to horde his acorn.

However, in embracing Scrat's new love, Scratte (Karen Disher), they got to experiment even further. "The direction on that one was that she's definitely a smarter, sleeker version of Scrat. He should always be a step behind and her and just with that information, the animators could come up with a lot of situations where she's [the victor at his humorous expense]. In terms of movement, we wanted to make her more refined and elegant. And from a fur standpoint, they made sure that she had a nice sheen to her that shows how much she grooms herself."

And even as an animation supervisor, Chu was able to exert a personal influence on the quality of the work. "One of the challenges was, because of our schedules, we've had to bring in around 35 temp animators [raising the department total to 75], train them and get them to perform at a level that we feel good about. Training these new animators, whether they were freelancers or recent graduates, was part of my responsibility, and I hope there is a consistency to the quality of the work and that you can't tell a difference in levels of experience."

Bill Desowitz is senior editor of AWN and VFXWorld.