Life Before The Invention of CAD Software

For centuries, until the 1970s, all engineering drawing was done manually by using pencil and pen on paper or other substrate (e.g., vellum, mylar). Since the advent of computer-aided design (CAD), engineering drawing has been done more and more in the electronic medium with each passing decade. Today most engineering drawing is done with CAD, but pencil and paper have not entirely disappeared.

Tamron’s drafting department in the late 1970s.

Some of the tools of manual drafting include pencils, pens and their ink, straightedges, T-squares, French curves, triangles, rulers, protractors, dividers, compasses, scales, erasers, and tacks or push pins. (Slide rules used to number among the supplies, too, but nowadays even manual drafting, when it occurs, benefits from a pocket calculator or its onscreen equivalent.) And of course the tools also include drawing boards (drafting boards) or tables.

Urban designers before AutoCad.
The major disadvantage of a paper-based design was that you could not change the drawing after it was committed to paper. This would mean that if changes were required to the design, the engineers would need to create the sketches all over again.
A drafting class in the early 1970s.

The basic drafting procedure is to place a piece of paper (or other material) on a smooth surface with right-angle corners and straight sides—typically a drawing board.

In addition, the drafter uses several technical drawing tools to draw curves and circles. Primary among these are the compasses, used for drawing simple arcs and circles, and the French curve, for drawing curves.

The basic drafting system requires an accurate table and constant attention to the positioning of the tools.

A sliding straightedge known as a T-square is then placed on one of the sides, allowing it to be slid across the side of the table, and over the surface of the paper.

Computer-aided Design

CAD, or computer-aided design and drafting (CADD), is technology for design and technical documentation, which replaces manual drafting with an automated process.

Engineering drawing of a machine tool part

The modern age of engineering drafting was ushered in back in 1963 when a man named Ivan Sutherland invented a little program called Sketchpad. This was the first graphically interfaced CAD program – if you can call it that – to allow users to create x-y plots.

General Motors Technical Center in Warren Michigan.

By no means were engineers of the day using this program on a daily basis or even at all, but it started what is now a booming computer-aided design industry all centered around engineering design.

Significant intellectual and financial investments were made in the 1960s into CAD programs by engineers at Boeing, Ford, Citroen, MIT, and GM. Likely evident by the companies involved, CAD emerged as a way to simplify automotive and aerospace designs.

Due to a significant, lack of processing power compared to today’s standards, early CAD design required large financial and engineering capabilities.

However, thanks to Moore’s Law and the rapid growth of electronics, CAD capabilities expanded steadily over the next half-century. Right in the middle of that growing advancement, the engineering world saw the foundation of Autodesk. At this time, it was the computer hardware available that was holding CAD programs back.

Despite the massive effort by the technical field in the early 1980s, it wasn’t until the late 1980s and early 1990s that CAD software became capable enough to be practical in engineering design.

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