Innovation: Physics brings realism to virtual reality
By Colin Barras Innovation is our regular column that highlights the latest emerging technological ideas and where they may lead. Computer games have come a long way from the pixelated graphics of the 1980s to the more polished characters of today. But the inexorable creep of Moore’s Law has now taken us to the brink of further giant changes. The latest multi-core processors and some smart software allow techniques used by physicists and engineers to simulate the real world in extreme detail to be used to create virtual worlds governed by real physics, rather than the simplified versions used today. The video above shows how the results are streets ahead of the standard graphics of today. One expert evens predicts that such techniques could be used to create Matrix-like virtual worlds indistinguishable from reality within just a few years. A centuries old physics technique called ray tracing, used to calculate how rays of light would behave in a particular environment, is one method receiving much attention. “We shoot a bunch of rays at every pixel in the scene and determine what colour it should appear by considering what type of surface it hits,” says Daniel Pohl at Intel labs in Santa Clara, California. The technique also takes into account the way each ray reflects off, or refracts through, an object as it would in the real world. Pohl can generate a virtual world containing some 2 to 3 million rays on every screen that users can move through in real time, with an animation rate of 20 frames per second. The experience is impressive (see video), but far from full screen at just 512 pixels square. “If you want true photorealism you’d need hundreds of rays per pixel,” says Pohl. The current demo has around 10 rays per pixel. The computing power that is now available makes it feasible to simulate physical processes from the smallest scale upwards, rather than trying to approximate their overall effect. For example, when computer scientist Jonathan Kaldor at Cornell University, Ithaca, New York, wanted to create virtual fabrics better those that had gone before he did something unthinkable just a few years ago. “We decided to start from the [individual] yarns. It sounds crazy but it actually works.” Kaldor presented his work at the Siggraph conference in Los Angelese last year. Knitting garments like socks and scarves from virtual wool modelled on real-world yarn gives results that stretch and deform realistically no matter how close up the view. The results could also be used with a haptic interface to provide the feel of fabric. To add further realism, the team now plans to simulate the fuzz on the surface of each piece of yarn that adds friction between threads. Simulating physical processes more accurately can also improve sound effects, as another Cornell group recently showed. Doug James and Changxi Zheng, have simulated the tiny bubbles responsible for the distinctive sounds of flowing and splashing water. By modelling those bubbles, and the way they vibrate and burst, the pair could generate a strikingly real virtual sound. Although not yet possible in real time, James told New Scientist he thinks it should be feasible. The pair will present the work at the Siggraph conference in New Orleans in August. Other researchers in the field are similarly optimistic that realism will increase rapidly. We are starting to see what is possible when you replicate some of the fundamental forces that make the world around us, and before too long that means it will be possible to build realistic worlds of our own. Read previous Innovation columns: Smartphones need smarter networks, Looking forward to the smarter smartphone, How can Microsoft’s full body gaming interface work?, Winning the cybersecrets armsrace, Software to track our emotional outbursts, Mind-reading headsets will change your brain, Harnessing spammers to advance AI, 100-mpg car contest under starters orders, The mobile future of the keyboard, A licence to print gadgets, What next after the megapixel wars?