Sketchpad : A Man-Machine Graphical Communication System

Written in 1963, Sutherland's Sketchpad system and resulting paper revolutionized the field of computer science. Sutherland's work was particularly unique as a new method of computer-human interaction where input was taken in through the newly invented light pen to construct drawings on an special interactive monitor screen. At the time, anything other than textual keyboard input was unheard of. In fact, Sutherland's Sketchpad introduced a completely new idea into the computer science community: Graphical User Interfaces. (You know, just as a side product.)

In addition to simply drawing shapes, Sketchpad enabled the user to establish and manipulate constraints for the lines and objects that were drawn, save those shapes and associated constraints to a library, reuse them through copying, and even merge those shapes and properties to create new classes of objects. In creating a generalized and abstract system for defining objects, Sutherland in-effect created* the modern concept of object oriented programming! Even more impressive is the fact that Sutherland had no language support for defining objects or classes or inheritance or anything like that. By 1963, C, not to mention C++ (C with classes), hadn't even been invented yet. "High level" programming languages like Fortran, LISP, and Algol were relatively new. In his paper, Sutherland clearly indicates the low level nature of the workings of his program when he says things like, "...operations are implemented by short sections of program defined as MACRO instructions in the compiler language..." and "...As parts of the drawing are deleted, the registers which were used to represent them are free." Sutherland also stresses the important of now commonly known benefits of the object-oriented programming paradigm in a section of the paper named, "Generic structure, hierarchies," when he said that, "Without a generic structure it would be almost impossible to add the instructions required to handle a new type of element."

Sketchpad in use

Sutherland using the TX-2
running Sketchpad

Sutherland also touched on gestures for his pen based interface when he mentions that the drawing ends by "flicking" the pen faster than the system can track it. The paper even touches on aspects of graphics and visualization when he talks about line and circle generation, magnification of pictures, and translation of figures.

Sutherland also discussed two very different forms of now common computer usage giving examples of how his Sketchpad system was being used.

1. Computer Aided Design (CAD)
• Since his drawing system could reproduce shapes and create and manipulate systems of constraints, Sutherland used his system as a way of designing bridges within a set of resource and physical constraints.

Bridge made in Sketchpad

2. Artistic Drawings

• While our modern society may take creating art through computers for granted in the forms of digital image creation with photoshop, video games through development engines and kits such as Unity3d, or even music through programs like FruityLoops, creating art through computers was almost unthinkable in 1963. Despite this, Sutherland discusses creating animated images.

Artistic drawing "Nefertite"
 and component parts
made in Sketchpad

To top it all off, Sutherland, in discussing future work, casually mentions future applications like direct 3D object creation/manipulation, 2D to 3D object transformations, and some potential work in the yet to be created field computer vision.

For his work with SketchPad, Sutherland has received the Turning Award in 1988 and the Kyoto Award in 2012.

*Ideas similar to object-oriented programming had been around MIT in the field of artificial intelligence, particularly around LISP. Later in 1967, Simula 67 introduced objects as a programming concept.

Cited work:
Sketchpad a man-machine graphical communication system, Ivan E. Sutherland, Consultant, Lincoln Laboratory, Massachusetts Institute of Technology, DAC '64 Proceedings of the SHARE design automation workshop, Pages 6.329 - 6.346, ACM New York, NY, USA ©1964