Aki in Final Fantasy looks quite human, but the illusion dissolves when she moves and talks. All Final Fantasy images © 2001 FFFP All rights reserved.

Animation has its wall, much like the sound barrier -- difficult to get past, but theoretically possible. It happens when our 3D-animated humans start to look too real. You'd think the more real a character looked, the more believable it would be, but just the opposite is true -- to a point. Before you reach the threshold of believability, you have to travel through the "Uncanny Valley."

Robot designer Masahiro Mori coined the expression "Uncanny Valley" way back in 1970. He was referring to the seemingly inexplicable plummet in credibility of robotic characters as they approach a certain high level of realism. In other words, the more real they look the creepier they make you feel.

Interestingly, Sigmund Freud discovered that his patients often described an uncomfortable feeling when something was both familiar and unfamiliar at the same time. He called it "the uncanny." It happens when a person holds two or more conflicting beliefs, emotions or feelings at the same time. Of course, this is where cognitive dissonance comes from. For example, when a virtual human actor looks very, very real, you want to believe it is real, but a subconscious protective mechanism in your brain starts looking for flaws to prevent you from being fooled.

The result is simultaneous belief and disbelief. Movies are all about suspension of disbelief and this kind of dissonance disturbs that process -- ditto for games.

Think of it this way: most animated characters are not trying to fool you. They are what they are, but when they start to look too human, they're trying to fool you and your subconscious is wary of being fooled. The result is a nagging feeling just below consciousness that prevents clean suspension of disbelief. At some point, when we get nearly everything right, we'll be able to again believe. For now, consider such iconic characters as Robbie the Robot or Homer Simpson. With them there is no cognitive dissonance. We understand and accept them because there is no pretension.

On the other hand, Aki Ross in Final Fantasy inadvertently comes across as pretentious: a cartoon character masquerading as a human. As she moves, our minds pick up on the incorrectness. And as we focus on her eyes, mouth, skin and hair, they destroy the illusion of reality. Adding a voice we recognize (Ming-Na) only complicates matters. Thus, we identify Aki Ross in too many incompatible ways simultaneously and our brains can't handle it. But more about Final Fantasy later.

Even with its flaws, Dr. Parag Havaldar finds that Beowulf shows how far performance capture has come since Polar Express. All Beowulf images © 2007 Paramount Pictures and Shangri-La Ent., LLC. All rights reserved.

Crappy MoCap also kills the illusion every time, so care must be taken on the body, but most especially on the face's emotional zone. It's roughly a circle that goes from the bottom of the chin to midway up the forehead. Side to side, it's the entire width of the face. If we get that right, most of the audience will forgive minor errors in body language... but don't push it. Theoretically, at some point, we can create a character so real in looks and behavior that most people will accept it as real. That's the goal.

It's very expensive and time consuming to capture all the paralinguistic nuances that make up a performance. According to Dr. Parag Havaldar, lead software engineer on Beowulf, "[The Robert Zemeckis film] is an awesome accomplishment when you think about it. It's a 100% animated film with many digital bodies and faces exhibiting believable realism. Sure there are flaws when you compare it with real actors, but we've come a long way since Polar Express. We used advance techniques to capture eye movement and detailed face movements using our ImageMotion technology." He added that Sony Pictures Imageworks had more than 14 terabytes of performance capture data to filter and tweak.

Still, the level of keyframe tweaking was not always what it could be. For example, I noticed in one of Anthony Hopkins' performances as King Hrothgar that the actor exhibited many subtle mouth and facial expressions that were not picked up by the performance capture equipment. Several layers of nuance were added by hand, but something was still missing. We're talking very subtle. For example, he had a subtle, nasty little smile that held so much meaning and some of it is missing in the final print. That tiny bit of smile apparently held a lot of emotional information, because I could feel the difference. "It is not a procedural process and we're making good progress, but the amount of hand tweaking that would have been required to enunciate all subtle expressions on every character in a movie this scale would have been expensive.