Check out Van Dam's panel Look Ma! Four Hands! New Models for Interacting with 3D Models.




















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Interactivity Takes Shape


Andy van Dam has been involved in interactive graphics for over 30 years. In 1964, he saw Ivan Sutherland's film about Sketchpad, the first 2D interactive graphics system that used a light pen to manipulate objects on a computer screen. Van Dam was inspired, but his university did not have an interactive graphics system. So he used an alpha-numeric line printer as his output device and couldn't do interaction. He simulated vector graphics output on the line printer. He didn't acquire an interactive vector graphics system until several years later, when he was a faculty member at Brown University.

In the early 1970s, researchers at Xerox's Palo Alto Research Center (PARC) invented the Alto, a prototype personal workstation that stored a rafter graphics image in a bitmap. Bitmapped rafter graphics "is an inherently more powerful medium than vector graphics," van Dam says. The Mac's Graphical User Interface (GUI) borrowed from ideas developed at PARC, and in 1984, "the beauty of Mac was to make that power available at reasonable prices." Later, this was imitated by Microsoft in its Windows GUI. Therefore, people today still work and play with the Alto's direct descendents. The steady advances in processors, memory and rafter graphics hardware have allowed graphics to change from "what used to be a research vehicle for a handful of researchers," into something that's "accessible to even pre-schoolers," van Dam notes. "This [change] is revolutionary."

But the conventional mouse most people use today only works well for two-dimensional graphics, van Dam says, and too many people have not been exposed to the interface advantages of other interaction devices, such as physical sliders, dial boxes and 3D joysticks. Currently at Brown University, his group is working on interfaces based on the computer recognizing the user's gestures, -- through a stylus or a mouse -- more like freestyle writing on a pad rather than typing on a keyboard. "We are two-handed creatures that can use both hands, listen, and talk at the same time, so we should be able to interact like that with computers." Right now, he says, "computers are mostly deaf, dumb, and blind, and we want them to interact with us much more like real assistants."

One project the Brown researchers are working on is a music drawing program. Composers sketch notes on a tablet with a pen, and the computer recognizes the notes, draws them on a staff, and plays the music as they sketch. Similarly, in a 3D graphics project, the computer "recognizes the geometry in the gesture, then uses built-in rules," essentially to fill in the blanks, van Dam says. When a user draws two angled lines connected together at one end, for example, the sketch is interpreted as a pyramid; two parallel lines become a cylinder.

Participants playing at the HoloWall.


Modeling | Rendering | Animation | Interaction | Virtual Reality | Synthetic Actors