More and more customers of Seats Inc. were switching to 3D. These customers, typically cab and truck manufacturers, wanted 3D models of Seats’ product—a seat—to import into the solid models of new cab designs. Here are three views of the same seat for trucks: (1) 2D drawing, (2) solids model, and (3) the actual seat. [Photo courtesy of Seats Inc.]
"It was 1975 when I first predicted that within five years, all mechanical engineers would be doing only 3D," laughs Joel Orr, vice president and chief visionary for Cyon Research Corp. (Bethesda, MD; www.cyonresearch.com). That didn't happen. True, fewer engineers and designers are still using 2D CAD, especially in large companies, such as automakers and Tier 1 suppliers. But what's holding back smaller manufacturers?
Myth: 3D CAD is too slow
Displaying a solid model on a computer screen used to take a frustratingly long time. No longer. Models pop up and refresh fast on today's inexpensive computers, what with 32- or 64-bit multi-core multiprocessors, gobs of RAM, and high-speed graphics cards (single or dual, and with gobs of RAM as well). This speediness applies to displaying huge 3D parametric assembly files, as well as recalculating history trees. Recent versions of CAD software add to these speed gains. For instance, some CAD packages prioritize what parts are displayed so that all aren't displayed in an assembly simultaneously. Some packages combine history-based parametrics and direct (explicit) geometry manipulation, switching between the two methods as needs dictate.
Myth: Lack of 3D CAD expertise
Engineering and design students used to take classes on 2D drawing methods and 2D CAD. Now the classes are about 3D solids modeling. "They don't have any real-world experience with board work and 2D layout," says Mike Saari, project engineer/CAD administrator for vehicle seat maker Seats Inc. (Reedsburg, WI; www.seatsinc.com), a user of Solid Edge from Siemens PLM Software (Milford, OH; www.siemens.com/solidedge). For these budding engineers and designers, says Orr, "2D is an anachronism. The major shift [from 2D to 3D CAD] will be generational."
Myth: 2D is all you need
A small number of design applications-1% to 2%, estimates Orr-still exist where 2D drawing simply makes more sense in terms of time and additional effort. For instance, designs that are perfectly, axially symmetric probably don't need to be designed in 3D. Nor do simple piping designs, sheet metal designs, and both electronic and circuit board design. (Up to a point. When electronic/circuit design becomes a packaging exercise, solids modeling becomes crucial. First, 3D CAD helps in determining whether a circuit will fit a given space. Second, finite element analysis (FEA) helps in determining a circuit's thermal properties. The FEA solids model can come from 3D CAD.) Traditional machine layout, says Bruce Boes, Siemens' vice president for global Velocity marketing, can still be more efficient with 2D designing than with 3D. But, says, Saari, "If you're in metal or plastic manufacturing, you'd be foolish not to go to 3D."
Outside of design engineering, certain corporate functions are still wedded to 2D: marketing brochures, product documentation, and parts catalogs, for example. The more these move to the web or to CD/DVD media, the more dynamic, interactive solids models will replace flat, unanimated 2D drawings. This becomes even more true with the increasing ease and popularity of photorealistic rendering.
Myth: 3D packages don't "do" 2D
At one time, 3D packages were not good at 2D work, such as dimensioning. That's no longer the case. More often than not, the 2D capabilities in today's 3D packages are broad and sophisticated, matching or exceeding the features in 2D packages of yesteryear. The irony is that these 2D features are not promoted as much as the 3D features in the 3D packages. In the real world, designers often lay down a bunch of 2D lines and then over time move those to 3D using hybrid 2D/3D CAD packages, says Boes. This hybrid 2D/3D design environment is common in the machinery industry, he points out.
Myth: 3D CAD is hard to learn
Tying one's shoelaces is hard to learn the first time it's tried. The same is true with solids modelers. Solids modeling software is continually getting easier to use and learn because of printed and on-line documentation and tutorials, on- and off-site classes, templates and embedded software intelligence, on-line forums, and wizards, prompts, and context help.
Myth: 3D CAD costs too much
Solids modelers do cost more than 2D CAD systems, considering that stunningly sophisticated and feature-packed 2D CAD systems can be downloaded off the Internet for practically free. The price of 3D software today is competitive to what 2D packages cost a few years ago. Today, a mid-range solids modeling system sells for $2,000 to $5,000. (High-end solids modeling systems, which can sell for $20,000 to $30,000 on up, have far more features than their mid-range counterparts.) And yet, 2D as a starting point is still popular with new users "in cost-sensitive countries," says Boes. "There's not nearly as much 2D in the U.S. on a percentage basis as what we're still seeing in India, China, Russia, and other countries like those."
There's another cost to consider. People competent in 3D CAD command higher salaries than those people who work solely in 2D. However, there are fewer of the latter these days.
Myth: Converting 2D drawings to 3D models has flaws
The major 3D CAD vendors have invested much development time improving the capability to convert 2D geometry to 3D. This was not for altruistic reasons: 3D CAD is a new and burgeoning revenue stream. Improving the conversion tools helps increase sales of 3D solids modelers. In the process, customers win. In the past, such conversions required drawings to be exact-no fudged dimensions, lines had to touch each other, and so on-or else the conversion would fail. ("If you had a year or two of bad users and their endpoints didn't touch . . ," muses Saari.) Conversion often depended on the precision of the 2D CAD system, the solids modeler, and the design itself. The resulting solids model too often required someone to manually check for and fix errors.
The overall quality of the source data (2D drawings) has improved over the years. So too has the quality and breadth of standardized workflows and 3D CAD migration tools. Together, these have made conversion and error-checking/correcting easier, if not always automatic or the resulting models perfect.
Reality: The competition
Two-dimensional drawing methods have been around for centuries. We went to the moon and back on the most complex transportation system ever-all documented in 2D drawings. So why go to 3D? The reason is simply because the companies making physical products in a competitive market will be surpassed by those companies using 3D to design new products. For a new company starting in China, for example, says Boes, "2D might be enough because they can throw enough bodies at the design problem." However, he warns, they might "hit the wall" at some point: the company might take on more work, or take on work with a degree of difficulty beyond what 2D can handle, or the competition down the street bought 3D CAD and got that much more efficient. Simply put, says Orr, "If you're not using 3D, it's going to cost you. It's going to cost you in innovation, in time-to-market, and in your ability to interest a young graduate to come work for you."
Reality: Fearing the unknown
Orr admits that he "did not comprehend the psycho-sociology of engineering design; that is, the internal and group factors related to the way people learned to design and communicate their design, and the way designs became products from groups working within organizations." Also, sad but true, people sometimes don't want to learn something new, or they don't particularly care to change, or it's hard for them to believe they can make money or more money by changing what they're doing. Or all of the above. Engineering managers, says Orr, have "tried the business case, and it hasn't worked. They need to consider how to address the social and psychological issues to help people over that hump [in migrating from 2D to 3D]." Adds Saari, "It's always a scary transition. Learning curve. Change. Fearing the unknown. But once you jump into it, you wonder how the heck you ever survived without it." Concludes Orr, "The benefits of 3D far outweigh the detriments of training, conversion, and costs."