Motion-capture technology arrives at the Aesthetic Technologies Lab, inspiring cross-disciplinary research and a chance for the School of Dance to go digital.
Feb. 22, 2006
By Anita Martin
Dance diva Martha Graham once stated that, "the only record of a dancer's instrument is his body, bounded by birth and death." As a former Ohio University dance student, I quite agreed.
That is, until I plugged my rusty "dancer's instrument" into the university's newly acquired motion-capture suit to see a digitized image mimic my every move across a live screen.
Ohio University's Aesthetic Technologies lab (@Lab for short), records dance and other movement using motion capture, a technology famously applied in such animated films as "The Lord of the Rings" and "The Polar Express." The suit, a product of Measurand, Incorporated called "ShapeWrap II ™", is the lab's newest resource for cross-disciplinary collaboration and fine arts innovation.
"We've been getting calls from everyone from the College of Osteopathic Medicine to athletics to engineering to sports medicine," @Lab Director Katherine Milton says. "The suit has generated enormous interest among different disciplines."
In addition to its research potential, ShapeWrap II works with 3-D imaging software such as Maya, which the @Lab also offers, to create digital animation. Meanwhile, faculty and students in the School of Dance consider the performance possibilities of live and recorded motion capture.
Motion capture on the go
Measurand Inc. Vice President Scott Thomson bills ShapeWrap as the most portable and affordable of available motion capture-systems. In fact, the @Lab now boasts the only field-certified portable motion capture system in Ohio.
"For the real top-of-the-line equipment, you would need a closed-in system, which means these lights would have to go," Thomson says. He points to the ceiling of the @Lab's experimental dance studio, on the second floor of Putnam Hall, "And the building would have to be reinforced to prevent shaking from the dance classes.... Whereas [ShapeWrap] can be used anywhere you can take a laptop computer, under many conditions."
That "top-of-the-line" equipment Thomson described employs optical technology, used in "The Lord of the Rings" for Gollum's character. The optical system costs about ten times more than ShapeWrap, not counting the major renovations that would have been required to build a "closed-in system" in Putnam Hall.
"This is our way to begin building a vocabulary for this technology," Milton says. "Motion-capture animators and motion-capture technicians will be in demand."
Connecting the dots
The morning after ShapeWrap II arrives on campus, Thomson and his assistant trainer, John Saad, lower a black elastic breastplate over my torso, fastening the flexible armor with Velcro. Soon, long strips of fiber-optic ShapeTape snake from my shoulders to my hands and feet, fastened at points around biceps, thighs and calves and crisscrossing my waist like an artillery belt. The ShapeHand glove links my wrists to each fingertip and weight sensors strap to the bottom of my feet. I feel like a minimalist Power Ranger, ready to morph.
"This is what I call a full-meal deal," Saad says, as he secures my battery pack to the Velcro on my upper chest. "You've got full-body motion capture all the way to your fingers."
Next, Thomson sits at his laptop to process the live data from my wireless suit through his ShapeRecorder program. Upon a large screen, he projects a humanoid arrangement of geometric shapes standing on a grid plane. As I nod, the inverted cone-head bobs atop a quadratic torso. The arms and legs are long, jointed tubes, all supported by a rod-like spine.
This image lends visual substance to the point data taken from my orientation sensors. The digital artist can transfer the point data to animation software such as Motion Builder and Maya and connect the points to a digital model, say an animated ninja or a traditional African dancer, causing the character to move as I do.
"We call that 'rigging' the model," says Nathaniel Berger, @Lab project manager. "Once I've rigged a computer model, the model will always move with those points."
From space shuttle to dance floor
Measurand, based in New Brunswick, Canada, incorporated in 1993 when founder-President Lee Danisch patented an innovative fiber-optic sensor. Measurand commercialized 3-D flexible arrays of sensors, which measure shape according to positions along a curve or across a volume. By the late nineties, they were working with the Canadian Space Agency to develop ShapeTape.
One of Measurand's first customers was NASA, who used the technology to analyze body movement within a spacesuit. These days, the ShapeWrap II is a popular educational device, teaching art students the skills of motion-capture animation.
"This is the first time we've trained dancers to use the equipment," Thomson says. "It will be interesting to see how they use it."
As soon as I'm suited up and calibrated, I know how dancers will use it. Beginning with my arms and legs, I begin snaking and swaying, rocking and roll—
"Don't do that," Saad says, but it's too late. I've rolled to the floor and lifted my legs into the air. Saad pulls me to my feet and requests that I keep at least one foot planted on the ground, to keep my digital double "gravity-oriented" in space, and to avoid suit shifting.
Marina Walchli, associate professor of dance, doesn't seem too worried about these limitations. "What happens when you lift both legs is that the screen image falls through the grid, which looks kind of neat," Walchli says. "We can work with that."
At the School of Dance, ShapeWrap II has also caught the attention of Zelma Badu-Younge, assistant professor of dance, who hopes to incorporate the suit into future concert choreography.
"More time is needed for everyone to figure out the ShapeWrap system properly," Badu-Younge says. "I do plan on using it in the near future. I find it very exciting."
Across the university, motion-capture research initiatives remain in the brainstorming stage, but ideas keep trickling in, including testing in zero-gravity environments and kinesthetics studies. Meanwhile, the @Lab team takes the time to get better acquainted with its new technology.
"We're going to experiment with the system in the lab—see what happens when we reverse the arms, or wrap the tape a different way," Milton says, "I expect we'll be pushing the limitations of the technology."
Anita Martin is a writer with University Communications and Marketing.