Issue link: https://digital.copcomm.com/i/14320
Scientific Visualization n n n n Real-time Productions Lastly, the planetarium also runs real-time fly- throughs using Uniview running on an HP cluster that is not part of the server setup. “Be- cause it is real time, it plays like a video game. You can go anywhere you want to go,” says Neafus. In fact, the planetarium does a daily program that allows the public to walk in and decide where in the universe they would like to visit, “and we take them there on the fly. Nothing is pre-rendered for that experience.” In addition to both workstations dedicated to the experimental work, all six workstations in the cluster also contain a complete copy of Uniview for every node that lives on each hard drive, so the cluster can efficiently access the data (more than 2gb per copy). Although every machine in the cluster is running a par- allel copy of Uniview, each one is looking in a different direction. “Te trick is to make them all run together and call up the data simulta- neously,” says Neafus. “Tat is the beauty of the architecture.” By running the software in this type of set- up, the group, for instance, can call up a map of Earth, as well as a weather map, bring that is to be sure that each machine’s output rate can keep up with the robust data. While the RAM and motherboard are important, the brunt of the demand is placed on the video card, to keep up with the refresh rate and stay synchronized. Fast Forward “Installed in 2007, the current architecture is already a bit old,” points out Neafus. “We are looking at an update.” Currently, the output from each computer in the dome is a rect- angular 1440 x 1050 image, which is then warped into the curved shape to match the dome using a proprietary black-box solution (from Global Immersion), and then passed on to each projector—basically, the first half of the geometric blend process. “Our architec- ture makes it simple to have multiple image generators upstream and switch among the clusters because everything is going into that black box, and it blends well up on the dome,” Neafus says. Newer architecture, however, is accomplishing that on the video cards. In so far as the 2007 upgrade to HP workstations, the staff witnessed a dramatic son, but a few years back, it was a nightmare.” To show just how far things have pro- gressed, Neafus points out that the older SGI system allowed just 4tb of storage. “In the first production we put together, we could barely accommodate one complete show in terms of development. We didn’t have enough room to do another program or even a backup. So, it was a big bottleneck.” In contrast, today the group is using a 15tb EMC RAID for hold- ing the daily work, and the HP workstations hold 1.5tb each in the offline systems; they also rely on more than a dozen 1tb USB por- table drives for archiving, and all of that is net- worked onto a gigabyte network for sharing copy back and forth. “Yeah, four years ago it was a real bottle- neck. Today, moving 4tb is trivial by compari- son,” Neafus says. Even so, the current tool set is enabling new and exciting productions. Not long ago, lo- cal university students created moving digital backdrops for 17 scenes in their production of “Joan of Arc” that were projected up on the dome while the performers were on stage. “Students had the chance to experiment with With its state-of-the-art digital setup, the Gates Planetarium is able to create its own space shows, including the museum-produced Black Holes. in as a spherical texture map, and copy it to all six nodes so they all have a copy of the same texture map. “As we are flying through, the system is calling up all the data at once, and the six machines are blending the imagery to- gether as full hemisphere projections,” Neafus explains. Tat imagery usually comes directly from the origination point—say, a NASA satellite. As a result, the crew has shown, for instance, the affected area of the recent oil spill in the Gulf of Mexico and the volcanic ash cloud that recently plagued Europe. How far can the group push these visualiza- tions? Basically, as far as the known universe, to as close as sub-meter resolution. Te key improvement in rendering and processing speed, on average 50 times faster. Currently, the group can access and modify frames in ap- proximately 10 seconds, compared to 60 sec- onds previously, though that can still hinder real-time scenarios. In Neafus’s opinion, the biggest challenge that comes with this type of dome work is the scale of the files and managing those files. “You are dealing with six times the demand you would have for HD editing,” he says, re- ferring to the six clusters in the dome. “Tat requires a robust capability for throughput, storage, and network storage. For the past few years, prices for that have come down to rea- the different visualizations and the timing us- ing our offline system,” Neafus says. Another unique production was “Live Out Tere,” a musical performance given by museum cura- tors. In these instances, the imagery was created from scratch by the users; sometimes it is done in Autodesk Maya, other times in Cinema 4D or other types of common DCC software. “We want to increase the pool of users who can create this type of work, and make sure they get a quality experience out of it,” says Neafus. “Te museum’s goal is to increase scientific literacy and to continue pushing the envelope in terms of programming that en- gages our audiences.” n Karen Moltenbrey is the chief editor of Computer Graphics World. July 2010 47