Unigraphics Goes Interoperable

Automotive Manufacturing & Production, Oct, 2000 by Lawrence S. Gould

Interoperability is essentially the high-tech term for getting the right hand to know what the left hand is doing, and vice versa.

In CAD/CAE/CAM terms, interoperability is what makes "concurrent engineering" and "simultaneous engineering" now work the way many people once envisioned those team approaches would work. Better late than never. What's pushing interoperability to the fore these days is e-commerce, a term freely used as a concept, a way of (business) life, and a technology.

WEBIFIED INTEROPERABILITY.

Unigraphics Solutions' (UGS') parasolid is a kernel modeling technology used in about 225 applications throughout CAD, CAM, product data management, visualization, and beyond. To exchange data, these applications rely on IGES, PDES, direct translators, and XT, UGS' open format for storing MCAD data. XT is great if all you're exchanging is part shape data (geometry and topology). However, e-engineering and e-manufacturing require exchanging more than that on a regular basis, namely product structures, design intent, and process data (such as material properties and manufacturing process information).

Enter eXT, which can mean either "extended" or "enhanced" XT, explains Ken Sears, Managing Director for UGS. eXT, a new initiative from UGS, is an XML-based 3D MCAD interoperability standard. In short, UGS is wrapping XML around its Parasolid XT format. (XML merely acts as a mechanism for storing and transporting part data.) Consistent with the XML standard, you can associate additional attributes, classes, process data, and so on to the Parasolid models as required. Third-party vendors can also add XML element types to contain specific information. In fact, because eXT will be an open standard, any MCAD vendor can write applications that support it.

The eXT format allows multiple representations, or data formats, of a part. This lets users exchange the format most appropriate for their needs. The first release of eXT will support Parasolid XT, to store B-rep data, and facet representation, to store data for part visualization. Product and assembly information will be supported through instance graphs, views of specific configurations, and references to external files. Process information--that is, nongeometric information--will require a format for representing classes of process-specific information and instances of those classes.

The initial release of eXT will focus on exchanging geometry, topology, and product structure. Later releases will include engineering details and process data, and eventually features and knowledge-based rules. The complete v.1 eXT format should be available by now; v.2 should be available by the end of the year, around the time UGS releases Parasolid v.4.1. New versions of eXT will be released every six months or so until the format has everything people need.

KNOWLEDGABLE INTEROPERABILITY.

The next version of Unigraphics, available sometime soon (if not by now), will show the fruits of a collaboration announced last summer between UGS and Heide Corporation (Medfield, MA): Embedded in its core, UG v.17 will have Intent!, Heide's rules-based modeling language.

Intent! lets CAD/CAM users capture and reuse engineering design rules, and it provides a configuration system for selecting and assembling compatible parts. (Think knowledge capture here.) Users can define "smart parts" that can be assembled and configured in new ways-ways that are not pre-programmed--but that still conform to engineering, configuration, and geometric rules. Embedding intent! within UG lets the application display key geometric objects for generative applications, while maintaining associativity between the generative rules and the resulting model.

UG v.17 will move from the conventional design approach, what Chuck Grind-staff, UGS Vice President Products (R&D) and Operations, refers to as "the geometry leads the process," to a more natural engineering design process where "engineering leads the process." in the former approach, the design process involves creating geometry, adding "rules" (constraints), evaluating the design, then modifying that design. In the latter approach, the process involves capturing knowledge (rules), evaluating those against the criteria for the new design, and then creating geometry.

These two design approaches will be available through UG/Knowledge Fusion, one of many rules-based modules in UG v.17. Other modules in the UG knowledge series will be separate wizards for mold and die creation, welding, gear engineering, and casting.

Interoperability comes through another module, UG/Knowledge Pipeline, which basically integrates UG/Knowledge Fusion, and rules-based engineering, to external applications.

MICROSOFTIAN INTEROPERABILITY.

Unigraphics and Microsoft Corporation have announced DesignKNet (Design Knowledge Network), a set of tools to develop portals for multiple users to collaborate during the design process. DesignKNet lets users see design changes within UGS CAD/CAM/CAE software in real time.