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The ancestor of computer-aided design

May 13, 2022
by Mark Ollig

A computing inflection moment in time is when past technologies converge and become the foundation for future growth and discovery.

One of these moments began 60 years ago when Ivan Sutherland attended the Massachusetts Institute of Technology (MIT) and began researching human-computer interaction, which became the basis of his doctoral degree.

He designed and created computer software called, Sketchpad.

By 1963, Sutherland had completed his MIT thesis titled “Sketchpad, A Man-Machine Graphical Communication System.”

It has been acknowledged that Sketchpad strongly influenced the course of human-computer interaction using graphical interfaces, vector graphics, object-oriented programming, and computer-aided design (CAD).

Sutherland operated his Sketchpad software program using MIT’s Lincoln TX-2, a transistor-based computer constructed in 1956 at MIT’s Lincoln Laboratory in Lexington, MA.

I watched a 1963 MIT video demonstration of the graphical language Sketchpad.

A person seated at a TX-2 computer console demonstrated Sketchpad using a light pen (think stylus) on the round display screen.

The light pen is an input device in the form of a light-sensitive wand that allows the user to draw, point to, and activate any specific dots or objects on the computer display screen.

It is similar to using a finger on a touch screen, but a light pen has greater positional accuracy.

The 1963 video describes how in the past, problem-solving required a person to understand what the problem was and the steps needed to solve it, detailing the problem using punch cards and typewriting commands into the computer, which was used as a “very elaborate calculating machine.”

Sketchpad makes the computer work more as a human assistant, in which it seemingly has more intelligence — although it does not. The computer’s intelligence is derived from the Sketchpad software, making it more tolerant and flexible for error correction.

Next, a demonstration of the TX-2 computer using Sketchpad was presented at MIT Lincoln Laboratory by Timothy Johnson of MIT’s Department of Mechanical Engineering.

Johnson was seated at the computing console. He described the various input/output devices, magnetic tape storage media, toggle switches, and the round display screen he called a “scope” (oscilloscope).

He began the demonstration of Sketchpad using an electronic light pen to draw on the glass surface of the computer screen.

Using the light pen, he began by drawing two-dimensional straight lines and circles starting and stopping from specific positions on the screen, which the computer geographically locates and remembers.

The computer understands and remembers the geometrical radius angles of the drawings.

Johnson explained how the computer could execute a constraint command to satisfy any anomalies in a drawing, such as if two lines needed to be joined.

He also loaded a previously created drawing onto the screen from the computer memory and overlaid it with an existing drawing diagram.

Johnson said Sutherland expanded the Sketchpad program so it could draw in three dimensions.

This program was accessed from the magnetic tape and loaded into the computer.

Next, the screen displayed a single three-dimensional box in four separate views with one marked T (top view), F (front view), S (side view), and one marked F and S.

The drawings were seen on the screen (simulating how they would appear on paper), as would a mechanical drawing, with a movable F/S box diagram for perspective.

Johnson then began drawing a simple house schematic on the screen using lines with the light pen.

Then, he displayed previously created Sketchpad drawings stored in the computer’s memory of three-dimensional solid objects such as various-sized wood shapes and windows for home construction a design engineer could use.

Besides designing structures, Johnson also demonstrated the creation of components used with electrical engineering diagrams on the computer screen.

The program could also zoom in and out on the graphics being displayed.

Ivan Sutherland’s Sketchpad is a computer-human interactive graphical algorithm program that laid the groundwork for today’s computer-aided design, object-oriented documentation, and 3D graphic visual computer engineering software.

With Sketchpad, a person could draw shapes on a computer screen for the first time.

Sutherland discovered the need to create new technical terms describing specific computer interactions using Sketchpad.

MIT’s TX-2 computer is impressive in its own right. Publicly introduced in 1958, it became known for its role in advancing artificial intelligence and human-computer interaction.

On March 22, 1994, Ivan Sutherland spoke during the Bay Area Computer History Perspectives lecture series held at Sun Microsystems in Mountain View, CA.

In 1963, Sutherland received his Doctor of Philosophy degree from MIT in Computer Science and Engineering.

In 1988, Ivan Sutherland received the Turing Award from the Association for Computing Machinery for the invention of Sketchpad.

He is a member of the National Academy of Engineering and the National Academy of Sciences.

In 2012 Sutherland was awarded the Kyoto Prize in Advanced Technology for “pioneering achievements in the development of computer graphics and interactive interfaces.”

Sketchpad has been described as one of the most influential computer programs ever written.

It was years ahead of its time and is credited as the foundation for today’s computing graphics, graphical user interface, and CAD programs.

Ivan Edward Sutherland, called the Father of Computer Graphics, was born in Hastings, NE, and turns 84 on May 16.


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