"They seem to fulfill little girls' wishes to be elegant and graceful," said Rob Hudnut, a vice president of Mattel Entertainment, a division of the toy maker.

So small wonder that two years ago, when the company decided Barbie was ready to make her video debut, the vehicle they chose was "The Nutcracker," with Barbie playing Clara in an animated adaptation of the E. T. A. Hoffmann ballet classic. The video and DVD have sold 3.5 million copies.

Now for her followup, she has been cast as Odette in "Swan Lake," among the plummiest roles in ballet, one that most dancers have to wait years for a chance at. The video and DVD of "Barbie in Swan Lake" will be released by Artisan Home Entertainment on Tuesday.

For the choreography, Mr. Hudnut, who was the executive producer for the films, enlisted Peter Martins, ballet master in chief of the New York City Ballet. "I couldn't resist the opportunity," Mr. Martins said. "My 7-year-old daughter, Talicia, is a Barbie fan and these films have the potential of reaching millions of young girls. It will probably be the first time they see ballet, and it will be performed realistically."

To make the dances true to Mr. Martins's choreography, the producers used a technique called advanced motion capture imaging. It was developed nearly 15 years ago for medical applications. The technique, also known as biomechanics, enables doctors to analyze how a person walks, to diagnose problems and to prescribe corrective measures. In the early 1990's, animators realized that it could be used to replicate human movements and adapted it to computer games. At first, it produced movements that were often jerky and jumpy.

Such flaws earned the technique a bad reputation among animators, most of whom used keyframe animation, a computer-assisted method in which characters are drawn by hand. "Purists saw it as a cheap and nasty alternative to keyframe animation," said Owen Hurley, who directed the Barbie films.

Yet improvements in filtering and clean-up techniques made it possible to overcome most such defects. As a result, when viewers see Barbie, as Odette, dance with Prince Daniel, a k a Ken, the dancers' movements will be computer-generated replications of those of the City Ballet principals Maria Kowroski and Charles Askegard. Other City Ballet dancers served as models as well: Ellen Bar for the Fairy Queen; Benjamin Millepied for Ivan the Porcupine; Abi Stafford for the Fox and Janie Taylor for Carlita the Skunk. (Merce Cunningham and Bill T. Jones have also used motion capture technology in films of their works.)

The dancers spent two grueling, six-hour days at City Ballet's studios in Lincoln Center last year creating the dance sequences for the new film. Working with a crew of 11, Mr. Hurley arranged 16 cameras around the area where the dancers would perform, according to the publicity trailer for the film. The cameras, called light-emitting cameras, send out a beam of light that bounces off a reflective surface and returns to the camera. They tracked the movements of the dancers, who wore Lyrca body suits with reflective spheres attached by Velcro to their elbows, wrists and legs. Each one wore a distinctive array of markers, so the cameras could tell them apart.

"Whenever possible," said Mr. Hurley, who has won awards for episodes of the animated television series "Reboot," "Beast Wars," "Shadow Raiders" and "Weird-Ohs," "we shot the dances with multiple characters separately, so the data we collected would be less confusing. We learned in the process that we needed more reflectors on their feet and hands to get better articulation."

After filtering and refining the data at the headquarters of Mainframe Entertainment, one of the producers, in Vancouver, British Columbia, the production team took that information and superimposed it on computer models of the characters. "I try to complement the dance as much as possible," he said, "and involve the camera in the choreography, without getting in its way."

Once the scenes were roughed out, animators provided the characters' faces with emotional expression. After all, viewers want to see Barbie swoon over the handsome prince and worry about the evil wizard Rothbart.

Ms. Kowroski and the other dancers enjoyed their transformation into digital dancers. "We were excited about learning a new technical process," she said. "We could see the results on the computers right away."

She found the Lycra suits comfortable, but the reflectors were occasionally problematic: "Sometimes when I was dancing very fast, they'd fly off, and then we'd have to stop and start all over again." She also had to learn to play the roles of both the white and black swans within one sequence, an abrupt character change that differs from most versions of the ballet. But she felt quite at home in her role. "I had a ballerina Barbie when I was a little girl," she said.

Source: NY Times