Touring the Emerging Technologies exhibits at Siggraph

BOSTON--While people may not really need a virtual fish tank, the technology needed to make one may have important applications.

The Emerging Technologies exhibit, part of Siggraph 2006, mixed the practical with the fantastical to explain new achievements in computer graphics.

Cubee, a virtual 3D fish tank, hangs from the ceiling, suspended by bungee cords. It can be shaken or rotated by the viewer and will react with the correct perspective or corresponding motion. While the Cubee image can be seen by anyone, the system includes a sensor-equipped crown that, when worn by a viewer, directs the perspective to that viewer as she or he moves around. According to Florian Vogt, a project collaborator from the University of British Columbia, the open-source software developed for the project by his group is already being used for anatomical modeling in dentistry and for viewing objects rendered by computer-assisted design.

Toshio Iwai attracted many visitors to Morphovision--his glass box containing a model house than can be visually manipulated into different shapes. In the same way that a photocopy will distort if you move the paper while it is being scanned, so does the look of a 3D object being scanned while the object spins. In this case, a scanning projector and mirrors make the distortion visible to the naked eye. Viewers can make the house virtually melt or break apart by changing the shape of the scanning light beam. The result: The object looks like a holographic image, not something tangible.

In another Emerging Technologies exhibit, called the Bubble Cosmos, images projected on soap bubbles containing smoke float up from a box of lights and cameras. Sensors in the cameras track the round shape of the bubbles. If a bubble is popped while it is lit up with an image (which means the bubble is directly over the sensor), the machine rewards the observer with a cartoon-like popping sound, and a different image projected on the lingering smoke.

And, while the results may not yet be as striking as the depiction of Princess Leia asking for help, more scientists have attempted to re-create the holographic image. True 3D Display focuses laser light in single points over ionized, heated air. Viewling the display is like viewing an oscilloscope, only instead of a two-dimensional view of signal voltages, you see shapes in the air.

A spokesman for the project said that the group plans to apply the technology to create aerial graphics, such as advertisements or emergency messages. Some people may not be able to get past the loud "bug zapping" sound caused by lasers pulsating 300 times per second. Also, aside from irritation with the noise, bystanders were concerned that the demonstrators were wearing protective goggles while visitors to the exhibit looked on with naked eyes.