3/5/2004 | 8 MINUTE READ

Heavyweight Collaboration Through Lightweight JT

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The ability to visualize design data of various types across platforms is now possible through a file format named “JT.” What’s more, the file sizes are but a fraction of what’s ordinarily been the case. This could be a tremendous boost for those who are looking for more collaborative processes.


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One of the things that’s been missing in design in general and collaborative design in particular is the ability to sling design data around different CAD, CAM, CAE, PLM, and other applications. Even being able to just visualize that design data without having to buy the CAD application that created those data would be nice. That deficiency has now been addressed: The 3D design world now has access to a file format that makes collaborative design simple, cross-platform visualization a reality, and data integration possible across a slew of applications throughout the supply chain. The file format is JT, which can store directly renderable geometry, analytical geometry, geometric attributes, facet information, lighting models, texture maps, user metadata, hierarchical product structures, and product manufacturing information (PMI), geometric and functional dimension and tolerancing data, and attributes (such as color, layer, and font).


The JT file format came from a small company with a bunch of nifty visualization tools used in a variety of industries. (The company also had some fascinating applications. One was an educational CD for exploring the human body and its internal organs. Another, a 3D animated re-creation of the April 19, 1995, Oklahoma City bombing.) These tools were so intriguing that Unigraphics—now UGS PLM Solutions (Plano, TX)—bought Engineering Animation, Inc. (EAI) in September 2000. With that came EAI’s DirectModel (JT) file format. When the two companies merged, UGS took on the lightweight JT file format; EAI added the Parasolid kernel to the tessellated geometry data that JT initially contained.

JT is CAD-neutral; it is a common data format for sharing 3D designs and product visualizations. The format packs a lot of information in a (relatively) small file. JT is specifically for actively exchanging models and product data between applications. It is not a static format, like Adobe PDF, which is a cross-platform publishing standard.

The JT binary file contains four “compartments,” each independent of the other. You can populate one and leave the others blank. Explains Chris Kelley, vice president of marketing for UGS PLM Solutions, the first compartment, the initial JT file format, contains tessellated geometry data. This data is basically “surface information in the form of essential points in space and how those points relate to one another. This provides the small—‘lightweight’—representation of the geometry.” This compartment supports basic viewing and text-based markup. The second piece of the JT structure contains surface geometry. In future versions of JT, this compartment will fully define solid models. This geometry is based on Parasolid, the CAD kernel in all UGS products, as well as in SolidWorks from Dassault Systèmes, the CAD applications from Bentley Systems, and other CAD, CAE, and CAM products. The third compartment contains a set of attributes (metadata). “This is wide open,” explains Kelley. The compartment lets users pass along a database associated with the part or the geometry. While it’s possible to use only that compartment as a text-data transport mechanism, Kelley is not aware of anyone doing that. The last JT file compartment contains PMI. This is a special class of metadata to help companies use the JT files in manufacturing operations, such as creating manufacturing prints, performing inspections, and creating tooling and manufacturing setups using the 3D model itself.

JT files can be 75% to 90% smaller than the source file for CAD geometry. For example, an average CAD file of a simple component—not an assembly—can range from 10 MB to 20 MB; in JT, it’d be a megabyte or so. XML, which is growing by leaps and bounds, is another data transport technology. XML is “open” (maybe too open) and scalable, but XML doesn’t have the same “lightweightness”—compression—that JT has.

These characteristics of JT make sharing product data and dynamic images throughout the product lifecycle painless. Even internally, companies are “maintaining JT data as a reference point, as ‘master geometry’ throughout the product development process and even after as reference to point back to,” says Kelley.


In December 2003, JT Open (http://www.JTOpen.com) officially debuted. This forum gives members a “direct and strong voice in the future of both the JT technology and the business model surrounding JT Open,” says Kelley. Membership to JT Open is, well, open: end user corporations (such as companies with their own software development group), software vendors, interest groups, and academia all qualify.

Despite JT Open, the JT technology is still the intellectual property (IP) of UGS PLM Solutions, explains Kelley. “We’re not giving up any ownership rights to that, per se, as a result of [JT Open]. We’re not throwing it out onto the market. Nor are we turning over the IP rights of the JT format to an independent or an outside organization. It’s copyrighted in the U.S.; we have patent protection on it.” This is not a new strategy for UGS. The company took basically the same approach with Parasolid, licensing it and essentially creating a de facto standard on the Parasolid side for a precise geometry model. In fact, points out Kelley, UGS licenses Parasolid to its “fiercest competitors” and has no intention of revoking those licenses.

Given the sheer number of potential users, vendors, and applications benefiting from JT, the file format could easily become the de facto standard for visualization and collaboration. “We’re not creating an industry standard in the likeness of STEP or IGES,” Kelley politely points out. STEP and IGES are open, published formats that belong to various standards bodies responsible for those formats. With JT, “there is one ultimate owner of decisions and one party responsible for implementation—and that’s us.”

This product/standards model is not unique. Remember the aforementioned Adobe PDF? Again, JT and PDF solve very different data transfer problems; however, the analogy fits. PDF is ubiquitous, PDF readers (Adobe Acrobat) exist for all platforms, PDF files can be written from a variety of applications, and both plug-ins and applications to create and manipulate PDF files are readily available. But, concludes Kelley, “the IP and technology is owned and managed by one company—Adobe Systems.”

Prior to JT Open, UGS was licensing JT on a per-seat royalty basis. This was relatively expensive, compared to the approach JT Open is now taking: a flat fee. JT Open members can incorporate JT and sell it to other members royalty free (no added incremental cost). “JT Open is like a buying club,” explains Kelley. “Once you get in, you’re free to trade [JT technology] between members.” Fees to JT Open cover the related administrative costs for managing JT technology. (UGS makes money by creating a bigger market for JT.) The one-time membership fees are on a sliding scale based on the size of the member company ($4,500 to $90,000 for corporate members; $22,000 to $90,000 for vendor members). Add to this an annual maintenance fee.


PTC (Needham, MA), which sells Pro/Engineer, is a vendor member of JT Open. By using JT, explains Michael Rygol, PTC’s senior director of visualization product management, PTC is letting its customers interact with JT files coming from EDS users. “We will still develop our own file formats because we have technical and commercial advantages in maintaining the data in our own formats.”

Another vendor member is CIMx (Cincinnati, OH). Explains Rick Franzosa, vice president, sales and marketing, for CIMx, CIMx has a “lot of large customers who are also large EDS users” (the largest being GE Aircraft Engines). As CIMx manufacturing management applications expand to include shop floor activities and software systems, which is on the docket this year, the CIMx applications will need to “communicate effectively on the manufacturing side. JT Open would provide us with a conduit to the design information our users have.” Right now, CIMx has that conduit as “onesies,” Franzosa’s word for a one-off, customized applications developed by CIMx for each CIMx customer and application requiring data interoperability. The idea, he continues, “is to make that conduit institutionalized so we have only one way of deploying it regardless of the UGS or CIMx customer. In the case of a company our size, somebody has to have the big lever to make that happen.”

Last, General Motors is a corporate member of JT Open. GM’s involvement with JT started in 1998 when EAI was selected as “the foundation to [GM’s] common visualization strategy.” This common visualization format, sometimes called a “pipeline,” currently supports more than 25,000 seats globally. GM now has more than 3 million JT files, predominantly product designs. “For all of our released CAD models, we have an equivalent lightweight version in JT that can be shared outside the design organization,” says Diane Jurgens, global director, CAD, visualization and collaboration systems for General Motors. This approach lets third-party suppliers look at GM’s CAD models without needing the source CAD system. (Internally, GM only uses Unigraphics or Parasolid.)

Back in 2000, GM started using JT in its metal fabrication plants. Before then, machine operators went to a blueprint room for a paper drawing of what was being stamped. Now, operators can look at the JT equivalent downloaded to kiosks on the factory floor. Within a year, the metal fab reported saving between $12 million and $20 million. “That was one quick achievement,” says Jurgens. “That really propelled using JT within the company among non-traditional IT users who could take advantage of this very easy-to-use tool and format.”

JT’s lightweight and just-the-facts packing enabled GM engineers to see entire vehicles in a single session. This helped eliminate the need for physical prototypes, saving GM $70 million in the direct material costs of physical prototypes in the nine months of first using JT for this type of work. Moreover, adds Jurgens, by working with more complete data sets, the confidence levels in engineering and design went up. Concludes Jurgens, “We’ve tried to standardize on JT format through all our processes so that if we want to bring a new tool on board, and it can read and write a JT file, we’re ready to go.”


What to look for in open collaboration

  • Ease and flexibility working within your current IT infrastructure and development processes
  • Installation, client access, performance, peripherals
  • Project management integration
  • Change management
  • Full, open data access
  • Multi-CAD including CAE, electrical, and plant design
  • Complete data attributes, not just geometry
  • Extensive open application programming interface (API)
  • Web publishing
  • Robust applications
  • Viewing, measurement, compare, and mark-up
  • Digital mock-up
  • Digital prototyping
  • [Source: D.H. Brown Associates, Inc.]


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