If your first CAD program was AutoCAD, you probably guessed wrong
The first CAD program most designers of the previous generation ever saw was AutoCAD. After its initial release in 1982 by a small band of developers from Marin County (North of San Francisco) created AutoCAD and swept up the CAD market. In 20 years, AutoCAD was established as the lingua franca of design.
The first release of AutoCAD was strictly 2D, but Autodesk added the third dimension in 1985 with AutoCAD 2.1. They must have thought they needed to since they were following on the heels of the 3D MCAD juggernaut, PTC. However, most designers were content to stay in their 2D comfort zone and continued to use CAD as just an electronic version of their drafting tables.
With millions of 2D CAD users able to run on the poor man’s computer (the IBM PC, instead of workstations on minicomputers required by MCAD programs), CAD entered the mainstream. The drafting table was relegated to museum-level obscurity. It was not until SolidWorks 95, 13 years after AutoCAD came onto the scene, that 3D CAD would enter the mainstream.
The first picture show
The first commercially available CAD system was the Picture System by Evans & Sutherland.
Let’s back up. In 1963, Ivan Sutherland of Evans & Sutherland had already created Sketchpad for his PhD dissertation at MIT. The Computer History Museum recognizes Sketchpad as the first interactive 3D CAD program. However, Sketchpad and the workstation it ran on (MIT’s experimental TX-2) would stay in the lab and not enter the market.
After Sutherland graduated from MIT, he teamed up with David Evans to form Evans & Sutherland. It is unclear how much Sketchpad code ended up in Evans & Sutherland’s CAD programs, the first of which was the LDS-1. Their first success came in 1968 with the Picture System for “interactive, dynamic 3-D line drawings” (pictured above).
MIT kept developing Sketchpad after Sutherland left the Lincoln Laboratory building, piling on the 3D features. In an old black and white newsreel, we see the bespectacled Timothy Johnson in a suit and tie earnestly conducting what may have been the first-ever CAD demo. He is seated at what appears to be a nuclear plant control room or perhaps battleship command. Such was the state-of-the-art in computers was at the time, with their dials and switches for inputs, an improvement over punch cards. Sketchpad added a most innovative light pen that seems to react to the screen, a glorified oscilloscope, more or less, with a 7-in. square screen on which lines flicker.
However, the lines were not ordinary lines, such as lines drawn on paper, and Sketchpad no ordinary sketchpad.
Johnson shows a simple house, like one a child would draw. He shows a front, top, and side view, like a drafter would draw. Then the magic happens. He makes the apex of a roof in one view, which immediately shows up in the other views. What may have looked like four independent drawings were not that at all but views of one 3D model. This was the first automatic view creation using a single source of truth, the 3D model.
As with every technological breakthrough, we must consider the impact on humanity. Wouldn’t automatic view creation put those paid to make them out of work?
They briefly pause to consider — and quickly move on. Technology then, as now, is relentless. Automatically and painlessly extracting orthographic views should have been seized upon as Sketchpad’s main selling point — had MIT been selling Sketchpad. The reporter could have filed his story right there had he realized the enormity of what he had witnessed. But we have to wait for it. Johnson has more to tell.
To prove it was truly 3D, not smoke and mirrors, the house, which has F, T, and S on its faces for front, top, and side views, is rotated about the vertical axis. Sure enough, the S is backward when the house is rotated 180°. There is no smoke and mirrors here. It is, however, a setup for what we are about to see next.
Lawrence Roberts of MIT shows us a wireframe of a simple part. “What if you were to stretch ‘fabric’ across the wires?” The part is rotated about the vertical axis, and the fabric hides the edges or parts of edges that would not be visible the perspective of the user.
The algorithm is taxing for the TX-2. The computer is overcome. It sputters and halts during the rotation. Remember, this is in the 1960s.
“The computer is doing a lot of calculations,” said Roberts.
Perhaps put off by halting display, the reporter does not seem as impressed as he should have been. The ability to remove lines on the screen that would be hidden from view in real life is nothing short of a technological marvel, if not a miracle, 50 years ahead of its time. Anyone seeing this who previously had to integrate a jumble of solid and dashed lines, which 2D orthographic views often are, into a 3D mental image and then into a hidden-line-removed isometric view, a Rubik’s Cube-level exercise, would have been floored.
The reporter asks how big the “paper” behind the “window” is. To his utter astonishment, it is 2 miles wide.
