MEDICAL students who long to get their hands inside a body, and architects who want to show city planners how their new tower will fit in with an old town centre will soon be able to do so without touching a scalpel or a model. It's all thanks to a new display tool that makes 3D images spring out of a tabletop.
The Immersive Workbench looks like a large glass-topped table. Three-dimensional images appear on top of the table to viewers wearing special glasses. One person uses either a 3D mouse or a dataglove to move the images around.
The display is being developed by researchers at three organisations. the German National Research Center for Information Technology (GMD) in Sankt Augustin, Stanford University in California and Fakespace, a company in Silicon Valley that specialises in virtual reality computer interfaces.
The 3D effect is achieved by a specialised computer from Silicon Graphics. This stores all the images and alternates between sending images for the left eye and those for the right to a digital projector. The system sends 120 images a second to the projector.60 for the left eye and 60 for the right.
The viewing glasses have shutters synchronised to open and close as the images are projected onto the glass table. So when the left eye image is projected the right eye is covered. This makes the image appear on the table rather than inside it.
Workbench will be useful for surgeons who want to plan operations based on CAT scans of a patient's body, says David Eggleston, a vice-president of Fakespace. The system could also be used by architects at planning meetings. The US military is looking at the Workbench for planning training manoeuvres. Demonstrations of these applications were on display at SIGGRAPH, the computer graphics and interactive computing conference, which was held in New Orleans earlier this month.
Eggleston says one of the hardest achievements is getting the hardware and software to work together in a way that seems natural. When the viewer points at the part of the image they want to concentrate on, the image should change quickly and smoothly. "You want to maintain the resolution and perspective," he says.