What we do

The MBx Interoperability Forum (MBx-IF) is an industry-driven initiative with its ultimate goal to enable support for user requirements in STEP translators for applicable software applications across multiple domains.

This starts with the User Groups, who document common industry use cases and derive business requirements. These use cases cover the external collaboration between partners as well as the internal collaboration within a company. Based on the use cases, requirements for data exchange and processing applications are defined.

The Implementor Groups review these requirements and develop draft Recommended Practices, i.e., commonly agreed upon approaches on how to map the desired information. While the STEP standard was intended to be unambiguous, when implementors started developing software against it they ran into areas where the implementation path was unclear, or where data values were obscure. The Recommended Practices reconcile this by providing detailed guidelines and examples on how to populate information in the STEP data model. Should extensions to the STEP data model become necessary, these will be communicated as issues to ISO TC184 SC4 for resolution.

The participating vendors then implement the new capabilities in their respective development environments following the provided guidelines. The resulting files are exchanged and validated during the Implementor Group’s Test Rounds. The test results are discussed in detail within the team, and the conclusions are reviewed with the User Group to verify that the original intent has been fulfilled. Lessons learned from these tests are incorporated into updated Recommended Practices, which will be publicly released after broader testing confirmed that the defined approaches are stable.

Eventually the capabilities developed in the MBx-IF will be included in commercial software products offered by its members and thus can be applied in production use in industry.

How we work

The cadence of the Interoperability Forums is set by the Implementor Groups’ Test Rounds, which usually last six months. There is a transition phase when a test round ends, during which the applicable Recommended Practices and current test models will be updated to incorporate what was learned during the previous test rounds.

Before the next round starts, a Test Suite document is compiled which describes what functionality will be tested, which test models will be used, the applicable Recommended Practices, as well as what criteria will be used to evaluate the tests. The test models are usually provided in different native formats but with equivalent content, to support a wide range of systems.

At the Test Round Kick-Off meeting, the Test Suite is reviewed, and any open questions concerning the test models, Recommended Practices, or testing evaluation are discussed.

During the next phase, each participants creates the STEP Part 21 and/or Domain Model XML files based on the native models and the approaches described in the Test Suite document and submits them to the facilitators. Checks on syntax and structure will be performed to assure sufficient quality of the files before they will be distributed for further testing. In parallel, data is entered into the MBx-IF online test environment, CAESAR, describing the contents of the provided files.

The participants then download the distributed test files and import them into their respective target applications. After thorough evaluation, more data will be added to CAESAR, indicating which aspects of the tests have been successful and where there might have been issues.

Regular conference calls over the course of the test round help the participants to resolve issues even while testing is still going on, which is a key factor in speeding up STEP translator development.

At the end of the round of testing, a meeting is held of all participants where the results and issues are discussed. Sometimes, if an ambiguous part of the standard is encountered, agreements are reached on how to interpret it and documented in the respective Recommended Practices. In joint sessions with the User Groups, the scope for the next round of testing is determined, and the process starts anew.

Related Projects and Organizations

The MBx Interoperability Forum is not an isolated activity; it cooperates with various other bodies and projects supporting the STEP standard. This helps promote the standard, support a wider range of industries, secure the enhancement of the STEP data model based on user requirements, as well as enabling smooth integration with other standards.

  • LOTAR is an international consortium of Aerospace manufacturers, jointly facilitated by AIA, ASD-Stan, prostep ivip and PDES, Inc. The prime objective is the creation and deployment of the EN/NAS 9300 series of standards for long-term archiving and retrieval of digital data, based on standardized approaches and solutions.
  • ISO / TC184 / SC4 (Automation systems and integration / Industrial data) is the organization within ISO responsible for the development of the STEP standard. It manages standardization in the field of automation systems and their integration for design, sourcing, manufacturing, production and delivery, support, maintenance and disposal of products and their associated services.
  • The JT Implementor Forum is a joint project organized by prostep ivip and VDA, supporting the development and industrialization of the JT format in combination with STEP AP242 Domain Model XML, by implementing coordinated industry-wide use cases defined by the user community in the JT Workflow Forum.
  • The objective of AP242 Benchmarks is to provide a public status of STEP AP242 functionalities available for operational use, tested by industry and to identify limitations of the tested commercial STEP AP242 applications. These benchmarks are jointly organized by AFNeT and prostep ivip.

Hosting Organizations

The AFNeT non-profit association has operated for more than 30 years a multi-sectoral “Think Tank” articulated with a “Do Tank”, with digital transformation projects or standardization projects in many industries. These activities have led to the emergence of a network of recognized and highly skilled actors from manufacturing industry, IT, business and research companies.

Its members represent leading industrial companies, SMEs, French governmental agencies, software vendors, universities, and research organizations.

AFNeT have conducted voluntary and innovative actions in order to develop competitiveness and innovation in industry by setting up collaboration projects or programs in the industrial sectors (Aerospace & Defence, Automotive, Rail, Shipbuilding, Nuclear, Energy…) to enable the digital thread for the Extended enterprise processes like Product Lifecycle Management, Supply-Chain Management, Manufacturing, Maintenance & Operations, Integrated Logistics Support, Identification.

AFNeT promotes the development, testing and the usage of a set of coherent international standards for supporting these activities, especially in the PLM and the SCM domains.

PDES, Inc. is an international industry/government/academia consortium committed to accelerating the development and implementation of standards that enable enterprise integration and Product Lifecycle Management interoperability. Its members represent leading manufacturers, governmental agencies, software vendors, universities, and research organizations. PDES, Inc. supports the Digital Enterprise through the development and implementation of information standards to support Model-Based Definition, Model-Based Enterprise, Model-Based Manufacturing, and Model-Based Sustainment. Testing of implementations and data exchange using standards is an integral part of PDES, Inc.

The prostep ivip Association is an international sectored community comprised of leading manufacturers and suppliers in the manufacturing industry, IT vendors, and research and science institutes. The aim of prostep ivip is to find solutions for the challenges facing the manufacturing industry as a result of networked collaboration in a worldwide development network.

The prostep ivip association remains committed to developing new approaches to end-to-end process, system and data integration for its members and providing digital support for all the phases of the product creation process.

The association has set itself the task of:

  • providing optimal support for cross-enterprise and cross-domain communication and collaboration
  • making a significant contribution to optimizing the value-added chain in the product creation process,
  • driving the development of open, vendor-neutral PLM standards forward,
  • securing the participation of key global players, whose representatives are personally involved to a great extent,
  • and ensuring the interoperability and quality of software solutions for the product creation process through the development of standards

The headquarter of prostep ivip association is in Darmstadt, Germany, and was founded in October 1993 by 38 industrial companies and a number of system vendors as part of the German STEP initiative. Members of the prostep ivip association currently include almost 200 companies and organizations from 17 nations.


To support efficient collaboration within as well as between the various domains and groups under the MBx-IF umbrella, a common web-based infrastructure has been set up. Its main pillars are CAESAR, a web-based database for the Implementor Groups for test evaluation, results, and technical discussions; Redmine, an open-source project management tool for the User Groups to document and track their requirements; and Nextcloud for all teams to store and share their documents.


CAESAR (CAx-IF Evaluation, Statistics, And Results) is an online database which was originally developed by the CAx-IF to replace the previously used Excel spreadsheets, thus better supporting the distributed way of working. It has since been extended to support all domains within the MBx-IF. It provides a ‘construction kit’ so that new test cases can be set up easily by plugging together the applicable testing criteria. It provides Implementors with instant feedback on the data they enter. At the end of a test round, results are compiled, technical discussions are tracked, and management summaries are extracted for efficient reporting.


The CAx-IF User Group organizes its work based on the Scaled Agile Framework (SAFe). Capabilities, Features, and User Stories are documented using the open-source project management tool Redmine and shared with the Implementor Group during the joint workshops every three months. This regular communication between users and implementors is supported by a bi-directional integration between Redmine and CAESAR, relating user stories to test cases and technical discussions.


An installation of Nextcloud is used by all teams with in the MBx-IF to store, share, and jointly work on documents and test files. It provides private folders for each team as well as shared directories for common topics.