Visit Merlin at HP Palmtop Tour.



Visit MIRALab at the University of Geneva.


























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Just Act Natural

by John Dudley Miller

If you're one of the many people who aren't yet sure what synthetic actors are, let me give you a hint. You probably have seen them. In the movie "Titanic," some of the extras huddled on the deck of the slowly sinking ship were synthetic actors, computer-generated characters realistic enough to pass for humans. Fooled you, eh? And to think you cried such big tears over them.

You've seen another kind of synthetic actor if you've ever looked at the website for Hewlett-Packard's Palmtop computer. A cartoon-like version of Merlin the magician is just human enough to answer your questions while he explains the new machine's features. He can make 60 different gestures, and he responds appropriately even to messages off the subject, like "What time is it?" or "Say hello.".

The first widely-viewed synthetic actor was a virtual version of Marilyn Monroe, created a decade ago by Nadia Magnenat-Thalmann and Daniel Thalmann, the ground-breaking husband-and-wife professor team in Switzerland. Clips of the digital version of America's greatest heartthrob have played on TV stations around the world. Their 1987 book, Synthetic Actors, gave this emerging field its name.

These days Marilyn would be categorized as a special kind of synthetic actor, an avatar. Popular with web gamers, avatars are characters that represent the real people controlling them in a virtual environment. The term comes from the Hindu name for the several different human forms the god Vishnu took on when he appeared on Earth.

According to the SIGGRAPH 98 program, synthetic actors are the end result of "creating, acquiring, programming, and controlling realistic, real-time human behavior," like Marilyn sashaying or the "Titanic" extras pondering blue-lipped death in cold cyberwater. But the ones being discussed and demonstrated in Orlando actually stretch that core definition in two important ways.

Visually, this year's models run the 3D gamut from cartoon characters to realistic depictions of humans to artificial life objects, imaginary creations whose only limits are that they must follow basic life processes like evolution, breeding, and natural selection.

In terms of behavior, this year's synthetic actors range from brainless, totally controlled renderings like those found in traditional cartoons, to characters equipped with such powerful intelligent agent programs that they act autonomously, adapting to a variety of situations.




Modeling | Rendering | Animation | Interaction | Virtual Reality | Synthetic Actors