February 2005

Synopsis: Information Technology

Continued from page 1

By Monya Baker (edit)

Once More, with Volume
Hand gestures control computer graphics

Context: Video games, design software, and scientific visualization technologies routinely use 3-D graphics. Typically, users interact with 3-D graphics on flat computer screens and cannot grab, move, or rotate graphical representations as they can real physical objects. Even the most advanced stereoscopic displays, like those used in virtual-reality systems, require head-mounted displays, which restrict viewers' range of motion, obstruct peripheral vision, and cause discomfort. Now, researchers at the University of Toronto have created a system that frees 3-D graphics from such constraints.

Methods and Results: Key to the system is a "volumetric" display, one that lets multiple users view graphics from any ­angle without wearing headgear. Tovi Grossman and his colleagues used a swept-volume display, which spins a series of 2-D images around an axis fast enough that humans perceive them as a 3-D image. The researchers created a way for users to manually interact with their display, which is housed in a clear plastic dome. Cameras track special rings worn by the users, who can select 3-D objects by pointing at them and drag them by moving their fingers across the display sphere. Using both hands, users can stretch or shrink objects, or specify the axis about which an object should rotate.

Why it Matters: While the new display does not provide sensory feedback, it permits the control of 3-D graphics through hand gestures similar to those whereby people manipulate real objects. The technology eliminates the need for joysticks or virtual representations of users and paves the way for 3-D graphics applications that anyone can use with minimal training. Volu­metric displays, once found only in expensive research prototypes, have become commercially available. The Toronto researchers' interface could hasten the day that they are routinely used by scientists designing drug molecules, doctors planning surgeries, architects, engineers, and, of course, gamers.

Source: Grossman, T., D. Wigdor, and R. Balakrishnan. 2004. Multi-finger gestural interaction with 3D volumetric displays. Proceedings of the ACM Symposium on User Interface Software and Technology, pp. 61-70.