VGX makes CAD more flexible

March 2, 1998 Design News

INSIDE STORY EXCELLENCE IN DESIGN: THE YEAR'S BEST PRODUCT

VGX makes CAD more flexible

Product of the Year winner also enables 2-D/3-D integration

Christine M. Ferrara, New Products Editor

Sometimes, the destination is more important than the journey. That's the idea behind VGX^TM technology in I-DEAS Master Series 5 mechanical design automation software, voted by Design News readers as the Best Product of the Year.

VGX is an extension of SDRC's (Milford, OH) variational CAD technology. With VGX, the "journey" toward the design--its history--is much less restrictive than with other CAD technology, SDRC says.

"Traditional history-based modelers focus on the history of the design rather than design intent," says Dilesh Patel, director for design applications at SDRC. "With VGX, you can do what you want to the design when you want to do it in real time without worrying about the sequence."

VGX uses bidirectional constraints, as opposed to unidirectional ones. "If you have unidirectional constraints, it's like building a stack," Patel says. "You have to understand the stack when you take one of the pieces out. When you have bidirectional constraints, you can take a piece out from anywhere, then put a piece back in."

When engineers change constraints (perpendicularity, etc.) in history-based modeling, they have to roll back the history to the point when the constraint was created. When the design is rolled back, everything done after the specific point is no longer visible to the user. Making associations to geometry you can't see is difficult. With VGX technology, the user works directly on the model and creates associations without rolling back or having to consider how the model was constructed, Patel says.

"If the engineer is thinking about designing and the software forces him to think about command and modeling sequences, there's probably going to be a great loss of conceptual thinking," Patel adds.

VGX features a variational sketcher, variational equations, variational shape design, variational sweep, variational features, and variational assembly. The 3-D dynamic navigator user interface (UI) for VGX provides both drag-and-drop and point-and-click interaction. The drag-and-drop technology allows the user to focus directly on the desktop without the distraction of frequent command selection. For example, drag and drop enables a user to get perpendicular lines by drawing one, then another, then moving the end points of the second line until it snaps into a perpendicular position to the first line. A perpendicularity symbol becomes visible.

"The dynamic navigator suggests relationships without the user explicitly requesting them," Patel says. "It's trying to anticipate what the user is trying to do."

Final analysis. DH Brown Inc. did an analysis of VGX. Marc Halpern, director of research for engineering manufacturing and design technology for DH Brown, says VGX's main advantage is its flexibility.

"There's much more flexibility than with standard history-based modeling," says Halpern. "They're stretching the envelope on what can be done with making history-based parts flexible."

"With VGX, despite the presence of object history, the technology allows changes, providing both the benefits of object history and the B-rep modeler," Halpern adds.

VGX integrates 2-D and 3-D design under a single solver, yielding benefits that are impossible if they are under different solvers. With VGX, the single solver allows dimensions on 2-D sketches to be seen in 3-D, and have the drag-and-drop behavior of fully 3-D dimensions.

Another ease-of-use feature in VGX is the dynamic navigator user interface, says Patel. It features fewer icons than its predecessor, since the software is based on drag-and-drop technology. Fewer icons reduces the software learning curve, and lets engineers get to work more quickly, Patel says. "With every release, we're actually reducing the number of commands on the system and making it easier. The high productivity that this software allows comes from the fact that it's easy to pick up and understand."

However, the software's ease of use and comprehension does not undermine its power. "You don't have to trade off functionality and ease of use," says Patel.

Not only can engineers design parts with VGX-enhanced I-DEAS Master Series 5, they can take advantage of variational assembly of those parts as well into whole products. "We wanted variational assembly to be as natural as mating things together in real life," he says.

Patel says SDRC is trying to design products instead of parts. "Engineering relationships like parallelism, perpendicularity, and dimensions represent a natural way of doing design," he says. "The trick is to design parts in the product context from the beginning."

Because multiple people are designing the product together, the constraints must not only be able to be applied easily, but who owns them must be made clear, Patel adds. Clear constraint ownership preserves the team environment of design. "Collaboration means getting the right data to the right people at the right time, and with the right resource," he says.

"Probably half of our effort on variational assembly was tied to making it all work in that team environment," Patel adds.

VGX is a core I-DEAS technology and is used in 2-D and 3-D implementation by all customers. Ford Motor Co. uses the variational sweep extensively in digital prototyping of complete vehicles. Honda and Lexmark use VGX, and Siemens is using the software for both product and tool design.

Juergen Graeser, an engineer for administration and support for I-DEAS for Siemens, says VGX technology is a good improvement and is easier to use. Siemens has been using I-DEAS Master Series for more than five years.

"You can save a lot of time in the conception and process," Graeser says.

Long journey. VGX's development evolved from early work on development of the I-DEAS Master Series itself in the late 1980s. Jack Chung, senior development manager for the project, and his team had to first convince others of the potential of the technology.

Chung wanted to create a flexible design system that focused on ease of use and drag-and-drop technology. The team created VGX as a prototype in 3-D in 1995 and presented it to SDRC executives. With the blessing of top brass, Chung et al developed 3-D VGX and debuted it in I-DEAS Master Series 5 in May 1997.

Before the official debut, however, VGX had to undergo some vigorous beta testing. SDRC brings engineers from several companies into its facilities to test the software, rather than sending software to engineers and having them test it at home.

Pete Bayerele, senior designer at Lexmark, beta-tested VGX versions both 5 and 6. He says VGX technology is "the right way to go. You can make all the right sorts of associations."

"What's there is good, but there's obviously room for growth," he says of Master Series 5. Of Master Series 6, he says it's "awesome. It's very intuitive."

The company shipped version 6 of Master Series with extended VGX technology in February, which expands on version 5 by providing increased variational interaction, and an enhanced dragging scheme for dimensions. Variational sweep features constraints on rails and paths, automatic path extensions, and automatic participating surface extension. Master Series 6 also features a production capability with variational assembly. "Master Series 6 marks our introduction of a production 3-D VGX capability with variational assembly," Patel says.

Patel says this software is very important to the company's mission statement. "This software features the ability to satisfy life-cycle needs," he says. "It eliminates physical prototypes, and gets products to market faster, which fits in with the core benefit of our software, 'Get there faster.'"

"We're seeing only the beginning of the coming revolution," says Chung.

Timeline for design

Late 1980s
The first discussions of VGX technology development begin.

June 1995
The design team begins work on the 3-D version of VGX.

November 1995
The VGX prototype is presented to management.

January 1996
Management gives the okay on the production of VGX technology.

January 1997
The team delivers the product to management.

May 1997
With the release of Master Series 5, VGX is introduced to the public.

Best New Products of the Year Contest

Last summer, we asked OEM suppliers to enter their most outstanding products in the Design News Best Products of the Year contest. Companies filled out a detailed entry form to nominate their significant products introduced since September 1996.

After an initial screening by Design News technical editors, the best entries were submitted to a panel of outside judges. The judges selected a top product in each of the seven categories: electrical/electronic; power transmission and motion control; fluid power; computer productivity tools; test, measurement, and control; fastening, joining, and assembly; and plastics, metals, and other materials.

Our December 1, 1997 issue featured descriptions of these top products, and Design News readers voted by fax for the single best product of the year. In addition, a drawing was held of all ballots received, with one of our readers winning a 35-inch Zenith color T