The Dancing Grids

The grid patterns on the large video screens behind the performers originated in Fred Bookstein's researches in morphometrics, the measurement of biological shape and shape change. They act as a simplified representation of each dance, translated into a different medium. The grids began as diagrams of changing features of the human brain. Designed by Bill Green at the Institute of Gerontology, the Edgewarp computer mapping program places landmark points of human brains onto a grid to depict and measure differences between normal and abnormal groups. For example, the difference between the brains of healthy children and the brains of children affected by fetal alcohol syndrome warps the grid to produce a visual image of the consistent effect of the syndrome. This difference appears to us as dynamic change in a three-dimensional surface. Bookstein's research shows that we can understand shape differences between brains better this way than we were to compare tables of average measurements. His graphical method has considerable promise in studies of craniofacial surgery, normal and abnormal growth, and the development of brain diseases such as Alzheimer's.

Bookstein had been asked by Cogswell to contribute some of his brain images to the Enigmas Project, as they emphasized the themes of human exploration in both inner and outer space. As the project developed, the contributors realized that they could use the grids of the Edgewarp program to complement the dances not only conceptually but also geometrically -- like differing brains, they represent deformations and changes of biological forms. With the assistance of Bill Green, the contributors adapted the Edgewarp technology to the dances. First, Sparling compacted the choreography of his solos into their essential movements, distilling about forty minutes of dance into a dive-minute series of motions. In order to create a "normal," neutral position from which to map the changes in his body caused by the dances, the collaborators used the pose of Leonardo Da Vinci's famous "Vitruvian Man," a male body with arms and legs stretched outwards, the whole spread into a flat plane. Pieces of reflective tape marked twenty-one key landmarks of Peter's body (forehead, shoulder, elbows, wrists, hips, and so on), and a square grid was tacked to this figure with corners near the original hands and feet. Beginning with the Vitruvian pose, Sparling then performed the key gestures of the Enigmas in front of Bob Andersen's video camera. At every sixtieth frame of the videotape, Cogswell relocated the landmarks on the image of Sparling's body position. These new landmarks deformed the original grid, following the pattern of the dance. Using conventional animation techniques, Bookstein finally turned the sequence of deformations of the grid into the smooth motion that was seen on the screen.

Although these grids, like the video images on which they were originally mapped, are two-dimensional, we cannot help but perceive the shape changes as three-dimensional. Our eyes "read" the shifting two-dimensional grid as changes in a three-dimensional form that began as the frontal plane of Peter Sparling's figure. These grids enhance our awareness of the changes in the three-dimensional space immediately around the dancers. In the end, each dancer moves alongside a beautifully simplified representation of his or her dance, translated into a different medium. In Yeats's phrase, we now "tell the dancer from the dance."

History of the Project
The Hubble Spacecraft Telescope Images
Introduction
Enter the Exhibit