As moviegoers, we have all seen a wide range of animation—from early Disney features, such as “Snow White,” to Japanese anime, and Pixar’s “Toy Story,” to an assortment of recent blockbusters that seamlessly integrate animation with real actors. With each release, the movie magic gets more amazing as animated characters such as the Incredible Hulk or Gollum in “The Lord of the Rings” take on lifelike qualities and realistic human facial expressions. How in the world do filmmakers do it?

As animators know all too well, the human face is one of the most difficult objects to realistically model. A flexible layer of skin covers a complex array of muscles and bones, producing a seemingly endless number of subtle facial expressions that are an important component of our communication system. Technology that allows blending live-action with special effects has pushed the animation field into realms hardly imagined just a few years ago, as animators use computer-based physics in much the same way that design engineers use realistic simulation.

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