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A Step Up PUBLIC ACCESS

A Neutral File Format Brings More Information into Play

[+] Author Notes

Bryan R. Fischer is principal of MBD360 LLC, Sherwood, Ore. which offers training and consulting in 3-D model-based technologies.

Mechanical Engineering 137(03), 42-45 (Mar 01, 2015) (4 pages) Paper No: ME-15-MAR-3; doi: 10.1115/1.2015-Mar-3

This article presents work done by International Organization for Standardization in providing useful information. The International Organization for Standardization has released a new standard for the exchange of product-model data, ISO 10303-242, which is a new application protocol standard in the STEP family of standards. The standard significantly improves STEP’s capabilities, especially in providing useful information for an enterprise. STEP is commonly used in industry to share 3-D CAD model geometry with organizations using different CAD software with different proprietary data formats. The semantic information of the new standard is computer-interpretable; it can be used in semi-automated and automated systems and is intended to be used by software designed for tolerance analysis, inspection, and manufacturing. The CAx Implementor Forum is an essential part of STEP development. The CAx-IF works in parallel with the AP242 team to develop recommended practices for the implementation of AP242 in CAD and data translation software, to test the data models and best practices, and to provide critical feedback to the AP242 team.

THE INTERNATIONAL ORGANIZATION for Standardization has released a new standard for the exchange of product-model data, ISO 10303-242, which is a new application protocol standard in the STEP family of standards. The standard, published last December, significantly improves STEP’s capabilities, especially in providing useful information for an enterprise.

The new standard makes more data avaliable to more people throughout an enterprise.

Grahic Jump LocationThe new standard makes more data avaliable to more people throughout an enterprise.

STEP is commonly used in industry to share 3-D CAD model geometry with organizations using different CAD software with different proprietary data formats. Thus, STEP is commonly used to move data between CAD systems (CAD- to-CAD) in a neutral data format. More importantly, STEP is also used as the basis for downstream processes, such as inspection, manufacturing, and assembly. These uses are significantly improved by the release of the new standard.

The full title of this new STEP application protocol standard is ISO 10303—Industrial Automation Systems and Integration—Product Data Representation and Exchange—Part 242: Application Protocol: Managed Model-Based 3D Engineering. It’s often abbreviated to AP242.

From my perspective, the biggest benefit that AP242 offers to industry is the promise of neutral 3-D semantic data models of parts and their product and manufacturing information (PMI). So now, in addition to the geometry, all that PMI will be available in downstream processes.

AP242 offers the promise of true data interoperability in a neutral format. It’s the next step in the transformation of business from the old 2-D drawing world that started with the Industrial Revolution to the semantic 3-D data world where we’re heading. Semantic models of 3-D product definition data and the resulting increase in productivity are where the promise of computerization leads. It’s a natural progression.

Semantic means the data is correctly modeled, structured, and formatted in a predictable manner properly associated to the applicable 3-D geometric data.

Interactive, semantic 3-D datasets are superior to 2-D product definition data in many ways. The query and graphical response capabilities as well as the capability to rotate and zoom in 3-D systems are key reasons to move away from 2-D drawings.

Also, much more information can be conveyed in 3-D and the information is presented more naturally and is easier to understand. Static, 2-D media like drawings can’t provide the same interactivity and ability to group, filter, and drill down into data that 3-D systems can.

Standard Goals

The STEP AP242 standard lies at the convergence of many technological improvements. With the ubiquity of laptops, tablets, and other portable viewing tools, more of the workforce can and should have access to these interactive datasets. And with ever more powerful data management systems, datasets can be structured to encompass more of the product lifecycle and remain relevant longer.

A geometric tolerance is queried using the IDA-STEP GD&T editor. Selecting the profile of a surface tolerance causes the associated surface to highlight in response. “Query,” in this context, means to obtain information from the model, which includes geometry, product and manufacturing information, attribute data, metadata, and the like. Note that the related semantic PMI entities are also highlighted in the GD&T view list.

Grahic Jump LocationA geometric tolerance is queried using the IDA-STEP GD&T editor. Selecting the profile of a surface tolerance causes the associated surface to highlight in response. “Query,” in this context, means to obtain information from the model, which includes geometry, product and manufacturing information, attribute data, metadata, and the like. Note that the related semantic PMI entities are also highlighted in the GD&T view list.

The semantic information of the new standard is computer- interpretable and facilitates the automation of processes on the factory floor.

Grahic Jump LocationThe semantic information of the new standard is computer- interpretable and facilitates the automation of processes on the factory floor.

This is an exciting time to be working in 3-D product defi nition standardization and in industry.

AP242 combines the best aspects of AP203 Configuration Controlled 3-D Design of Mechanical Parts and Assemblies and AP214 Core Data for Automotive Mechanical Design Processes. AP242 was created as an alternative to updating AP203 and AP214, which have similar functionality.

“AP242 is the means for Industry to Protect its Investment in its Information Throughout the Life of its Products.”

Howard Mason Bae Systems

The main goals for AP242 were to include all the functionality of AP203 and AP214, develop a business object model to defi ne structured approaches for common uses, develop a semantic data model to represent product and manufacturing information, and more rigorously address external element references, composite parts, kinematics in assemblies, and tessellated data.

STEP AP242 was developed by an international team led by PDES Inc., an international consortium of industry, government, and university members that aims to accelerate the development and implementation of standards that have to do with product lifecycle management interoperability. The development team was also led by ProSTEP iViP of Darmstadt, Germany, an international association that helps develop standards to manage product data and create virtual products.

Representatives from original equipment makers and software vendors as well as standardization and subjectmatter experts also participated in the multiyear effort to bring STEP AP242 to fruition.

I participated in this project as a subject-matter expert with specific focus on dimensioning, tolerancing, geometric dimensioning and tolerancing, and on ASME Y14.41 and ISO 16792 digital product defi nition standards.

AP242 includes semantic data models for dimensioning and tolerancing and for geometric dimensioning and tolerancing as defi ned in ASME Y14.5 and ISO Geometrical Product Specification standards. These standards defi ne the meaning of product and manufacturing information.

These standards have existed for decades, initially developed in the era of 2-D drawings. Thus, much of their content applies to 2-D drawings and presenting information in a 2-D context.

But the semantic information of the new standard is computer-interpretable; it can be used in semi-automated and automated systems and is intended to be used by software designed for tolerance analysis, inspection, and manufacturing. This information is not intended to be used like the information shown on a 2-D drawing. It is supposed to be used or consumed by software. Thus, it is critical that the GD&T and other PMI is represented semantically and it is critical that the standards defining the PMI, such as ASME Y14.5 and ISO 1101, include robust definitions that support semantic data modeling. Much of the 2-D content in these standards needs to be updated to support semantic data modeling.

To remedy some of this shortcoming, AP242 also supports the ASME Y14.41 and ISO 16792 standards, which govern the structure and use of 3-D digital product definition data.

The National Institute of Standards and Technology sponsors and participates in much of the work done on STEP standards. To ensure we develop a useful, interoperable data standard, the proposed data models and methods must be rigorously tested and validated.

Another organization, the CAx Implementor Forum, is an essential part of STEP development. The CAx-IF works in parallel with the AP242 team to develop recommended practices for the implementation of AP242 in CAD and data translation software, to test the data models and best practices, and to provide critical feedback to the AP242 team.

The CAx-IF includes CAD, translation, validation, and STEP software developers, and STEP and other subject matter experts. CAx-IF tested prototype versions of AP242 through the standard’s development. The developers believe that most of the bugs have been worked out of CAD software and other software that supports AP242, which will expedite its industrial deployment.

Major CAD systems currently support STEP AP242 format, including Catia, Creo Parametric, NX, and others. AP242 tools and translators are available from Capvidia, CoreTechnologie, Datakit, ITI Transcendata, LKSoft, Theorem Solutions, and others.

Product data management software also supports AP242 and its business object model. For instance, Jotne EPM Technology’s express data manager allows users to automatically generate databases that comply with AP242. These databases can be used for quality assurance of AP242 data, as part of a PDM system, and for other uses.

Developers of the standard are enthusiastic about its possible application. One of those who contributed to the development process is Howard Mason, corporate information standards manager, at BAE Systems, the British defense and aerospace company. As Mason put it: “AP242 is the means for industry to protect its investment in its information throughout the life of its products, and forms part of an integrated set of standards that cover the product information requirements of the entire product lifecycle.”

Copyright © 2015 by ASME
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