Issue: Volume: 23 Issue: 9 (September 2000)

In Sync




By Katherine Tyrka

SIMULATION

Synchronized swimming is a complicated yet elegant sport that focuses as much on athletics as ballet, with eight swimmers moving in precision as they create forms to music. Synchronized swim teams typically spend a full year creating their water routines and perfecting the execution of their moves by working them out on paper or with the entire team present. However, through the use of real-time simulation technology, the French National Synchronized Swim Team-currently ranked fifth in the world -has found an easier, more effective method for expanding its routines and optimizing its members' practices.

The French team recently began using the new human-modeling "swimmers" software, a variation of Syseca's (Malakoff, France) U-Man program, originally designed to analyze ergonomics in industry. The adapted program incorporates all the features of the original U-Man mannequin, which can perform a combination of movements while integrating various constraints. For the swim application, the developers adjusted the software to reflect the gravity change that occurs when the swimmers are in the water, and the increased flexibility of the athletes.

Called U-Man Swimmer by its users, the program was adopted several months ago by the French swimmers. However, because of the lengthy time involved in creating and perfecting its routine, it was too late for the team to use the software to help during its run for the gold medal at this month's Summer 2000 Olympics in Sydney, Australia.
The French synchronized swim team is using an adapted version of the U-Man simulation program to create its routines. As a result, the group spends less idle time in the water, and the members are now able to practice new maneuvers on their own.




To develop the U-Man Swimmer's application, Syseca used special kinematics algorithms that the company designed specifically for simulating swimming, along with positions of the human body in the pool, trajectories of the bodies as they dive into the water, and constraints on the human body. "Working with the swim coach, we modified the constraints and adjusted the parameters, since swimmers are more supple that the average person riding in a car, for example," says Pierre Bouchon, director of Syseca's Real Time 3D Graphics and Virtual Reality Department.

Currently, the French team's coach, Anne Capron, is working with Jean-Michel Collet, who composes the routine's music and is familiar with the software, to develop new routines for the swim team. First, each swimmer mannequin is given a trajectory for a dive, with positions at certain points in the software's 3D model of the pool. The program then automatically transitions the mannequin from one position to another.

"[Capron] imagines what she wants, and I implement it," says Collet. "We can define arm and leg rotation with the mannequins, and even where the mannequin should look. This new method of working will take us much further in the development of the trajectories, movements, transitions, and gestures used by the swimmers."

In fact, the coach can create the majority of the team's routine using the U-Man Swimmers application, viewing the choreography with and without the water, and making as many modifications as needed. According to Capron, she did not have to adapt her methods of creating routines just because she was using the software, since the program was adapted to her work processes rather than vice versa. "We can now explore many more possibilities, because creating the choreography is no longer dependent on having the whole team present," she says.

Using the program also enables Capron to work with the music from the beginning and immediately view the larger forms of a routine. Using the "vicarious experience" module from the original U-Man application, the coach can view the routine through the judges' eyes or through the eyes of each swimmer. "Until now, we had to put the swimmers in the water and let them try things out, with varying results," says Collet. "The process is faster using the application and easier on the team members, who no longer have to spend so many hours in the water while parts of the routine are worked out. We can develop routines earlier and give team members more time to work on their gestures both individually and as a group."

With the team spread throughout the country, the application will also be used as a communication tool during the preparation for future Olympic qualifying rounds. The coach can record different points of view for each swimmer and send routines on CD or video so members can see exactly what they have to do and can train on their own. "It's like being able to send a theater actor a script to learn before going into rehearsal for a performance," says Bouchon.
Each U-Man Swimmers mannequin can be modeled using 1000, 4000, or 12,000 polygons, depending on the level of detail required and the computing power available. The software uses inverse kinematics to calculate the body movement, and adds real-time free-fo




The first version of the software is now being used to explore possible routines and to create a library of the 150 classic positions, similar to the standard positions developed in ballet. Once the base library is completed, the coach will be able to draw on these to speed the creation of new routines for the team. As new positions are developed, the library will be updated accordingly.

The application currently runs on a dual-processor Hewlett-Packard Kayak with an Fx6 graphics board, running Windows NT 4.0. The routines can also be brought poolside, using a laptop and QuickTime videos.

A second version of the software, due out in late summer-early fall, will include a copy/paste function to add identical movements to the mannequins when needed. All the movement is shown in real-time, and the timing can be adjusted to coordinate the swimmers' movements with the music. An interface between the music and modeling applications is also being developed for this later version.

Development of the U-Man Swimmers application is part of an overall project by the French Sports Ministry to incorporate technology into the country's sporting programs. In fact, Syseca has already collaborated with the Ministry on real-time simulation of the America's Cup and other races.

Only time will tell whether adoption of the technology will help the French synchronized swim team improve its world ranking. But it's one technological plunge the group is willing to take.

Katherine Tyrka is a freelance writer based at the GEID Press Agency in Paris. She can be reached at ktyrka@compuserve.com.

U-Man, Syseca (www.syseca.thomson-csf.com/simulation)
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