Sketchpad, completed by Ivan Sutherland at MIT’s Lincoln Laboratory in 1963, was the first system to let a person draw and edit graphics interactively on a computer display. Running on the Lincoln TX-2, it presented the user with a screen and a light pen; pointing and gesturing with the pen created and manipulated lines, arcs, and shapes directly, rather than through punched cards or typed commands. It is the work that effectively founded the field of computer graphics.
The system was documented in Sutherland’s PhD thesis, “Sketchpad: A Man-Machine Graphical Communication System,” submitted to MIT in January 1963 and archived both in the MIT repository and as Cambridge Computer Laboratory technical report UCAM-CL-TR-574. The thesis describes far more than a drawing program. Sketchpad let the user impose constraints, such as making lines parallel, equal in length, or perpendicular, and then solved for a configuration satisfying them, so the drawing behaved like a model with enforced relationships rather than a static picture.
Several architectural ideas in Sketchpad were ahead of their time. It maintained a hierarchical data structure in which a defined shape, a master, could be instantiated repeatedly, with changes to the master propagating to every copy, an early form of what later became objects and instances. It used recursive procedures for geometric transformations and for traversing the structure, and it separated the abstract model of the drawing from its rendered appearance on the display.
Sketchpad’s influence is hard to overstate. It is cited as a direct ancestor of computer-aided design, of object-oriented programming, and of the graphical user interface that became universal decades later. The work was central to the citation when the Association for Computing Machinery awarded Sutherland the Turing Award in 1988, and it remains a touchstone demonstration that computers could be partners in visual, interactive design rather than just batch calculators.