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DesignWorld: 50 Years of CAD by Evan Yares

Veteran CAD industry leader, visionary and writer Evan Yares tells the story of SketchPad

Over at Design World there is an excellent article titled “50 Years of CAD” by Evan Yares. The article, which includes many excellent pictures, centers on Ivan Sutherland’s MIT PhD thesis “SketchPad” which Evan notes establishes not just the precedent for the first computer-aided design (CAD) software but also contributes pioneering work in the areas of the graphical user interfaces, non-procedural programming, and object-oriented programming.

Sutherland developed SketchPad on MIT Lincoln Labs’ TX-2 computer, at the time one of the biggest machines in the world. It had what today seems like a tiny amount of memory but then was huge: 306 kilobytes. The TX-2 had some advanced computing tech for the day, including an addressable 1024 x 1024 pixel display, support for a light pen for input and a pen plotter for output. It also had programmable buttons.

SketchPad was also ground-breaking because unlike early computer applications it was very interactive, supporting the ability to draw directly on the screen (think iPad) with a crosshair cursor.

SketchPad had the ability to draw lines, points, and arcs and utilized an array of 17 different types of “constraints” including vertical, horizontal, perpendicular, et cetera. And it supported rubber banding when drawing objects thus the objects like likes would stretch as you moved the cursor. This was very advanced stuff at the time.

01 - Ivan Sutherland on MIT Lincoln Labs TX-2 computer.

As Evans notes in his article, Sutherland went on to run ARPA (the predecessor of DARPA) and he would later co-found Evans and Sutherland a firm that many veteran CAD readers will recall developed hardware for 3D graphics and printer languages, among other related tech.

To read the full article–and we highly recommend it–go here.

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