Sketchpad

A program that allowed users to draw on a screen with a lightpen. It supported constraints (e.g. drawing a constrained

ellipse produced a circle). It also had some computer aideddesign features (e.g. computing loads on beams).

Sketchpad was the subject of Ivan E. Sutherland's 1963 MIT

PhD thesis, which opened the field of computer graphics. It

was the progenitor of computer drawing packages like MacDraw

or Adobe Illustrator. There is a film of Sketchpad in

action.

It solved constraints using value inference and introduced

the "ring" list structure.

["Sketchpad: A Man-Machine Graphical Communication System",

I.e. Sutherland, MIT Lincoln Lab, TR 296 (Jan 1963)].

[Sammet 1969, p. 678].

(1995-02-14)