DAC-1

DAC -1 ( Design Augmented by Computer ) was an early CAD (computer- aided design) system, which was introduced in 1964 by General Motors.

The DAC - 1 project, initially called "Digital Design", was started in 1959 by a five-member group. The aim was to develop a computer system to describe the geometry of motor vehicle bodies. As a computer, an IBM 704, which was programmed for the graphics output on an IBM -780 screen was used. For interactive operation served a chain printers, were wired in the five dials. The current position of the dials was read out and controlled the program execution.

The graphical input was performed using a photomultiplier tube. Drawings were first applied to a set through the IBM 780 plastic film. In that the points have been determined, at which the light of an image displayed by the screen light spot has been obscured, the drawings could be digitized. The digitized curves were smoothed by the computer program and approximated by cubic splines. By interpolation of multiple curves, a surface could be modeled similar to that presented later Coons patch. In 1960, the collaboration with IBM has been regulated under the project contract, whereby the system was supplemented by new hardware.