• The creators of iQuarium, a virtual underwater environment that shows how fish swim, try out the interactive exhibit in the Hart Nautical Gallery. Left to right: Aaron Sokoloski, a junior in mechanical engineering; Audrey Roy, a senior in electrical engineering and computer science; and Katie Wasserman, a senior in ocean engineering.

    Photo / Donna Coveney

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  • iQuarium shows water particles spin off in colorful ribbons of vortices created by the movement of a tuna's tail.

    Photo / Donna Coveney

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Fishy fun with fluid dynamics

A hands-on, student-made museum exhibit teaches visitors about fluid flow as they move like scuba divers through a virtual underwater environment and interact with realistic-looking animated fish.

This fun look at the science behind how fish swim is called iQuarium--a virtual aquarium that uses the same sophisticated 3-D animation software that makes Xbox computer games so realistic. Instead of hunting down commandos with AK-47s, iQuarium users chase bluefin tuna around an idyllic underwater environment, watching water particles spin off the colorful ribbons of vortices created by the flicks of their tails.

The exhibit--an 8-foot-by-4-foot custom-built kiosk with a display on an LCD screen controlled by a luminescent blue trackball and buttons that allow you to zoom in or out, get background information and change the kind of fish you're watching--will open in the Hart Nautical Gallery in Building 5 on Friday, Feb. 6. It will be on permanent display as part of the gallery's ocean engineering exhibit, and its student creators--Katie Wasserman, Audrey Roy and Aaron Sokoloski--are planning to expand its capabilities over time.

Roy, a junior in electrical engineering and computer science, said that thanks to a webcam mounted above the display and sensors hidden under it, the fish also will respond to the movements of people approaching and standing in front of the "tank."

"iQuarium will forever change the way people look at fish," said Wasserman, a senior in ocean engineering who is heading the project. "They'll notice the subtleties of fish motion and start thinking like ocean engineers." iQuarium's colorful and dramatic computer graphics will allow people to see and appreciate details that are very difficult to see outside a laboratory, she said.

"Hydrodynamics is an area of active research, with many fundamental discoveries yet to be made," said Wasserman. "For one thing, it determines how fast ocean vehicles will go. Ocean vehicles enable scientific discovery, international shipping and transportation.

"The coolest thing about iQuarium is that it brings hydrodynamics to a place where non-technical people are going to see it. It brings ocean engineering into the public imagination," Wasserman said.

Another ocean engineering project that caught the public's attention in recent years is RoboTuna, a robotic fish that uses the same fluid dynamics as a biological fish. Engineers hope RoboTuna and other initiatives that mimic nature will show them how to make oceangoing vessels that can travel with more efficiency and maneuverability.

To help see the swirling patterns of water (known as vortices) created by swimming fish, scientists and engineers use flow field visualization techniques. One technique involves putting colored particles in the water and watching their movements; another calculates the velocity of water particles as they pass certain points. iQuarium shows off both techniques through its colorful simulations of the flows in the wake of the animated fish. The simulations are based on data about live swimming fish collected painstakingly by researchers using tow tanks and water tunnels.

To create iQuarium's display of four bluefin tuna and four giant danio (the danio is actually a relatively small freshwater fish), Sokoloski, a junior in mechanical engineering, used C++ and taught himself DirectX, Microsoft's 3-D graphics library used for Xbox games like Homeworld2 and Raven Shield. "This is the first time anyone has taken that technology and applied it to render real flow field data instantly," Wasserman said.

"This project takes complex research and presents it in a playful way that is engaging for all ages," said Kurt Hasselbalch, curator of the Hart Nautical Collections. "No interactive display anywhere in this city is as cool as iQuarium, and it's perfect for our MIT ocean engineering exhibit."

The iQuarium fish are a lot smarter than those in the virtual fishtank at the Boston Museum of Science, according to Wasserman. For one thing, the display is far more realistic. Instead of cartoonlike fish, the iQuarium fish are true to nature (although the saltwater tuna would never really swim alongside the freshwater danio). You can see sunlight filtering through the pristine water, and the white sand looks like you could sink your hand into it. "We're all about real science, real fluid flow and real species of fish," she said.

The project is funded by a $30,000 grant from iCampus, the MIT/Microsoft Research alliance. This partnership, which began in 1999, aims to revolutionize the practice of higher education with the tools of information technology.

A version of this article appeared in MIT Tech Talk on February 4, 2004.

Topics: Media Lab

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