Big bang meets graphics at confab

Astronomical data, computer graphics and the emerging field of "conformal geometric algebra" are giving researchers a clearer picture of the shape of the universe, according to Anthony Lasenby, a professor at Cambridge University and the keynote speaker at Siggraph, an annual conference sponsored by the Association for Computing Machinery that highlights advances in computer graphics.

"The universe is actually pretty close to flat at the moment," Lasenby said Monday. "We may be close to understanding the geometry of the universe."

The four-day convention is dedicated to outlining new techniques for recreating three (and four and five) dimensional worlds through equations.

"Rendering is the modeling of the appearance of the everyday world," said Pat Hanrahan, a professor at Stanford University and this year's winner of ACM's Steven Anson Coons Award for Outstanding Creative Contributions to Computer Graphics. "We just don't manipulate the final physical media like sculpting or painting."

Although computer graphics have already attained a high degree of realism, they remain one of the hotbeds of research. Describing why water, trees or other natural phenomena look the way they do is a challenge that scientists had abandoned in the past because of the complexity of the task and the immense number of calculations involved, Hanrahan said.

Now, because of the calculating power of modern computers, light patterns and physical movement can be understood and simulated.

Some researchers are looking at the possibility of changing the basic structure of computer graphics, which over time could lead to more realistic simulations. Currently, graphics are created by cutting up three-dimensional objects and surfaces into triangles, Jim Blinn, a graphics fellow at Microsoft Research and one of the pioneers of computerized graphics, said in an interview.

Blinn is working on ways to enable computers to handle smooth surfaces as smooth surfaces, rather than as thousands of triangles. Equations for depicting smooth surfaces already exist, but Blinn is working on ways to reduce those complex formulas into calculations that can be more easily handled by modern hardware. In the end, smooth-surface calculations may be combined with traditional polygon rendering.

"There is this whole industry in the graphics business of taking an algorithm and somehow wedging it into the hardware," Blinn said. "That's good, but it also limits you a bit on what you expect to be able to get out of it."

Among other projects, Blinn developed the underlying graphics technology for the PBS series "Cosmos." He also created a simulation of the Voyager I spaceship's journey to Jupiter for the Jet Propulsion Laboratory.

"People looked at that and said, 'Wow. That is the most realistic Jupiter I have ever seen,' which is nice, but that's because they don't look at Jupiter all that much," Blinn said.

Many of the exhibitors and lecturers at the conference come from the entertainment field. Graphic designers from Industrial Light and Magic will demonstrate on Monday how the studio created different characters and special effects. Thursday, designers from Pixar Animation will give a behind-the-scenes look at the computer-generated film "Finding Nemo."

Back to the universe
Research institutions, however, are represented as well. Siggraph is one of the few trade shows that features booths from Harvard University, Purdue University, the University of Southern California and the Rochester Institute of Technology.

Lasenby's keynote reflected that side of the conference. The Cambridge research focused on correlating data about ancient radiation patterns in the universe to computerized geometric models.

Right now, radiation patterns indicate that the universe--which got its start 14 billion years ago with the big bang--is fairly planar. That's good news. If the universe were spherical, we would likely be facing the "Big Crunch," or complete implosion, in a few billion years.

The planar shape, however, won't likely last. In a purely flat universe, the expansion of the universe would be slowing down. Instead, it is accelerating, Lasenby noted. This data indicates that the universe may be curling up into a cone, which would lead to an infinite universe. Some data also indicates that a small portion of the universe is finite, he added.