Monday, May 21, 2007

Recreating the Feel of Water

Continued from page 1

By Rachel Ross

The kayaking simulation requires a much larger setup, including two projection screens. Images of the water surrounding the boat are projected onto a screen on the floor, while a second screen mounted in front of the user shows what's ahead, including rocks and bends in the river. The user holds a large rod that is roughly the length of a kayak paddle. Much like the ball in the fishing setup, this rod is suspended by motorized wires. These wires pull on the paddle to simulate the force of the water. By moving the rod against these forces, the user can steer the kayak.

Dobashi says that while there are some differences in the hardware, the basic equations used for the fishing and boating simulations are very similar. A paper outlining both projects was published in the May/June issue of the engineering journal Computer Graphics and Applications.

Bill Baxter is one of a handful of researchers who have also investigated fluid haptics. In 2004, he designed a virtual painting program as a graduate student at the University of North Carolina at Chapel Hill. Simulating a brush dipped in oil paint also involved a careful examination of fluid haptics. Having taken a ride in Dobashi's kayak, Baxter says that the precomputation approach makes a lot of sense: it overcomes the speed limitations of today's computer processors. "It's also a lot of fun," Baxter adds. But the system could still be improved, he says, to take into account more variables, such as the effects of tiny whirlpools created by spinning the paddle.

Dobashi admits that right now, the forces haven't been calculated for every possible rod and paddle position. He hopes to fill in those blanks and create two-player games so that kayakers can race.