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The existence of countless proprietary file formats and the exchange of 3D CAD data has been a significant problem since the beginning of 3D CAD modeling. CAD applications and methods using digital data are constantly changing, which predicates the need for a solution to share validated and accurately translated data. Thus the birth of STEP242.

Screen shot of a file validation page

Companies who are adopting model-based processes and tools within their organizations are using ISO 10303 STEP Application Protocols AP242 and AP239 for both exchanging data as well as maintaining data for archival and retrieval. Long Term Data Archival and Retrieval (LOTAR ) is an International project sponsored by multiple consortiums for the standardization of the archival and retrieval of digital product and technical data. This project is ISO compliant and works across multi-CAD environments enabling stake holders to share 3D data within a Model-Based Environment (MBE) or a digital enterprise. To ensure the preservation of design intent, validation properties that include geometric shape representation, assembly features, saved views, user-defined attributes, color, visibility, and Product & Manufacturing Information (PMI) 3D data need to be verified and validated for compliance. The culmination of these standards is allowing companies around the globe to manage interoperability with fewer challenges.

Government regulators are enforcing the need to retain digital documents indefinitely for legal, administrative and historical purposes. Dealing with government guidelines, the advent of MBE and the preservation of digital data necessitates the need for an approved process for managing this type of data. Many OEMs and suppliers are grappling with the notion of how to preserve electronic documents and information for 70+ years. Some of the issues they face include estimating the lifespan of storage materials, the potential obsolescence of file formats, upward and backward compatibility of applications and operating systems, and whether existing methods of reading data will be viable in the future.

AP242 is the replacement of standards AP203 and AP214. AP242 Ed.1 was released in 2014, and Edition 2 is well on its way to being released by the end of 2019. Although neutral formats are not the holy grail, the externalities to this format is the benefit of the consumption of downstream applications in the Computer Aided Engineering (CAE), Computer Aided Manufacturing (CAM) and Coordinate Measuring Systems (CM) domains. The provocative implementation of AP242 has been addressed in many studies at NIST.[1] CoreTechnologie (CT) can relieve the burden within companies and is often approached to make some sense of the countless requirements and standards. They are finding a proactive approach to this fast-changing industry as well as providing the necessary automation required within PLM applications.

The Airbus Story

One of the key driving forces behind the creation of LOTAR is the now famous case study of the Airbus 380 - when engineers in Germany and Spain were using a version of CATIA V4, and French and British offices had upgraded to CATIA V5. This meant the German teams could not add their design changes for electrical wiring back into the common three-dimensional digital mockup in France. Because of issues like these, engineering system managers are grabbing the technology as a solution from its indigenous prototypes STEP 214, and 203.

The mission of LOTAR is to develop a global standard based on archival and retrieval mechanisms for digital product and technical information. LOTAR will achieve this through the ongoing harmonization and standardization efforts of aerospace and defense affiliations and their common objectives. I have seen the adoption of other industries, as Daimler is using the AP242 to support its MBE collaboration - manufacturing information (PMI) integrated with models and embedding it within the JTOpen file format and 3D PDF.

STEP File Validation Options

Once the standards are written in a statement of work, they are then passed on to PDES, the US governing body, (here ) and the European governing body, ProStep, to define specific projects. The consortium members, PDES and the implementor forum (CAxIF) would then develop the requirements. As part of the goals for archival and retrieval, the resulting projects will seek to enable data exchange and interoperability mechanisms to ensure long term use of the digital product and technical information.[2]

Interactions with the Aerospace & Defense PLM Action Group aims at strengthening the communication of business requirements between users, implementors, standardization bodies, and regulatory authorities such as EASA and FAA. The Engineering Analysis and Simulation team has reached an agreement with NAFEMS to mutually benefit from expertise related to CAE and long-term archiving with AP209 Ed.2. With the near-term availability of AP242 Ed.2 as Draft International Standard, the Electric Harness group will support the launch of an implementor forum in this domain, as part of the CAx-IF, based on pilot projects conducted to support the development of the data model. As stated by Simon Frechette at NIST, “Each company’s modeling practice will draw that distinction differently. For example, export control limitations could be represented inside the MBD dataset, or as a BOM attribute, or both, depending on the company’s design practices.”

Industry Requirements

Many OEM’s have set guidelines on how to address a very common practice that takes place in today’s world of 3D CAD collaboration.

Each arrow in the above diagram could potentially be a conversion of one 3D CAD format to another. It is quite easy to see how information has the potential to be lost at any point during the process. This is partially due to different modeling kernels, which can compromise data integrity. LOTAR and other organizations have put forth recommendations on how to make this process less complex and ensure that a standards-based approach is taken during the conversion, storage, and validation of the format.

Methodology

CoreTechnologie has followed the LOTAR recommendation and has applied it to its suite of software – 3D_Evolution & 3D_Analyzer – to support all three major points: conversion, storage, and validation.

Validation

CT is the first interoperability company to develop the method of checking the validation properties of STEP AP242 files based on the recommended practices of LOTAR and its implementor forum PDES. File Validation is an important process for both sharing and storing data for future reference.

CT originally developed this functionality for Airbus, as Jean-Yves Delaunay is known to be a subject matter expert at Airbus and has assisted in defining the requirements at LOTAR and has written numerous papers over the past ten years. Using STEP AP242 satisfies the strict regulating requirements facing aerospace and defense companies. Validation reports were also developed using the direct feedback and recommendations of Airbus whose main concern was to satisfy the regulatory requirements of its government. There are three reporting options available: HTML, CSV, & txt. The HTML format provides a graphical representation of the many validation checks available.

Archive/Storage

Governmental bodies around the globe are increasingly enforcing regulations for aerospace companies to retain digital documents indefinitely for legal, administrative or historical purposes for as long as the airplane(s) remains flying. ISO 10303 AP242 is at the basis of how the LOTAR organization recommends the format of the digital data be stored for the foreseeable future. A standards-based approach will ensure that future absorption of the data will be at the same level of openness for all. LOTAR is also aiding in the area of reducing the amount of storage space needed to house all of this information in server vaults by providing recommendations on how to compress the STEP file format using an algorithm that will be open for all implantations to use, as well as provide the new file extension to be clearly understood that the STEP file is compressed and will need to be uncompressed for use in the future system.

CoreTechnologie has implemented the ability to batch process the conversion of native file formats with its 3D_Evolution product in the STEP AP242 format, BO model XML, ISO 10303-21 and compressed files recommended by LOTAR. This would allow IT departments to store and archive the digital data for years to come in a standards-based method as well as save money when it comes to the amount of disk space that would be required, as in some cases file size reduction can be as much as 35%.

Conclusion

CoreTechnologie continues to look at its road map to understand standards in the context of ever-growing global market requirements. CT has taken the necessary steps to align its suite of products to meet three of the biggest challenges when it comes to meeting regulations set forth by governing bodies: conversion, validation, and archiving.

Interesting mandates are challenging software companies these days. Robert B. Reich stated it best in an issue of the Harvard Business Review, “If you feel as if government and OEM relationships are breathing down your neck, get used to it. For the foreseeable future, governments are going to take an especially keen interest in how you’re managing your business. Executives should look for tighter scrutiny than we have seen for decades and now, [get] accustomed to ducking behind corporate and government relations professionals. We will need to develop a new mindset and skill set that will allow them to partner with the government rather than fend it off.”

This article was written by David A. Selliman, Vice President, CT CoreTechnologie Inc. (Southfield, MI). For more information, visit here .

References:

  1. https://www.nist.gov/publications/portrait-iso-step-tolerancing-standard-enabler-smart-manufacturing-systems
  2. http://long-term-archiving-and-retrieval.org/lotar-workgroups/lotar-3d-cad-with-pmi.html
  3. http://www.lotar-international.org/why-lotar/mission-objectives-scope.html
  4. http://www.cax-if.org/documents/rec_prac_gvp_v31.pdf
  5. http://edocket.access.gpo.gov/cfr_2010/janqtr/pdf/14cfr21.137.pdf
  6. http://www.boeingsuppliers.com/supplier/DPD_Task_Guide.pdf