Issue link: https://digital.copcomm.com/i/18322
Viewpoint ■ ■ ■ ■ sound from these sources were computed in parallel. Sound radiation in the water domain was computed fi rst, and then sound radia- tion in the air domain was computed so that the normal velocity of the sound wave could match with that already computed in the wa- ter domain on the interface. Again, virtual sound sources, such as multi- poles, were used to approximate the sound waves. What’s interesting is that all these procedures were included in one fl uid sim that produces the graphics. It enabled a much higher level of syn- chronization compared to those from previous sound-rendering works. T e graphics generated using a cutting-edge fl uid simulation were in- credibly realistic, but the accompanying sound, which was produced at each step by algorithms working together with those that were producing the graphics, greatly increased the realism and be- lievability of the animation. It was the beauty of physically based synchronization, and it strongly impressed the audience. T e work on fracture sounds included an- other challenge. T e progress of sound render- ing had focused on making the sound produced by one object or phenomena more realistic, but when the number of sound-producing objects pling multiple types of objects and phenomena (fl uid, solid, and so forth). Ultimately, the chal- lenge is to satisfactorily synchronize sound and graphics in any arbitrary scene. T e series of sound works, such as water The realistic hair color was generated using a physically based hair refl ectance model whose parameters were recovered from photos of real human hair. The images were rendered with fl ashlight and image-based lighting. is increased, there are all kinds of added chal- lenges. T e fi rst challenge was to synthesize fracture sounds that start with one rigid-body sound model and then rapidly produce a large number of sound models in unpredictable ways. Even after this problem was solved, there still remained more complex cases, such as cou- and fracture, were planned as part of a project called “Sound Rendering” at Cornell Universi- ty. T e ensuing feedback from various industry sectors led the researchers to believe that tradi- tional methodologies, such as using recorded sounds, are still prevalent and that the revo- lution needs time. However, sound rendering is evolving rapidly, as we have seen, whereas what people expect for computer graphics and industry is also steadily changing. T erefore, the process could be viewed as a journey until the bridging of sound and graphics can meet with fruitful application results. CG researchers always have been enthusias- tic when it comes to making magical phenom- ena happen. Many magical scenes we see in fi lms and games today were brought about by image-based technologies that started with the concept of bridging photographs and CG. It will be exciting to see what kind of magic can be achieved in the future through undiscov- ered methods of bridging technologies. ■ CHECK OUT COMPUTER GRAPHICS WORLD ONLINE EXCLUSIVES BLOGS VIDEOS BREAKING NEWS DIGITAL EDITION GALLERY MORE! www.cgw.com October 2010 11 ONLINE Courtesy Arno Zinke.