How they made the critters in Over the Hedge.

Over the Hedge, an animated feature about a gang of wild animals that becomes addicted to junk food, earned more than $37 million at the box office last weekend. The credits for the film list several dozen "animators," five "character effects animators," three "supervising animators," and two "character animators." How does an animation team work?

One department designs the characters, another makes the computer models, and a third animates them for the screen. First, the art department draws up sketches or constructs models of the characters in the movie, in collaboration with the director and the producers. (They'll also come up with ideas for sets and props and for the visual style of the movie.) Once the artists finish the basic designs, they pass the characters on to the technical team.

Technical directors convert each character into a 3-D computer model that can be manipulated in predefined ways. The technical team sets up the moving parts for each character and turns it into a virtual puppet for the animators. In general, each technical director works on his own character or in a small group devoted to a single character.

Next, the animators act out scenes or shots by positioning the puppets in individual frames. Sometimes they'll act out the scenes themselves to get an idea of how the characters will relate to each other in space. Senior staff members establish a particular style of movement for each character so that its body language and facial expressions match its personality. (In some cases, they use videotapes of the voice talent to generate ideas.) The top animators also establish guidelines for the overall aesthetic of the film. For example, they could decide to let the characters change their body proportions as they move; they might stretch out when they reach for something, or flatten to a pancake when a piano falls on their heads.

If the animators discover that the puppets aren't working right, they'll send them back to the technical team for a tuneup. Meanwhile, the director and the supervisors keep an eye out for inconsistencies: A single character will have its strings pulled by many different animators over the course of production, so it's important to make sure that it's always moving and behaving in the same way.

For a movie like Over the Hedge, the animators set up only the frames that define the key moments in a given action; the computer fills in the rest. In conventional two-dimensional animation, senior animators draw out the key frames and pass on the "inbetweening" work to the rookies. Animated television productions often contract out the inbetweening to studios in Korea.

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Explainer thanks Rob O'Neill of the Pratt Institute.