Software with what’s called an explicit-modeling approach lets device designers work directly with geometries on-the-fly without worrying about underlying constraints, parameters, and history trees that might otherwise hinder the creation of good-looking designs. Using this kind of CAD, manufacturers are exploiting current industrial design trends to create products that are head-and-shoulders above the competition, says Geoff Hedges, marketing director, PTC CoCreate (, Needham, Mass.

For example, says Hedges, the explicit modeler CoCreate is proving especially useful in the design of one-offs and highly customized products. “Small teams usually design medical products and they are often leveraging existing designs. The explicit-modeling approach makes it a snap for designers to change a housing’s ergonomic surface, for instance, without affecting the inside of the housing, as may well happen with a parametric modeler. Among other things, this capability is important because recent trends towards miniaturization mandate that the old cheap metal brackets to hold electrical components together are now integrated into housings. These kinds of complex designs usually take many iterations.”

Creating aesthetic surfaces, and more
A medical company in Germany leverages the software in the design of complex instruments for monitoring patients in intensive care. “Customers nowadays — both patients and hospitals — want medical goods to look stylish and appealing; that is, more like consumer items,” says Hedges. “The company uses CoCreate’s surface-analysis capabilities such as Gaussian and Zebra studies to see how light will reflect off of instruments. Light reflection is an important design element. For instance, look at certain plastic toys under light and you often see rip holes. You can’t feel the holes by rubbing your fingers over them, but they make the product look cheap. CoCreate’s analysis tools help designers create attractive free-flowing surfaces with continuous tangency.”

The company’s product development is similar to that of many medical manufacturers, says Hedges. “The electrical engineers first determine the volume the electronics requires. They pass this data into CoCreate and the industrial designer creates an outer shape around this volume. Mechanical-design components also help determine the shape. The designers create housings and electrical components in parallel, and the software makes it easy to shrink down a housing should the electronics get smaller. Users can mold shapes as if they are clay; that is, they can push and pull shapes without worrying whether or not models will regenerate. The software also lets users easily change the freeform outside surfaces.”

In addition, says Hedges, CoCreate’s ease-of-use helps facilitate attractive design. “Think of the program as similar to Microsoft Word in the sense that users can work on each other’s designs without necessarily having to know how a file was created,” he says. “For example, say you have a program such as Quark Express. You can easily edit your documents, but other users without the program would be hard put to figure out how the design was created. In contrast, everyone has Word, so users need not worry about what template was used to create a document — they just jump in and make changes. Explicit modelling is similar: Everyone is free to pick up designs and immediately go to work.”

Another trend, says Hedges: the mass customization of medical devices. “Again, the software’s ease-of-use facilitates these kinds of designs,“ he says. “For example, the German firm builds modular monitors that handle five inputs. Additional modules allow handling 40 inputs. One general housing therefore lets customers expand the capabilities of the device.

Helping start-ups
CoCreate also helped a U.S.-based start-up follow the trend of the modular consolidation of devices, says Hedges. Explicit modelling helped the firm come up with attractive, ergonomic designs for carts that give patients mobility by integrating multiple tubes, IV bags, pumps, oxygen equipment, and electronic monitors.

The firm needed prototypes in short time frames, says Hedges. “The software’s STL interface lets it easily prototype components for ergonomics and haptics as well as ensure parts will assemble easily,” he says. “Also, because CoCreate now lets users put textures on photorealistic parts in real-time, it serves the firm well for marketing as well as design. In addition, the software’s on-the-fly approach helps the company quickly develop products for varieties of patients.”

According to Hedges, the start-up typically spends 10 minutes showing new users the basics of CoCreate, and a few hours showing more-advanced operations. “Users are productive from day one, and fully ramped-up in only a week or two,” he says. “For example, one of the firm’s industrial designers needed to design an ergonomic handle for a medical device. He had never even used a 3D CAD package before. But after only two hours of instruction, the designer was able to produce 180 different handles of varying ergonomic shapes over the next two weeks.”