VR-Disc: The Ultimate Virtual Reality
Department of Computer Science
University of North Carolina
Chapel Hill, NC 27599-3175
Figure 1 - The authors prepare to enter the Ultimate virtual experience
Computer graphics are rapidly pervading every aspect of modern life. The workplace, movie theatre, amusement park, and home are all seeing the effects of new virtual reality technology. It is only logical, then, that we should expect to see this exciting new paradigm on the Ultimate field. In this paper we demonstrate a system for immersing two players in a virtual Ultimate game. By wearing head-mounted displays driven by a sophisticated computer graphics engine, we are able to convincingly simulate the thrill of Ultimate without the associated risk of blowing out one’s ACL.
The authors, two graduate students in computer science at the University of North Carolina and avid members of the UNC Darkside Ultimate team, were tired of getting rained out. Sick of building virtual reality applications for useful tasks (visualizing molecules, architectural walkthroughs, and so on), we turned to our secret passion: Ultimate. Working late nights, concealing our work from our advisors, we delved deep into the subconscious desires of the Ultimate psyche. The results are nothing short of astounding. Join us on a trip into...
Originally the system used the advanced Pixel-Planes 5 graphics supercomputer to render the playing field and opposing team. Then we decided that was boring. Why play on a normal 70x40 yard ultimate field when you can play over a panoramic mountain vista? Figure 2 illustrates our playing field:
The players wear head-mounted displays (HMDs) that present a different view to each eye, thus generating stereoscopic depth of field. Each player's head is tracked; as a player's head swivels the computer pans the view to match what his or her eyes would see in the virtual world. The players use a specially treated 175 gram Discraft UltraStar (tm) disc which is tracked by a hybrid magneto-optical tracking algorithm developed by State et al .
2.2 Previous Work
(And if there were, we wouldn't admit it)
They're proprietary. Don't even ask.
4.0 Data Structures
Look, the details would bore you. Just trust us, it works, okay?
The results were tremendously, unbelievably, stupendously cool. Check out Figure 3 where Carl almost gets a point block on Dave's virtual forehand.
Or how about Figure 4, where Dave surveys the playing field contemplating his next throw.
Dave was actually able to suspend disbelief so well that he laid out for a virtual score (Figure 5). This brought the virtual crowd to its feet, but also left Dave in an awkward position as his virtual dive carried him into a very real desk. Dave is in stable condition and is expected to make a full recovery, but his experience raises an interesting safety issue for future scientists to grapple with.
6.0 Future Work
The greatest drawback to our system is the lack of tactile feedback to let the player really feel the virtual disc in his grip. We are currently experimenting with various haptic feedback devices such as the Sarcos force-feedback manipulator pictured in Figure 6. This device is a powered exoskeleton which fits over the user's arm and responds to the user's movement by simulating the feel of throwing and catching a disc. The Sarcos Arm is driven by 3000 pounds of hydraulic pressure: when Carl catches that disc, he's in for a surprise!
Carl is currently in serious condition but reports that he will still make it to practice for Fools.
Thanks to Subodh Kumar for taking the pictures. Thanks to Darkside Ultimate for a great year. Thanks to you for not telling our advisors that we did this on their payroll. This work was (unknowingly) supported by ARPA Contract #ADYDISCDEFOOLSDG28947230-6.
 State et al. Hybrid Magneto-Optical Tracking Algorithm for Dave and Carl. Proceedings of SIGGRAPH 97, Rapid Falls, MI.
 Luebke et al. How To Throw A Flick While Wearing A Headmount. UNC Technical Report #TR96-032.
 Erikson, C. How Not To Catch A Disc While Wearing Powered Equipment. UNC Technical Report #TR96-004.
 Azuma, Ron. How To Shoot Nerf Hoops With Unnerving Accuracy In The Graphics Lab. UNC Technical Report #TR95-003.