Ronald DeBrabant decided to use GM's cutting-edge 3-D virtual-reality technology to entertain 370 children visiting the automaker on its most recent "Take Your Child To Work" day. He had designers create a pterodactyl cartoon character that pokes its beak directly into the faces of the kids sitting in the room and wearing specially designed headsets. The image proved to be a bit too true-to-life: One little girl screamed and started crying.

DeBrabant runs GM's Envisioning Center, a three-screened, theaterlike room where engineers view three-dimensional images of model-car designs. They can view the images from any angle, and at such exact scale that they can walk up to the screen and use rulers to measure the width and height of any detail. The sheen of paint or texture of a dashboard is nearly indistinguishable from that of an actual car. Designers can change a car's color at the click of a mouse. They can even reconfigure the way lighting and background affects a model. The center can project a vehicle driving on a country road, with the trees and buildings of that setting reflected in the paint and contours of the virtual car.

The center allows for meticulous inspection of design detail. For example, a designer can manipulate the image of the car until it almost seems that he or she can reach into the interior and manipulate the steering wheel. "Designers can study how much headroom a driver has, how ergonomic the dashboard controls are, and make absolutely sure that every aspect of the vehicle is perfect," DeBrabant says.

Engineering teams on different continents frequently interact in virtual reality using the center's collaboration capability and can manipulate the 3-D models as easily as their U.S. counterparts. In later design stages, the virtual-reality center is used to display models detailed enough for market testing and for execs to decide which ones to manufacture. Last fall, Robert Lutz, vice chairman of product development, used the center to pick concept cars for this year's Detroit auto show. His top pick, Solaris, went from a CAD model to a concept car in four months, eliminating the physical-prototype process. Lutz drove the new model onstage at the show.