Computer Assisted Design (Sketchpad)

“The cinema camera doesn’t make movies; it allows movies to be made. It’s the creative people who make it real to people.”

Ivan Sutherland

Computer Assisted Design (CAD) uses mathematics to do the geometry and calculations necessary to draw and design. CAD is faster and more accurate than hand drawing.

Sutherland’s “sketchpad” software, part of his doctoral thesis, was the first CAD program. Literally, decades ahead of its time, Sketchpad enabled a user to tell a computer how to draw, place, and move geometric shapes.

Explanation of Sketchpad

As a professor at various University’s Sutherland became a “Johnny Appleseed” of modern computer science. Eventually, he influenced and trained countless computer scientists who went on to make groundbreaking innovations.

A small number of notable Sutherland students include:

  • Alan Kay, inventor of object-oriented programming and the single-person modern computer (Xerox PARC).
  • Jim Clark (Silicon Graphics, Netscape).
  • John Warnock, inventor of PostScript, PDF, and co-inventor of spline fonts (Xerox PARC, Adobe).
  • Edwin Catmull, texture mapping and computer-animation pioneer (Pixar).
  • Bob Sproull, virtual reality.
  • Gordon Romney, 3D rendering.
  • Frank Crow, antialiasing.

No computer or business historian would argue that Sutherland is not one of, if not the most important, seminal scientists responsible for the modern computer.      

Eventually, in 1964, Sutherland stepped away from academia and replaced J.C.R. Licklider as head of DARPA, during the time that DARPA invented the internet.

Demonstration of Sketchpad

Interpress & PostScript

Interpress and PostScript enabled display technology, initially printers and eventually screens, to display output exactly as it would look between media. Printouts and screens, no matter the size, would look exactly the same. The technology is another from Xerox PARC.


Warnock left Evans & Sutherland, a computer graphics company founded by Ivan Sutherland, to join Xerox PARC. His was a page description language for laser printers. There was a prior page description language, “Press,” but it was inadequate.

At Xerox PARC, Warnock created Interpress to describe printed material.

Xerox executives repeatedly refused to meaningfully commit to commercializing the technology. Eventually, in 1982, Warnock and his boss Chuck Geschke, quit. They formed a new company, Adobe, to create a programming language for page descriptions, PostScript. They wrote the entire language from scratch.

Before PostScript, every printer had a proprietary means of communication. This made programming output especially difficult.

Jobs Adopts PostScript

Steve Jobs liked PostScript and invested $2.5 million for Adobe to finish the technology. He adopted it for use in Apple’s personal laser printer, the LaserWriter.

PostScript eventually caught on for printers and spawned a similar general-purpose page description language for screens. That technology is branded the Portable Document Format, or PDF, and remains widely in use today.

Eventually, Jobs used a modified version of PDF at Next Computer, the company he founded after Apple fired him. When Apple rehired him, Jobs incorporated screen PDF into the Macintosh. To this day, pieces and parts of PDF exist in both the Macintosh and iOS operating systems.

To gain wide adoption, Adobe eventually open-sourced PDF.

Today, Adobe does no substantive ongoing work on PostScript but remains a large company thanks to other innovations it fostered, especially software for graphic artists. Warnock eventually retired a multibillionaire but Xerox made no money from his work.