Joystiq

Perlin uses different interface switchers to move around parts of her face, and then shows that by conjoining movements, a programmer can create emotional "chords." He illustrates this by tightening her lips, half-closing her eyes, and cocking her head back in one direction. The effect is convincing: she looks displeased. Perlin's work on emotional chords has played a large part in the emotive facial responses of characters in Valve's Half-Life 2. In fact, his real-time model is almost a dead-ringer for Alyx.

Perlin goes on to discuss the increasing importance of emotion in games. He cites the example of Facade, which he says "takes the level of psychological violence much further than shooter games... I kept saying to myself 'I'm so glad this isn't a real dinner party.'"

Perlin then shows the audience the simplest character that can be made to portray emotion. Her name is Polly, and she's only five polygons. Polly displays emotion with limited movement, like scampering, swaggering, prowling, lumbering, feeling dejected, hotfeet, sprinting, and hopping. According to Perlin, we should refer more to people's own "database of emotional knowledge," playing into expectations and letting the brain do the rest. The anithesis of this is Final Fantasy: The Spirits Within. "Don't get me started on Polar Express," he says, shuddering. He asks us to contrast this hyper-realism with a Bugs Bunny cartoon. Bugs Bunny, as a character, is believable, but "that's not the same as realism. If Bugs Bunny walked through that door, people would freak out."

He shows some more demos, the next one of two emotive virtual actors, with full-body awareness of actions. When Perlin grabs the actor's hand, the actor's entire body reacts: the feet move, the hips swivel, etcetera. Perlin considers this "full-body awareness" important to in-game animation: "the reason that all game characters are unbelievable... is because of what happens from the waist down."

His response to this is several experiments in footsteps. One applet is designed to make "smart feet." Perlin says that "we are, in our minds, magical floating heads and hands." We don't often think about the rest of our bodies, he explains, so it's hard for us to animate convincing people. In each example he shows, he focuses on creating convincing foot movements.

After a few more examples, Perlins begins to wrap up his keynote. In closing, he explains that "people care about the emotions of people... We can do things they can't do in the film world; we can go beyond film, but our techniques are much younger."

"The Graduate is a mindfuck," he says, then stops and asks "am I allowed to say that?" The audience laughs, encouragingly. "Well, anyway," he goes on, "we want [games] to be that, interactively."