New Approaches to CAD 'Integration'

Article From: 6/1/2001 Automotive Design & Production, , Contributing Editor

These five windows in show (clockwise from left) a hierarchical tree of a brake rotor project and its various design cases; a view of the entire brake assembly; the brake rotor itself; the results of a Von Mises Stress analysis of the rotor performed within; and a spreadsheet to view and choose constraints, as well as view parameter names and specific parametric values.

five windows in

These five windows in show (clockwise from left) a hierarchical tree of a brake rotor project and its various design cases; a view of the entire brake assembly; the brake rotor itself; the results of a Von Mises Stress analysis of the rotor performed within; and a spreadsheet to view and choose constraints, as well as view parameter names and specific parametric values. The four sliders under Current Value are associated to specific rotor design features. Note the design goal here: limit the weight of the rotor while minimizing its cost. These displays and analyses are from within 3G.web.decisions and are based on a geometric model created in a CAD system somewhere out on the Internet. (Source: 3Ga Corporation)



Two capabilities are absolutely critical in today's wired, follow-the-sun design engineering world: collaboration and interoperability. These are not necessarily mutually exclusive capabilities. To a large extent, you need interoperability for collaboration to happen.

Two computer-aided design (CAD) products addressing these very issues are sufficiently new and different to warrant closer inspection. Both let designers collaborate across disparate CAD systems. Both also let "asynchronous collaboration" happen. One, EnCapta from Vistagy Inc. (Waltham, MA) is a plug-in that adds non-graphical information to a solid model. The other, 3G.web.decisions from 3Ga Corp. (Los Angeles, CA), merges two extremes in computer networking architecture to let users evaluate designs based on multiple parametric changes.

The plug-in approach
Engineers collect "pages and pages" of non-geometric information (e.g., costing, material, tooling, testing, and other data) in the process of creating product geometry, says Steven Luby, Vistagy's president and CEO. Little of this can be expressed or managed efficiently in a conventional CAD system. In fact, much of this information is unstructured and on various media: drawings, spreadsheets, email, handwritten notes, and more. Such information is hard to retrieve, analyze, and pass around to other decision makers.

Ideally, product data management (PDM) systems solve these problems by being a repository for that data. But, asks Luby rhetorically, "are you finding the product information?" The response is often "no," even moreso when you want to do something with the product data—other than design. Sure, the CAD model data is easily accessible, but what about all the other product definition data?

Many companies, continues Luby, write custom "wrappers" around their PDM systems to extract specific information for specific uses. For instance, a procurement manager may want to know about coatings, tolerances, and heat treatment specifications that are called out on a drawing—a drawing!—in the drafting part of the CAD model. More to the point, says Joel Orr, Chief Visionary for Cyon Research Corp. (Bethesda, MD), when you're following manufacturing instructions, you really want all the information and graphics to be together.

There has to be a better way to capture a complete product definition and distribute it throughout an enterprise. Luby says he's got that better way: Put all the data within the 3D model. Which, not surprisingly, Vistagy's EnCapta lets you do. This plug-in lets CAD designers and engineers add and associate non-graphical, non-geometric information to CAD geometry—and store it with the CAD geometry. EnCapta provides, continues Luby, "the context necessary for interpreting the rest of the CAD model." Adds Orr, "EnCapta basically adds functionality to CAD systems that naive users might have thought was already there."

EnCapta consists of three main components: customizable templates, an interactive user interface, and eXtensible Markup Language (XML) tools. Engineers use the templates to create EnCapta "objects," which are basically definitions for the type and structure of specialized information they wish to capture. Data such as design details, cost estimates, engineering change orders, material specs, and assembly instructions can all be EnCapta objects. These objects get linked to relevant CAD geometry. Individual EnCapta objects can reference multiple geometric features; conversely, multiple objects can reference a single geometric feature. The templates help ensure that the correct information is in fact recorded and stored. Better, the templates need only be defined once, regardless of underlying CAD system.

The user interface invites engineers to browse these EnCapta objects and display the associated geometry. Alternatively, engineers can click on a part in the CAD model to display the associated non-geometric data, now EnCapta data. Without leaving the CAD system, engineers can view, edit, sort, and search the design and manufacturing information associated with the geometry. Because these objects and the data within them are associative to the CAD model, it isn't necessary to re-enter data, such as a material's thickness, after making design revisions.

The XML tools act as a release valve for specific design data to leave EnCapta for other applications, and vice versa. This XML port can be set up as an automatic import/export; however, that winds up being yet one more link in the interoperability chain. Considering how software vendors are currently going ga-ga over XML—and for good reason—this extra link may be a "non-issue."

Also a non-issue is the size of the additional non-geometric data in the CAD model file. "If it's 5%, that would be a lot of information," says Luby.

For now, EnCapta comes up as a pull down menu in Pro/E, is accessed through function terminology in Catia, and it is a user function in Unigraphics. Often, users just assume they are using native CAD functionality.

The networking approach
3G.web.decisions from 3Ga mixes design collaboration with finite element analysis (FEA). It's also a bit more complex to explain. Orr's explanation is that 3Ga "links the parametric aspects of a CAD model to slider bars so that you're in a semi- or junior-simulation mode for exploring design alternatives." These alternatives are all the possible what-if results based on parameters you choose. The results are published to a database called the "Active Solution Space." Other design team members then use a browser-based viewer to explore the design alternatives in this solution space.

3G.web.decisions consists of three components—, 3G.access, and 3G.central—that combine two computer network architectures: peer-to-peer (P2P) and client/server. is a desktop application that imports CAD data from the CAD system (source). Then it lets you define and generate, as well as manipulate, design alternatives. Think of as a generic CAD tool to read CAD models from different vendors (currently SolidWorks and Solid Edge).

Behind the scenes, 3Ga creates a separate, neutral CAD model from the original CAD model, regardless of where you and the source CAD system are on the Internet. The neutral model is fully associative to the original model. It is also what you use to generate a range of alternatives based on what parameters you've selected. These alternatives are published (i.e., uploaded) to Active Solution Space. If the design is subsequently changed, such as a new hole is added, the whole process is repeated. That is, a new CAD model needs to be created at the source, which uses to generate a new set of alternatives, which are then published to Active Solution Space. displays two types of information. First, a spreadsheet shows constraints, design parameters, parameter values, and other analysis variables. Slider bars within the spreadsheet permits varying any parameter. This way, you can see different design alternatives and perform FEA such as static stress, heat transfer, and vibrational behaviors. Second, FEA results are displayed visually.

When a design is finally accepted from all the possible alternatives, things happen in reverse. drives the source CAD system to regenerate the design model. Incidentally, this new model is based on the approved, optimized set of design parameters back in Active Solution Space.

When interacting with the source CAD system, is a P2P application. When you're defining and generating design alternatives, is a standalone desktop application. And when you publish to or retrieve design alternatives from 3G.central, is a Web-enabled client/server application.

By the way, runs on Microsoft Windows NT 4.0 or Windows 2000 operating systems, unlike...

3G.access is a Java-based application that displays the pre-calculated design alternatives in the Active Solution Space. 3G.access has much of the same user interface as However, 3G.access is mostly a viewer that lets you fiddle with alternative design options; you can not use it to update the existing Active Solution Space.

This application is strictly a browser-based client application running on Microsoft Internet Explorer 5.0 or later. The server for 3G.access, and for that matter, is...

3G.central is a Web application server, based on Microsoft.NET technology, that stores project data, manages the flow of that data, and controls user access.

So what's this all do for you? Think about most of today's collaborative solutions. They let users access the native CAD geometry, redline where changes need to be made, and send emails alerting team members of potential problems. 3G.web.decisions, Yuri Kizimovich, president/CEO of 3Ga, very patiently explains, lets users evaluate multiple design configurations, see in real time the effect of potential engineering changes, and optimize design parameters over multiple criteria. Plus, the application makes live engineering content accessible from anywhere to anyone simply by firing up a Web browser and entering a URL to the design you wish to view and evaluate. In a sense, continues Kizimovich, the application creates and manages what-if scenarios for engineers in a "net-computing" environment involving multiple types of CAD system.

Something else: The 3Ga ability to generate a range of alternatives makes it different than standard FEA programs, which typically simulation one parametric value at a time. Another difference is that unlike most FEA programs, the 3Ga tech can work with fully featured CAD models (i.e., models that include holes, blends, and so on).

Hey, you know this is better than collecting all the product definition on paper and making FedEx part of the critical path in your design team's operations.

the EnCapta window










By clicking on the object labeled "inserts" in the hierarchical tree in the EnCapta window, the user can see a list of specifications for all the inserts used in this housing cap, including threaded inserts, sensors, and the one hose attachment. Or, still within the CAD system, the engineer can click on the manufacturing cost or procedures objects and see that information. As long as the information has been entered into EnCapta, the engineer can search for, sort, and edit any information associated with the product geometry. (Source: Vistagy, Inc.)