The first two installments of The Lord of the Rings trilogy, The Fellowship of the Ring and The Two Towers, showcased stylized environments and creatures created with myriad techniques, ranging from in-camera effects to computer animation. Of special note are the eerie and emotionally convincing Gollum character, the crowd animation system and the superb digital color timing.

Cartoon and realism come together in Hulk. © 2003 Universal Studios. All rights reserved. Credit: ILM.

Cartoon characters in a live-action movie belong to a genre that goes back to Hollywood movies from the 1940s. Some of the most notable examples of this style include movies where the virtual characters are a unique mix between cartoony and realistic. Think, for example, of the amusing slapstick comedy of Mars Attacks! (1997); the wackiness of the Men in Black (1997) space aliens; the charm of the half-realistic half-cartoon characters in Stuart Little 2 (2002); the hyperrealism of the simulated wet cloth and wet fur, as well as the drama and comic book larger-than-life qualities of Hulk (2003); and the dark and gory humor of the ghost pirates in Pirates of the Caribbean: The Curse of the Black Pearl (2003).

The Future of Virtual Characters
As productions get more ambitious, virtual characters will increasingly require that their look and performance are convincing, and that both make sense within the reality of the live-action world. The success of future virtual characters depends on a few key creative and technical considerations. From the production point of view there are several issues and stages of the process that directly impact the characters’ look, including styling, modeling, texturing, rendering and compositing; rigging and animation that influence their overall performance. Rigging, for example, is an issue that clearly demands renewed attention, as a number of recent virtual characters (such as Gollum) required motion rigs that could be controlled by both keyframe and motion capture data. Currently, Warner Bros.’ Polar Express, a movie in production at Sony Imageworks, makes use of extensive motion capture as the main performance driver of virtual characters. On the animation front, the use of simulation software to take care of secondary action is likely to become increasingly necessary to deal with the complexity and enormity of the data involved in animating virtual characters.

Many Agent Smiths appear courtesy of CG in The Matrix Revolutions. © 2003 Warner Bros. Ent. — U.S., Canada, Bahamas & Bermuda. ©2003 Village Roadshow Films (BVI) Ltd — All other territories (All rights reserved used by perm

From the creative point of view, future virtual characters will need to deal with a wide range of challenges in order to be believable. Consistent and frequent interactions with live actors, full mobility and camera framing ranging from headshots to full body shots are some of the important factors on the performance front. Rendering techniques that approximate the subtlety of skin, eyes, hair and fur. The creative and production crews will gladly receive animation controls that streamline the animator’s job. Last but not least, future virtual characters will need to develop distinct personalities that can be as convincing as those of human characters.

Isaac V. Kerlow is director of digital production at The Walt Disney Co. in Los Angeles, California. He is also a longtime active member of SIGGRAPH and the Visual Effects Society.