How did a 1963 PhD thesis become the ancestor of design software?

With a light pen, a screen and a program that understood geometry. In 1963, for his PhD thesis at MIT, supervised by Claude Shannon, Ivan Sutherland wrote Sketchpad, a program for an experimental computer called the TX-2. Drawing directly on the screen with a light pen, a user could sketch lines and shapes, tell the computer to hold a line at a fixed length or two lines at a fixed angle, and turn a drawing into a master whose copies all changed when the master changed. That is why Sketchpad is considered the ancestor of modern computer-aided design (CAD) programs.

It broke ground well beyond drawing. Sketchpad was the earliest program to use a complete graphical user interface, it had the first window-drawing program and clipping algorithm, which allowed zooming, and its masters and copies pioneered the idea of objects and instances in computing. It went on to inspire both the graphical user interface and object-oriented programming.

Sutherland was not working in a vacuum. Patrick Hanratty, sometimes called the father of CAD/CAM, had been writing CAD software for General Motors since 1961, and Sutherland's own thesis mentions a similar program at Bolt, Beranek and Newman and another, T-Square, written by MIT students in 1962. Still, very few programs can be called precedents for what he achieved, and a trade magazine said he broke new ground in computer modeling and visual simulation, the basis for computer graphics and CAD/CAM.

The hardware did not last. The TX-2 was an experimental machine whose hardware changed often, on Wednesdays according to Sutherland, and by 1975 the light pen and the screen Sketchpad had used were gone. The thesis, though, later earned Sutherland the Turing Award, in 1988.