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Tech Trends-Peek into a Nuclear Weapons Lab
February 1, 2006 By: Kenneth WongFakespace builds Stereoscopic Visualization Center for Los Alamos National Laboratory.
Every Once In a while, a team of scientists from Los Alamos National Laboratory, aka the Lab, is herded into what is known as the Cave, not too far from the White Rock hiking trails. They wear funny plastic goggles and don dainty little booties over their shoes. Once inside, they wait for an explosion to take place under their feet as they sip coffee.
The explosion is a computational simulation. The room, nicknamed La Cueva Grande (the Great Cave), is a 15' X 10' X 12' (WxLxH) immersive visualization center, built and installed with the help of Fakespace Systems (www.fakespace.com). Researchers involved in the ASC (Advanced Simulation and Computing) Program at the Lab use the immersive room to analyze the massive amount of data generated by the U.S. Nuclear Weapons Stockpile Stewardship Program. According to the Lab, this is at the cutting edge of an emerging third scientific method, or predictive science, which complements the classic methods of theory and experiment. Advances pioneered at the National Laboratories (Lawrence Livermore, Sandia and Los Alamos) on behalf of the U.S. Stockpile Stewardship Program will ultimately lead to adaptation in many scientific, engineering and commercial applications.
Step Inside
Steve Stringer, project leader at the Lab, modestly describes himself as "the soup-to-nuts guy." He explains the concept of the immersive room, borrowing an analogy from his colleague Bob Kares, a senior visualization scientist at the Lab. "When you're looking at a flat screen," says Stringer, "it's like looking through a picture window. You can tilt your head, you can look around, but you're not in the scene. When you go into the immersive room, it's like stepping through the window and into the world itself."
There are 33 projectors behind the wall, ceiling and floor screens, spraying out 43 million pixels into the room. Raw physics dance above, below and all around you as polygons and meshes (figure 1). Motion sensors track your movement, and the projectors flash the left-eye and the right-eye views in quick succession to create the stereoscopic depth effect. Jeff Brum, vice-president of business development and marketing at Fakespace, says, "Because you are wearing stereoscopic glasses, you do actually get the sense that images are coming off the screens and surrounding you just like a real-world environment. In a simulation like the ones at Los Alamos, you feel as if you are standing inside a nuclear reaction, an experience not possible any other way. For an automotive designer, the same kind of immersive display can be used, so that if you're sitting in the model of a vehicle, you feel that the steering wheel is actually in front of you and the armrest is on the side."
 Figure 1. A view of the immersive environment inside the visualization center installed at Los Alamos National Laboratory. |
Networking for the Cave
A single simulation session can produce as much as 650TB (terabytes) of data. To give a sense of scale, Stringer compares it to the entire collection of printed materials in the Library of Congress, which, he estimates, amounts to about 20TB. The visualization centers in the three National Laboratories are linked via secure broadband pipelines for remote collaboration. But 650TB is liable to choke any pipeline. "So we won't transfer that amount of data routinely," explains Stringer. "The company [Computational Engineering International] that supplies our visualization software [EnSight] has extended its client-server for us, and has made it commercially available for anyone to use. So if the data is hosted in California, they use a hierarchy of servers—basically servers of servers—to roll up the rendered data, not the raw computed data, and ship that across the country to another lab."
Collaboration inside the immersive room is the classic kind, where a team of experts comes together to solve a problem in the same physical space. Remote collaboration is technically possible, but according to Stringer, that working model may not be relevant to how the three National Laboratories operate, because each Lab's specific tasks, while complementary, are different from the others'.
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