James Braham
Senior Editor
Behind the wheel in an Indy-car race, I was roaring through hairpin turns, coming inches from concrete walls, passing other cars through the narrowest of openings, and accelerating down straightaways. Actually, the gloved hands on the wheel belonged to racing champion Mario Andretti, who was pulling out all the stops, even speeding through a downpour on a slick track.
Suddenly I felt my tires lose traction, and I spun out, full circle, twice around. But not to worry. Almost instantly I was back on track, soon exceeding 200 mph, without even a helmet for protection.
After that race-car experience, I was off on a mad, mad roller-coaster ride through “Elvira’s Tragic Kingdom.” Up and up we climbed, into the rafters of a magnificent cathedral, and then — hold on!— we were plunging down a long, perilously steep descent, crashing through a stained glass window, and careening through graveyards, dungeons, and dark forests.
A hair-raising race against another sports car followed that. We were much too close for comfort as we sped along freeways and up and down bridges, busted through barricades, and even hurtled into space, landing back on the road with a thud. I exited exhausted, but again without as much as a scratch.
It was a similar scenario when flying a jet fighter. Now, however, I wasn’t just along for the ride. I was at the controls. Me, a neophyte, alone in the cockpit, doing loops, flips, and corkscrews, oblivious to the laws of gravity, and somehow managing to return safely to earth.
No-risk thrills
Welcome to the expanding world of simulated recreation and entertainment — rides, cars, and capsules in which you can experience the thrills of the real thing without any of the risks. Here all the spinouts, crackups, and other disasters exist only on screen.
On all these attractions, which I enjoyed (gulp!) at the annual trade show of the International Assn. of Amusement Parks and Attractions in the Orlando Convention Center, I felt as though I really were racing with Mario, riding a coaster, or piloting a plane. They were all moving experiences, but in reality only the platforms below the seats moved. And sometimes they moved in all six degrees of freedom (DOF). They rolled, pitched, yawed, heaved (up/down), surged (forward/ back), and swayed (left/right) — and so did I. The seat actually moved less than a foot in most of these experiences. (Enclosed ride capsules, such as flight simulators, can rotate up to a full 360°).
All this technology is a result of the Hollywood film studios which produce such realistic and vivid video hooking up with the mechanical engineering-oriented companies which supply the motion-base actuators and controls. It’s also a spin-off of military flight-simulation companies venturing into entertainment.
How it works
When the computer-generated video, or actual film, and motion are perfectly synchronized, they fool our senses to make us think and feel we’re experiencing the real thing. “The most important thing in ride simulation is the programming. The motion base and screen movement must be coordinated,” says John Kostyal, market sales manager for Vickers Inc., whose new, quiet, integrated motor pump supplies the hydraulic power to make the cylinders bounce rapidly up and down, in countless combinations, below some of these motion bases. “This (coordination) is even more important than the number of degrees of freedom of motion. Your mind is not sold if it’s not coordinated,” he stresses.
Iwerks Entertainment in Burbank, Calif., developed the “Super Speedway” race with Andretti and the “Elvira” ride with its new TurboRide technology, which combines motion simulators with large format film-making. The film comes first; the motion base is then programmed to respond to it. For the Speedway ride, for example, 17 hr of Indy-car racing film, shot for a documentary, were edited into 3 min, 50 sec of nonstop thrills. One reason it’s so realistic is that the man operating the camera, at over 200 mph, was Mario Andretti.
Mario’s son Michael also drove in the film, and Iwerks had him purposely wipe out three times in a row. It then took the highlights and combined them to create the impression he spun around twice in succession. After the film was cut, motion-base programmer Paul Pieper accentuated every twist and turn to the hilt. “It was fun, but difficult, because it’s different than your normal rail ride or flying car,” he explains. “You have to simulate the feeling that you’re on the ground on a two-dimensional plane and you’re feeling high g forces as you’re going into turns.”
When the inside tires go over the speed bumps on a turn, the programmers created “vibrations that cause the chair to chatter a little, like you’re actually running over road debris,” says Pieper. The ride even includes a pit stop in which “we let the audience feel the lug wrenches at work,” he adds.
Top speed in a simulation ride is typically 60 to 80 mph, but “Super Speedway” hit over 200 mph. “And since it’s printed on large-format film, we can show it on screens up to 60 by 80-feet. You can even see the details of a tree way off in the distance as it whips by. It’s a total sensory experience,” Pieper exclaims. Iwerks platforms for motion simulation range from two to 40 seats, while its hydraulic bases come with three DOF — heave, pitch, roll — up to all six axes.
All this motion-base technology springs from the original Link flight simulator, which companies are now adapting for the entertainment industry. McFadden Systems Inc., for example, a leading producer of flight-simulation equipment, has its own entertainment division, which has developed a 12-person capsule simulator and a 15-seat motion platform with six DOF. The Santa Fe Springs, Calif., company recently installed motion simulators totaling over $7 million for three major attractions in Las Vegas. Its simulation objective is simple. “We look for changes in velocity and direction, and then we replicate that acceleration in the motion base, so you feel what you see,” explains Michael Rogers, director of sales and marketing.
Interactive racing
In its race-car installation at the Sahara Hotel/Casino, McFadden was a subcontractor for Illusion Inc., which is doing some of the most innovative simulation work. Illusion, which developed the Simnet simulators that trained U.S. soldiers for Operation Desert Storm, has become a leading supplier of networked, interactive, virtual-reality technology for the entertainment industry. At its “Sahara Speedworld” Indy-car racing center, as many as 24 highly detailed Indy-car simulators compete in the same virtual race, using the company’s SpeedSports technology. It’s the most technologically advanced VR simulation anywhere, the Westlake Village, Calif., firm claims.
“It’s a very accurate, interactive recreation of a race-car ride, built with the same technology used to build flight simulators that would qualify for F.A.A. certification,” says Bob Jacobs, the engineer, mathematician, and psychologist who’s company president. Each car is a 3⁄4-scale racer with a poly-resin body mounted on a tubular-steel frame, and all the usual controls. Each sits on a high-performance motion base offering six DOF, in front of its own 133°, panoramic, 20-ft-diameter screen, displaying real-time, computer-generated imagery.
Following a brief video training session with Indy champion Danny Sullivan, drivers select their course — a virtual replica of either the 1.5-mile Las Vegas Motor Speedway or a road course through the streets of Las Vegas. They also choose a 350-hp “Indy Lite” or 760-hp “Indy Pro” car, with manual or automatic transmission. The system, which does not involve headsets, simulates g-force motion cues experienced in real racing, and includes road feel, interaction with other cars, and collisions.
A 160-parameter dynamic model accurately simulates every aspect of real Indy-car performance, including engine horsepower, transmission torque, braking response, tire pressure, suspension, and aerodynamic wing angles. The force feedback and vibration devices in the steering wheel and seat provide immediate, realistic response to the slightest movement of the steering wheel or pressure on brake or accelerator. Track surface, wheel traction, and engine and vehicle vibration are all considered.
A spatialized, phased-array sound system with 16-channel, multiple-speaker immersive technology envelops the drivers, reproducing the roar of the engine, the whoosh of passing and being passed, the clatter of tires going over different surfaces, and the screech and bang of collisions and crashes. Drivers even feel some wind in their face, varying with car speed. And throughout the race, each driver receives guidance from his or her own pit crew. If fuel is running low, for example, he will be instructed to pull into the pit for a quick fill-up.
Like Iwerks and McFadden, Illusion develops ride films, too, even 3D ones for motion-base simulation, but Jacobs maintains these passive experiences cannot match an interactive one. “Ride films put you on a motion system that moves in relation to what happens in a captured scene or movie. You just go along and enjoy it. With our attraction, you create the action, so every time you ride it’s different. No matter how good the film and motion programming is for a ride film, it’s still a passive experience. It’s totally different when you are in control.
“People forget they’re in a simulator within the first 10 seconds of a race,” Jacobs continues. It’s so realistic that drivers often perspire heavily, their arms get very tired, and after the race (which typically lasts 6 to 8 minutes) first-timers invariably ask how fast they were going, even though their instruments displayed all that information. “The reason they ask is they couldn’t take a half-second to look away from the track to the speedometer. It’s that intense,” Jacobs notes.
Race driver Emerson Fittipaldi is so impressed with all this simulation that he calls it the closest thing to actual racing he ever experienced, “except for one very important distinction, crashing doesn’t hurt.”
Psychology and math
Illusion uses hydraulic actuators made by the Dutch company Hydraudyne for its six-axis motion system, which has the capacity to shake a car at 10 Hz. The cars are positioned in each of the six DOF by a combination of the extension or contraction of the six legs. They can roll, pitch, or yaw as much as 20° left or right or up and down, and move as much as ±3 in. in any of the other three axes.
Although the actuators’ full stroke is only about 6 in., that’s not significant “because the motion system transmits acceleration, not displacement, cues,” Jacobs says. “We have tricks we learned doing defense work to create false cues. For example, I can give a significant centrifugal-force cue in a sustained turn without large amplitudes in the motion system.”
Tricks are vital because a motion system cannot completely duplicate actual racing. “If you brake hard in a real Indy car, you experience about 3.5 to 4 g of negative acceleration, and when you step on the gas you get almost 2 g of positive acceleration,” Jacobs points out. “No motion system can generate those forces for more than a few miliseconds, because you run out of travel space. So you need to employ tricks that create the impression of sustained acceleration or either linear or rotational acceleration. Simulation happens in the mind, and people end up with a sensation their brain interprets as sustained acceleration. The simulation doesn’t have to be perfect, but it has to be good enough that it’s a believable experience and there are no conflicts.”
With Illusion’s interactive Indy-car simulated ride, the mathematics are so intricate that the computer model it runs is evaluated 500 times a second. “We do it that fast because at 200 miles an hour the car moves about 3 inches in one five-hundredth of a second. You want to be sure you detect a collision with a wall or another car before you penetrate into the wall or car by more than that, before people see it. This dictates a fast calculation interval,” Jacobs says.
Cues must agree
In all these simulation experiences, care is taken to avoid users feeling nausea. “Motion sickness is created by a number of factors, but probably the most important is how closely the cues that come through your different senses can agree. If your eyes tell you one thing and your inner ear says something else, that sends a big alarm to the brain and produces nausea,” Jacobs says. “We have to reduce the time delay between the onset of the different cues as much as we can. That’s why, for a given event, we have the visual, sound, and motion all start at exactly the same time.”
Jacobs does not agree that the coordination of motion base and screen movement is necessarily more significant than the number of degrees of freedom in ride simulation. “Both are important,” he says. “Timing is critical, but there are things we can do with six axes that can’t be duplicated with anything less. A typical three-axis system has pitch, roll, and heave, but suppose your car is coming out of a curve on the track and you lose control and hit the wall. One important cue you would feel immediately would be a jerk left or right, or yaw. That happens frequently in racing, and you can’t present it in a three-axis system.”
The Illusion SpeedSport system is priced at around $180,000 a car. For power, the simulators rely on a small group of off-the-shelf PCs, linked so the system can be easily and inexpensively upgraded or changed to other applications.
After the race, each driver receives a detailed printout with race statistics and tips on improving future performance. The company plans to extend this technology to vehicles other than race cars. It also intends to link different sites, so teams in distant cities could compete against each other, for example.
Finally, says Jacobs, “in military simulators we have networked live activity into the simulated world. So in the next Indy 500, for example, we could capture the positions of actual cars on the track in real time, map them into a virtual model of the Indy track, and let you enter as the 34th car in the race. That would be really exciting.”
Simulated golf
Simulation in other sports is improving and spreading, too. With an indoor computerized golf simulator, for example, a golfer can “play” a famous course, which appears courtesy of computer graphics on a screen several feet in front of him. Using a real club, a golfer hits a real ball into the screen. Almost instantly, sensors measure its force and direction, the computer calculates almost precisely where the ball would have landed on the actual course, and this information is then displayed on the screen. This is done for every shot.
Full Swing Golf Inc., San Diego, is the best-known developer of such games. With its simulator, players hit from anywhere inside a 16 3 12.5-ft enclosure into a 10 3 12-ft screen. An overhead projector beams a digital rendering of one of 21 well-known courses. For each hole, players first get an overhead view of the entire hole, showing distances and hazards. The scene then changes to a player’s-eye view. An infrared tracking system calculates the distance, velocity, and spin of a hit ball, and a projection of the ball in flight is shown on screen from the point of impact. Wind direction and speed and the like are calculated, and the virtual ball is subject to all the hazards of real golf. It will bounce off trees, splash into water, and plop into sand traps, as well as roll safely onto the green.
Following each stroke and ball-flight simulation, statistical information reappears on screen, telling how far the ball was hit and how far it is from the hole. The scene then shifts to a view of the course from the new lie. Every time a particular player’s turn to hit comes up, the screen view switches to the point where his or her last shot wound up. Once on the green, the player putts across the artificial grass floor of the simulator into the screen, and a simulated ball continues on into the picture. A contoured grid shows the exact slope of the green, if desired.
Access Software of Salt Lake City developed the program for this simulator, basing it on its Links 386 Pro golf game for PCs. It used topographical maps and aerial photos of the actual courses to reproduce every dip and tree. Graphics were enhanced for the 80486-based simulator, which uses a Panasonic high-resolution video projector. Over $30,000 was spent digitizing each golf course.
Full Swing Golf’s infrared tracking system uses two parallel rings of emitters and sensors placed 3 ft apart and about 7 ft from the tee. Each ring contains 20 infrared emitters and 700 receptors, spaced 1.5 in. apart. Information from the receptors is processed on a Texas Instruments board connected to the simulator’s computer. This data is passed to the Access system, translating player hits into screen action.
The custom-designed, ball-tracking system performs 20 million calculations/sec. Ball direction is figured by determining the points in space where the ball crosses the sensor planes. Speed is determined by measuring the travel time of the ball between planes. Ball spin, which causes hooks and slices, is calculated from where the ball recrosses the second plane when it bounces off the screen. Ball flight can be duplicated to within a few inches or at most a couple of feet, and ball speed is accurate to within 0.1 mph, the company says. One of its installations — including enclosure, hardware, and software — typically runs about $45,000.
Baseball, too
The Designated Hitter Game developed by Sports Simulation Inc., Pleasantville, N.Y., uses similar technology. A batter swings a real bat and hits a real ball into a screen, and the computer-controlled projected video image shows where the ball ends up on the major league field on screen. Even appropriate action of the fielders is displayed.
With this game, video of a life-size pitcher appears on the 11 3 16-ft screen, 21 ft in front of the batter. At the pitcher’s release point, a real ball is thrown from a pitching machine through a small hole in the middle of the screen. The ball-tracking system is a sequence of triggers that let two video cameras “see” the ball leaving the bat.
Before the pitch, however, a sensor tells the Pentium-based computer to roll the video of the pitcher’s windup, so the real ball is released at the same time the virtual pitcher reaches his release point. As the ball nears home plate, it triggers a row of floor sensors which activate a microphone above and behind the plate, to listen for contact of ball and bat. If contact is made, the mike triggers the cameras to “watch” for the ball leaving the hitting zone. The cameras, located opposite each other and synchronized to take a rapid series of pictures, capture a mirror image of the hit by picking up a streak of movement. This information is then sent to the computer, which analyzes it and projects a virtual ball to continue the flight of the real one. It also selects, from video of fielders making various movements, the appropriate defensive responses as well as the progress of runners on base.
The pitching machine, which can be programmed to throw at any speed from 25 to 33 mph, consistently throws strikes. Thus, if no contact is heard, the video umpire calls a strike. If contact is heard but the cameras don’t spot the ball, he calls a foul ball.
Sports Simulation plans to introduce a new game called Multisport Stadium this spring. One of its first interactive sports will involve kicking a real soccer ball against a virtual goalie on a screen. The other will involve pitching a real baseball against a screen showing a virtual batter, catcher, and umpire. Hockey, football, and tennis also are scheduled to be released this year.