Staking the Pioneers: The
1960s to the 1990s
The richness of computer visualization today can be traced back to pioneering work, such as Ivan Sutherland's landmark doctoral dissertation from the early 1960s. As an NSF-supported graduate student at Massachusetts Institute of Technology (MIT), Sutherland developed a real-time line-drawing system that allowed a person to interact with the computer using a prototype light pen. While the research itself was supported in terms of both funds and computing resources by the Air Force through the MIT Lincoln Laboratory, the NSF fellowship helped make this graduate study possible. Sutherland credits NSF for the support it provided: "I feel good about NSF taking well-deserved credit for supporting my graduate education. Having independent NSF support was crucial to my ability to transfer to MIT from Caltech. MIT had seemed eager to have me in 1959, but was all the more willing to admit me in 1960 as a post-master's student because I brought NSF support with me."
Sutherland's Sketchpad introduced such new concepts as dynamic graphics, visual simulation, and pen tracking in a virtually unlimited coordinate system. The first computer drawing system, DAC-1 (Design Augmented by Computers), had been created in 1959 by General Motors and IBM. With it, the user could input various definitions of the three-dimensional characteristics of an automobile and view the computer-generated model from several perspectives. DAC-1 was unveiled publicly at the 1964 Joint Computer Conference, the same forum Sutherland had used in 1963 to unveil Sketchpad, which had the distinguishing feature of enabling the user to create a design interactively, right on the screen. His achievement was so significant that it took close to a decade for the field to realize all of its contributions.
Computer graphics was still too obscure a field to be a cover story in 1972, when Bernard Chern, who later retired as director of NSF's Division of Microelectronic Information Processing Systems, began a program to support the development of computer systems for representing objects in three dimensions. Chern assembled a stable of grantees, including many of the country's leading researchers in automation and modeling.
Among them was Herbert Voelcker, who recalls the state of the technology at the time he launched the computer modeling program at the University of Rochester: "Major advances in mechanical computer-assisted design were not possible because there were no mathematical and computational means for describing mechanical parts unambiguously
There were no accepted scientific foundations, almost no literature, and no acknowledged community of scholars and researchers
These early explorations were unsettling, but also challenging because they led us to try to build foundations for an emerging field."
Voelcker and his team were among the pioneers in computer-assisted design (CAD), which, for most of its history, had relied primarily on wireframe systems. Mimicking manual drafting, these computer programs build either two- or three-dimensional models of objects based on data supplied by users. While useful, the programs frequently result in ambiguous renderingsa rectangle might represent either a flat side or an open spaceand are fully capable of producing images that resemble the drawings of M.C. Escher, where continuous edges are a physical impossibility. Solid modeling, on the other hand, is based on the principles of solid geometry and uses unambiguous representations of solids.
In 1976, Voelcker's group unveiled one of the earliest prototype systems, called PADL, for Part and Assembly Description Language. For the next two decades, PADL and other solid modeling systems were constrained by heavy computational requirements, but as faster computers have come into their own, PADL descendants are now displacing wireframe modeling and drafting in the mechanical industries.
NSF-funded researchers at the University of Utah are taking computer drafting techniques even further, all the way to what is known as "from art to part." That is, they are creating a system that generates a finished metal product from a sketch of a mechanical object, by passing the prototyping stage all together.