Speaking in their own language about lines, curves, forms and brand character, the designers run their pointers over all the facets of a life-size red sports car that spins slowly in space on the giant screen, as if suspended by a magician's trick.

So far, this car exists only in the designers' imaginations and in the billions of 1s and 0s that define it in digital code. The team agrees on a few minor tweaks to the design, and sets a meeting to look over the changes the following day.

It's just another design meeting in the age of computer-assisted automobile design - with one important distinction: the GM team that just met spans six time zones.

Thanks to a blend of computer-aided design, virtual reality animation and Internet-age connectivity, GM designers and engineers are blazing new trails in the increasingly global automotive industry by holding virtual design meetings where participants throughout the world "meet" around a computerized model of a car and discuss what they're seeing.

GM is establishing 19 virtual reality design studios on four continents to link these collaborative sessions. Although oceans and time zones may separate them, designers and engineers collaborate as if they were sitting next to each other.

"It is amazing to watch," said Don Siefkes, manager of the Virtual Reality (VR) Studio in the General Motors Design Center in Warren. "We flick a key here to rotate the model and they see the same thing in Germany. It just blows you away."

The custom software that enables these virtual meetings is called VisualEyes. Now in version 4.0, VisualEyes allows the company's designers and engineers to work faster and make better decisions. "It allows you to look at seven or eight iterations, where you used to do only one," Siefkes said.

While a huge Internet pipeline relays the digital information comprising the model vehicle to multiple sites, speakerphones convey the conversation. The GM researchers who developed and wrote VisualEyes call it "building cars out of light."

Each GM VR studio features wall-sized projection screens so cars can be viewed in full-size (100 percent scale). With the help of special glasses, designs may also be viewed in 3-D.

In the design process, an early model is limited to a vehicle exterior or a simplified interior. But as the development process moves forward, the model grows to include all the detailed parts, right down to nuts and washers if one looks closely enough.

"They need a full-size model to use their intuitive sense of depth and curvature, " said Larry Peruski of GM's Vehicle Analysis and Dynamics Lab, a member of the team that has worked on developing VisualEyes for five years. "If you put a 6-inch cube up there, you ought to be able to walk right up to it and make sure it's 6 inches." The designers have been known to place their chairs alongside the VisualEyes projection of a car to get a rough sense of the fit of seating.

To aid these design discussions, the VisualEyes team found that head-mounted displays typically associated with virtual reality aren't practical for business meetings or viewing life-size objects. Instead, they use enormous rear-projection screens driven by Silicon Graphics, Inc., Onyx computers, considered the gold standard in visualization.

Several VisualEyes studios also include CAVE (Cave Automatic Virtual Environment), a special box-like projection system that surrounds the viewer with a 3-D image on three walls. CAVE projection is especially useful for modeling interior features, which is the most intensive modeling function of the design process. Again, creating interiors out of light rather than clay and wood allows more design options to be reviewed faster and at less expense.

For long-distance collaboration on an interior, the VisualEyes team has also developed "avatars' -- 3-D models of people to represent participants virtually. Viewed in a U.S. studio, a participant in Germany is represented by a simplified human figure which has a still image of his or her face superimposed on the front of the avatar's head. Tracking devices on each participant's head and hands make the avatar move as the real person does. As the collaborators explore a car interior, each avatar is in its respective seat and other participants around the globe view a person's activities based on the movements of his virtual counterpart.

But the avatars are a little creepy right now. "The feeling is that for highly orchestrated meetings, the avatars get in the way, and people don't want them," said Randy Smith, another member of the VisualEyes team. "They can block a view, or you can end up inside each other looking out. There are lots of personal space issues that aren't resolved because the controls are still pretty primitive."

Most users are quite happy with the pointer, a sort of virtual light saber that responds to the motions and clicks of a hand-held device, much like a 3-D mouse.

The Future

GM is passing on VisualEyes technology to an outside contractor, Engineering Animation Inc. EAI, which will become the supplier of the software, called Visconcept. "Visconcept is an enhanced 3-D visualization system developed in close collaboration between General Motors and EAI," said Diane Jurgens, director of global CAD/CAM and visualization at GM. "EAI has successfully taken the best parts of GM's internally developed

virtual reality capabilities and re-engineered them in a way that makes it possible for us to deploy a powerful immersive virtual reality tool across the GM organization." GM's Virtual Reality Design studios are located in Russelsheim, Germany; Sao Paulo Brazil; Warren, Pontiac and Troy, Mich.

Though they haven't quite decided what to do for an encore, VisualEyes team members are proud of what they've accomplished. "This was unexplored territory. There wasn't any template for it," Peruski said.

Virtual Collaboration Projects Using VisualEyes

Virtual Crash-Testing

Modelers can watch individual, color-coded components of the car react to a crash over and over, freezing frames, spinning around the model, and even getting inside to view it from the driver's seat. In one early test, an engineer literally stuck his head through the hood of a wrecked virtual car to see what happened inside the engine compartment. To accomplish realistic crash modeling, Computer Aided Engineering (CAE) software is linked to VisualEyes. That software not only has to include the shape and size of all the parts, but how they are attached to one another, the physical properties of each different material and most importantly capture the physics associated with the crash event so that components bend and break realistically. Considerable progress has been made in the development of these methods to enable engineers to take a quick, low-cost glance at what a design change might mean to crashworthiness without actually wrecking a car, Peruski said.

Virtual Wind Tunnel

Similarly, other CAE software, linked to VisualEyes, allows aerodynamic characteristics to be measured and modeled with quick feedback. A virtual stream of smoke flows over the car body, just as it would in a real wind tunnel test, and engineers see how a design change will affect the flow. Reduced testing of full size clay models means faster, less costly design.

GM designers have been viewing full-size clay models outdoors on the "design patio" at the GM Technical Center in Warren for more than 40 years. The plaza area is paved with hexagonal bricks and ringed with trees, and the car can be rotated on a turntable to be viewed from all angles. Today, the VisualEyes software can do the same viewing in the same setting, but one better. Multiple cars can be viewed at once, with realistic reflections of the sky, trees and bricks in its paint and glass areas. The Design Center recently viewed 21 trucks simultaneously on the virtual patio.

The software also enables designers to superimpose one vehicle over another to see where their dimensions differ and by how much. "And besides, there's never a rainout," Smith added.

Interior Design

Rather than wood and clay mockups of all the louvers, dials and buttons of a car interior, a virtual 3-D model allows several designers to view everything at the same time. One designer wears a special set of goggles that tells the computer where he is looking, and the software turns the model accordingly to appear realistic. Designers can change color schemes, instrumentation and ergonomics on the fly.

Workcell Modeling

VisualEyes has also been used to measure a worker's position on the assembly line and how he or she would interact with a new piece of equipment or a new car part. "One modeling exercise was to see how a worker would lift a piece of sheet metal and put it in position," said VisualEyes co-author Don McMillan.

"Unfortunately, there wasn't any way to replicate the weight of the part for the worker to experience in virtual reality, but that may come someday," McMillan said.

Formability

GM's stamping engineers use VisualEyes to analyze the design of GM's sheet metal parts for strains and stresses. Using CAE software, math models of the stamping die surfaces are constructed and simulations of the forming of the parts are analyzed before physical models or prototypes are developed.

(August 28, 2000)