turn on the light

Engineers had worked the same way for more than 500 years—until the events of 40 years ago shook things up.

By Jean Thilmany, Associate Editor

Whether you consider your computer your best friend or a necessary tool, your relationship is still quite young. During the past 40 years, computer technology has revolutionized the way engineers design.

Before computers, design methods had changed little since the Renaissance, 550 years ago, says one professor. And the flurry of upheavals won't be abating any time soon. Electronic technology has taken pen and paper from the hands of engineers, given them digital design tools, and pushed them toward a Star Trek future they can only speculate upon.

In the estimation of mechanical engineering professor Filippo Salustri, modern-day mechanical design principles can be traced to Filippo Brunelleschi, a Renaissance architect famed for designing the cupola for Santa Maria del Fiore in Florence in the 1420s. He invented a new method of design in the process, according to Salustri, an assistant professor of mechanical engineering at Ryerson University in Toronto.

"As near as I can fathom, the way he designed the dome is he went through the basic steps of doing some concept design and feasibility studies," Salustri said. "He selected a concept, eventually came up with a detailed drawing of the entire dome, and then he broke the dome design apart. He developed part drawings, sent those to random manufacturers, and told them all, 'Don't ask me what this is for; you don't need to know.' He was afraid less scrupulous people might try to beat him by putting up a similar dome on a building."

In building the cupola for Florence's Santa Maria del Fiore in the 1420s, Filippo Brunelleschi invented a new method of design.

The octagonal drum of Brunelleschi's dome is made up of eight separate shells. Brunelleschi left empty spaces inside each of them to lighten the massive concrete structure. The ribs are not intended to provide structural support. Rather, they connect the dome's inner and outer shells. Another notable feature is the external covering system, which consists of tiles specially designed for easy assembly and maintenance.

Because the manufacturers so respected Brunelleschi's architectural genius, they agreed with his unorthodox request and sent back to him the mysterious pieces he had ordered, never guessing how the parts could be made whole.

Brunelleschi's basic six-step design process consisted of analyzing design requirements, making a concept design, making a detailed design, planning the manufacturing process, manufacturing the parts, and assembling the parts.

This method may sound conventional to modern ears, but by Salustri's reckoning, "It's the first time this six-step process happened in history. And it wasn't done for technical reasons," he said. "So he eventually told people how he'd built the dome because it was such a great success."

According to Salustri, "The design process stayed this way until the 1970s. For 500 years, engineers carried out this six-step process, the same six steps."

In the 1970s, the notion of engineers working on product design in teams combining manufacturing and mechanical engineers took hold and by the 1980s many engineering firms wholeheartedly adopted this concept, called concurrent engineering. Now nearly all designers work in product development teams, Salustri maintains.

CAD Makes the Scene

The switch to concurrent engineering may have changed the way mechanical engineers do their work, and around that time, an even more important phenomenon shook up 500 years of proven design methods: the advent of computer-aided design.

Salustri said he remembers seeing a picture taken to commemorate the advent of this type of paperless design. The photo depicted men with crewcuts wearing horn-rimmed glasses and white lab coats who had just managed to draw a straight line on an oscilloscope.

"They were hopping up and down," Salustri said, "because they had successfully mimicked the drawing pad."

The earliest computer-aided design systems used a cathode ray tube, a light pen and an alphanumeric keyboard. The first systems were in use at General Motors and IBM.

Howard Crabb isn't sure if he's one of the men in that old photo, but it seems likely. Crabb was a pioneer in the CAD field, lo these 40 years ago. In 1964, he wrote a program for General Motors—where he worked at the time—that used a cathode ray tube, a light pen, and an alphanumeric keyboard. At the time, there were two such machines in the world, one at an IBM research facility, and the other, created by Crabb, at the GM Technical Center in Warren, Mich.

Now Crabb is president and chief executive officer at Interactive Computer Engineering, a consulting company in Grosse Pointe Woods, Mich.

"You used the light pen and created drawings from geometrical entities like a line tangent to two lines, a circle tangent to two circles, and you input the radius," Crabb explained. "You could create any mechanical engineering design you wanted."

After the drawing was complete, the engineer printed it, after a fashion. The early CAD system was linked to a drawing machine, which replicated the design via a diamond stylus that scraped a Mylar coating off the surface of paper. That drawing was taken directly to the manufacturing plant and inserted into a shadow-box-style machine that cast the design on a wall. Shop floor employees would literally hold their molds against the drawing on the wall to ensure that they fell within proper tolerances, Crabb said.

Today, CAD can be used to create photo-realistic renderings.

That first CAD application significantly slashed design time at GM. A part that took a talented and experienced draftsman 50 hours to draw could now take an engineer 12 minutes to render, working with the cathode ray tube and the light pen, Crabb said. Already the difference between manual and machine design was becoming clear.

Among its other virtues, machine design was easier on the eyes and did away with the need for pen-and-paper calculations.

"All calculations that were done manually had to be done to four significant digits and a decimal point," Crabb said. "Then the engineer took a diamond-tip pencil and etched out the design. The engineer had to do all the calculations. You couldn't make a mistake because the design was going right to manufacturing. Working like that resulted in tremendous eye strain."

Time on the Board

Marian Bozdoc agrees with the eyestrain assessment. After years as an itinerant mechanical engineer in Romania, Germany, and finally New Zealand, he now operates a CAD contracting business, MB Solutions, in Auckland. Studying the history of CAD is a hobby for Bozdoc, who plans to write a book on the subject one day.

Bozdoc put in his time in front of a manual drawing board, so he remembers how engineers did their jobs without computers and even before oscilloscopes. After completing his design, Bozdoc sent it off to the moldmaker who—much as in Brunelleschi's day—created the mold by following Bozdoc's drawings. Then the moldmaker sent his mold off to the toolmaker, who machined the necessary tools from metal, again using the drawings as reference. The shop-floor employees then used that mold and those tools to make the part.

"Minor changes meant erasing and redrawing, while major changes during any stage of the process meant recreating the drawing from scratch," Bozdoc said. "And accuracy was the only way to ensure standards were maintained during the whole design process."

The future of design software resides in the science-fiction sounding realm of holedeck technologies—the capability for engineers to surround themselves within a virtual image and 3-D models (bottom).

Though the introduction of technology to the process made it easier to create an accurate drawing, Bozdoc thinks the technology's advent really changed actual engineering design very little. A CAD system, after all, is just another form of the pencil, he said.

Real design starts within the human head, Bozdoc said, and engineers still use pen and paper to jot designs during early concept, he added.
But early jottings aside, widespread use of CAD technology has changed a number of things about the product development process. The number of people who work together on a project can be reduced, because CAD streamlines design, Bozdoc said. Now, engineers analyze while they design, which ensures that the part won't have to be significantly re-engineered after the first prototype has been built. Also, engineers can send a design back and forth digitally, communicating while they design. This also speeds the process.

With CAD, engineers can be more adventurous with their designs, Bozdoc maintains. The tool allows engineers to try many different design iterations before they commit to one.

Forty Years of Change

Recent college graduates can be forgiven for assuming that their computers have always hummed along the way they do, and the CAD systems they use will continue to be improved once or twice a year. But Crabb remembers well the early years of CAD, which, to a 30-year-old engineer, no doubt resemble the dark ages of computer design.

After installing the cutting-edge cathode ray system at GM, Crabb moved to Ford Motor Co. in 1966. There, he helped put together a CAD users group. Around that time, the automaker also adopted finite element analysis software named Structural Analysis by Digital Simulation of Analog Methods, which had only recently been developed by MacNeal Schwendler, now MSC.Software Corp. of Los Angeles. The software has now evolved into MSC.Nastran.

The carmaker's technologists were still developing a comprehensive CAD system for Ford. There was no interface between analysis and design. Crabb also formed a kinematics group at Ford to run riding, handling, and other analysis problems on a computer.

"Everything was done with hand calculations prior to this," he said.
Then came what he called a nurturing period. Until the early 1980s, companies that used CAD were caught up in training engineers to operate the technology and in adjusting their own culture to fit CAD into everyday use. But the CAD culture was set to change again when two technological advances again revolutionized the way engineers design.

"One big improvement was a little something called the workstation; the other was the network," Crabb said. He installed Ford's first commercial Ethernet network around that time.

"It was only 10 million bits per second, but that sucker hummed," he said. "I put together a network with about 10 or 12 workstations attached. They were extremely expensive, about $50,000 each in 1984 dollars.

"That's big money," Crabb added. "But they cut design time so much they were actually a tremendous savings."

As the hardware and software became more powerful, ran faster, and included more memory, engineers used computers to attack different types of problems. CAD technology helped engineers think and design in three dimensions on a daily basis. As far back as 1966, Crabb and his colleagues realized that, using Boolean operations, they could program a computer to display a complete 3-D object. Finding the money for such a project was impossible, however.

"Mathematically, we knew it could be done," he said. "But we knew the machine we could build to do it would cost $18 million in 1965 money."

Now, 40 years later, 3-D display is so commonplace that children are learning to design on computers.

Computer systems are now used to design piping and other industrial systems.

As workstation computers became even more powerful in the 1990s, technology vendors coupled analysis capabilities with their CAD packages. Although analysts still ran computational fluid dynamics programs on supercomputers, they routinely used workstations for finite element analysis, which allows engineers to analyze as they design. The speed of Ethernet networks also continues to increase exponentially each year.

Today, Crabb calls the network the backbone of computing and of engineering design. Without networked technology, today's engineering firms would be lost, he said. The network allows designs to be passed back and forth quickly for discussion and approval, and it allows engineers working in varied, geographically dispersed locations to communicate as readily as if they worked in the same building. This certainly beats the old days, when engineers carefully shipped blueprints rolled in tubes between offices.

"Now an engineer can do two or three design iterations in a day, whereas it used to take him a week just to do one," Crabb said. "In one week, he can now finish the design. That's very significant. A lot of people say the most important feature in today's engineering technology is the ability to transmit it quickly between engineers. I think even more important is the reduced amount of time it takes to finish a design today."

Tomorrow and Beyond

Crabb predicts the computer network will further revolutionize the way engineers share information. Within the next few years, he said, engineers will witness more technological changes than their counterparts saw throughout the entire last century.

Improved network throughput speeds, coupled with increased power and memory of CAD systems, will allow future engineers to design an entire product as a system rather than as separate pieces.

CAD will change, too, Crabb predicts. By 2010 at the latest, the inclusion of virtual reality technology within engineering software will allow engineers to see exactly how their designs will look as products.

The next step will be the holodeck. Engineers will be able to enter a room in which lasers and computers generate 3-D designs around them. This would allow an engineer to walk around the design, as today an engineer can walk around a car as it's being built.

"By 2025, Star Trek will be here," Crabb said.

For his part, Salustri predicts that product development practices will change across North America. He sees concurrent engineering practices advancing further, as companies closely link industrial designers and mechanical engineers early in the product design cycle. The result will be more innovative product design, he said.

Today's product development process will likely be archaic, perhaps even quaint, to engineers of the not-too-distant future. From a Renaissance architect to the invention of a cathode ray tube to whatever the future holds, if technology is a one-way street, one thing is certain: Engineers will never return to pen and paper production. Other than that, who knows?



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