CMU / DRP

At left, a subject wears an array of 20 strategically placed cameras, facing outward to monitor apparent motion in the environment. At right, the data from all those cameras can be interpreted to produce an animated figure in virtual space.

Motion-capture animation is all the rage in moviemaking: Without it, there's no Gollum in "The Lord of the Rings," no aliens in "Avatar," no intelligent chimps in "Rise of the Planet of the Apes." But it's an expensive proposition: You need to place special dots all over the actors whose motion you want to capture, then have them do their thing in front of precisely calibrated cameras hooked up to a sophisticated computer system, inside a closed stage with controlled lighting.

Now all that could change, thanks to a new system that relies on cameras looking out from the actor's body, rather than cameras looking in at the actor.

"This could be the future of motion capture," Takaaki Shiratori, a postdoctoral associate at Disney Research, Pittsburgh, says in a news release about the technique. "I think anyone will be able to do motion capture in the not-so-distant future."

Shiratori presented a paper about the inside-out approach to motion capture, known as "structure from motion" or SfM, today at the ACM SIGGRAPH 2011 conference in Vancouver, Canada. The method has been the subject of research for 20 years at Carnegie Mellon University and Disney's research facility in Pittsburgh.

In traditional motion capture, cameras focus on dots that are placed at strategic locations on a body suit worn by the actors. Computer software renders an animated image — the chimpanzee or the alien, for example — so that its movements conform to the positions of the dots. That animation can be substituted for the actor's image in a computer-rendered composite.

"In 'Avatar,' motion capture was used to animate characters riding on direhorses and flying on the back of mountain banshees," Shiratori and his colleagues write in the paper. "To capture realistic motions for such scenes, the actors rode horses and robotic mock-ups in an expansive motion capture studio requiring a large number of cameras."

In the SfM version of motion capture, 20 lightweight cameras are mounted on the limbs and the trunk of each actor, looking out into the environment. As the actor moves, the video from each camera is compared with reference images, and translated into the movements of the animated figure in a virtual 3-D environment. No studio needed.

The good news is that the technique can be used to capture a sequence of movements in an outdoor setting, with no boundaries on the range of movement. This video shows how the software builds a virtual space, sort of like the data-point cloud created by the Kinect motion-detection game controller, and tracks an actor as he moves through the space.

"Our approach will continue to benefit from consumer trends that are driving cameras to become cheaper, smaller, faster and more pervasive," the researchers write.

The bad news is that rendering the imagery currently calls for a huge amount of computational firepower. The researchers say it takes an entire day to process just one minute of motion-capture data, and the final results aren't quite as good as what's achievable through traditional methods. But as Gollum said in "The Lord of the Rings" movie, "Patience! Patience, my love." The researchers hope that precioussss innovations will soon be within their grasp.

"Future work will include efforts to find computational shortcuts, such as performing many of the steps simultaneously through parallel processing," the team reports.

More on movie tech: 

• Virtual actor takes over in 'Tron'
• The physics behind the movie magic
• The future of 3-D moviemaking
• From 2002: Brave new world for virtual actors

In addition to Shiratori, collaborators on "Motion Capture From Body-Mounted Cameras" include Hyun Soo Park, Yaser Sheikh and Jessica K. Hodgins of Carnegie Mellon University and Leonid Sigal of Disney Research, Pittsburgh. Hodgins is a DRP director as well as a CMU professor.

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One of the best things about virtual reality is that it isn't real — and the Pentagon is taking advantage of that fact by offering a virtual realm that can take combat vets and their loved ones through the whole cycle of post-traumatic stress disorder.

PTSD and depression are thought to affect 10 to 30 percent of the U.S. military personnel returning from Iraq and Afghanistan, depending on how you define the disorder. For some vets, the trauma left behind from combat experiences can lead to alcohol abuse, aggressive behavior, family problems or even suicide.

Typically, therapists help PTSD sufferers get through the experience by having them relive and talk through stressful experiences in a safe environment. That's where virtual reality can make a difference: For several years now, therapists have been using online worlds such as Second Life to simulate the stresses in a therapeutic context. Studies have shown that such simulations can lead to a clinically significant lessening of PTSD symptoms. Some researchers are even using simulations to identify potential PTSD sufferers —and deal with their problems — even before the warfighters are sent into combat.

Therapists only wish that vets would take greater advantage of the treatment tools at hand.

"Far too many of our warriors come home and, despite difficulties they are having, are not going to come and see a psychologist, a social worker, a psychiatrist," clinical psychologist Greg Reger said this week in a news release announcing the establishment of the Pentagon's virtual world for vets.

The world was created in Second Life by the National Center for Telehealth and Technology, also known as T2. Reger, who is acting chief of the center's innovative technology applications division, said the T2 Virtual PTSD Experience can help tech-savvy warfighters and their families learn more about PTSD in the comfort of their own homes.

Second Life gives users the opportunity to create virtual-reality avatars, and then send those avatars walking (or flying) through computer-graphic environments that are similar to real-world locales. On T2's turf, for example, avatars can visit a welcome center anonymously and learn more about the psychological difficulties associated with combat deployment.

T2Health.org

A virtual experience on an Afghan street helps vets and loved ones understand the causes of post-traumatic stress disorder.

"The cornerstone of the experience is when they leave that area and go into an area that teaches about the causes of post-traumatic stress disorcer," Reger said. "They enter a space where they get into a Humvee and are taken through a computer-generated simulation that includes [intense fighting on an Afghan street and] an explosion."

While this is happening, the virtual visitors receive audio instruction that puts the stressful experiences in perspective. There's even a simulation that's set in a Stateside shopping mall — because many PTSD sufferers say they feel heightened anxiety when they're in a mall or other public gathering place.

The T2 experience isn't just about stress, however. The virtual environment also offers relaxation zones, guided meditations and forums where real-life vets can talk about their experiences using the computer-generated interface. "Second Life provides the opportunity to interact with anyone who is in that space," Reger said. "Any warrior who goes in there will be able to talk with whoever is in that space."

T2Health.org

A Second Life simulation shows a relaxation exercise in progress at a virtual resort.

The center's aim isn't to keep stressed-out vets bottled up in cyberspace. Rather, the goal is to provide an virtual avenue that leads to a healthier life in the real world. "We created an environment that lets people learn by doing, rather than reading text and watching videos on two-dimensional websites," said Kevin Holloway, the psychologist who led T2's virtual-world develoment. "They can learn something new each time they visit."

Click on the links below to learn more about T2:

• A Web guide to the T2 Virtual PTSD Experience
• SLurl link to T2 PTSD Education in Second Life
• News Tribune: Virtual world helps soldiers explore PTSD
• KOMO News: Virtual world helps soldiers battling PTSD

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To be 30 years younger is the wish of many an aging soul. For actor Jeff Bridges, movie magic makes the dream a reality in "Tron: Legacy," the sequel to the 1982 sci-fi blockbuster, in which the actor plays his younger self in a digital universe with his long-lost son.

The feat is the result of new technology that allowed filmmakers to record the actor's facial movements and superimpose them onto a digital model of Bridges' younger self.

"He's the first actor in cinematic history to play opposite a younger version of himself," the movie's visual-effects supervisor, Eric Barba, said in a Daily Mail profile of the 60-year-old actor.

In the original movie, Bridges played video game hacker Kevin Flynn, who got sucked into a computer and was forced into playing gladiatorial games. In the $300 million sequel, which opens Dec. 17, Flynn's son enters the "Tron" virtual universe -- where he encounters a youthful version of his dad captured in the digital body of Clu 2, one of his creations. The Daily Mail explains the tech behind Clu2:

"Bridges' face was scanned in three dimensions and a 3D model produced, marked with 52 points on the cheeks, eyes, forehead and mouth –- everything that moves when we express an emotion. This digital version of the actor's face was then 'de-aged,' based on footage of the young Bridges from 1984's 'Against All Odds.'"

Disney

Computer technology allows actor Jeff Bridges, shown here, to appear nearly 30 years younger than himself in the new movie Tron: Legacy, opening December 17.

While acting as Clu 2, Bridges had his own face marked with dots in the same 52 places and wore a tiny head-mounted camera that tracked their motion. The facial expressions of the real Bridges were then mapped onto the digital Bridges.

Ohio State University computer scientist Rick Parent predicted the ability of movie technology to turn back time on an actor in a 2002 msnbc.com interview -- which was sparked by Andy Serkis' virtual performance as Gollum in the "Lord of the Rings" movies. 

The new "Tron" movie, he told me, shows that the technological goal of replacing real actors with virtual actors has been reached ... "to a degree."

"With a movie like 'Tron,' the whole premise of that lends itself to computer graphics because it's inside a computer, and therefore the audience has some tolerance for not exactly a real person," he said. But there's a difference between that kind of movie and using a virtual or synthetic replacement "for an actor in a real live scene," he added.

That type of technology still requires advances in motion control, as well as the ability to portray realistic effects such as light reflecting off skin and hair. Faster computers and bigger studio budgets are bringing the technology closer and closer, Parent said, "but there's still a ways to go."

If digital technology continues on its current course, Bridges said the day may come when he could appear in movies without actually acting. "I could still make films," he told the Daily Mail. "I can say, 'I'll lease you my image.'"

Maybe. But Parent said Bridges would still need to do the motion capture work -– the recording of facial and body movements for mapping onto his synthetic likeness. For better or worse, the technology is nowhere near completely replacing real live actors.

"With removing the actor completely, now you've got a whole different problem of building those body motions, those facial motions, the speech -– which is a whole other problem. Building that essentially from scratch … that's a whole other level of complexity, and we are not there at all," Parent said.

John Roach is a contributing writer for msnbc.com. Connect with the Cosmic Log community by hitting the "like" button on the Cosmic Log Facebook page or following msnbc.com's science editor, Alan Boyle, on Twitter (@b0yle).