Basic Idea The JT Workflow Forum (JT-WF) is a joint project of the prostep ivip Association and VDA. Its mandate is to support the further development and industrialization of the JT format through the definition of industry-wide, coordinated use cases. In addition, it actively drives the standardization and normalization of JT as a DIN/ISO standard.
The vendors represented in the JT Implementor Forum (JT-IF) implement the use cases defined and prioritized by the JT-WF in their software. Their responsibilities include the development of CAx-JT interfaces based on the current DIN SPEC 91383:2024 and STEP AP242 XML, the implementation of new functionalities based on user requirements, and the alignment on common implementation approaches. The overarching goal is to strengthen user confidence in JT through the provision of interoperable software.
The JT Workflow Forum continues to actively drive standardization within ISO 14306 Ed3 and a new DIN standard derived from DIN SPEC 91383:2024 — the JT Industrial Application Package (JTIAP).
User Perspective In 2025, the JT-WF focused on the exchange of kinematics models using JT and STEP AP242 XML, as well as on the application and validation of manufacturing-relevant semantic information (Product & Manufacturing Information, PMI) in JT files.
The increasing interlinking of data across format and domain boundaries led to intensified exchange and collaboration with other project groups, including the MBx-IF and the DDP project group dedicated to the development of AutomationML.
The project group revised the Content Harmonization Guideline, which defines methods for how specific information should be represented in JT and STEP AP242. The updated version is publicly available on the prostep ivip Association website.
Version 8 of the Content Harmonization Guideline introduces a recommendation for unique entity identifiers (Moniker IDs) for body edges in the context of external links to JT elements, enabling consistent use of the External Element References (EER) introduced with STEP AP242 XML Ed. 4. In coordination with the JT-IF, standardized attributes for identifying the CAD source as well as the converter used — including tool name and version — were also recommended.
The group continued to accompany the standardization process for the JT format at ISO level and initiated the process of transitioning DIN SPEC 91383 (JTIAP) into a formal DIN standard.
A highlight of the year for the entire JT community was the 9th JT Day, which was held exceptionally in an online-only format under the title JT Day Express. Approximately 70 participants were welcomed by the two project leads Bernd Watzal and Thomas Ott. The program featured engaging presentations on day-to-day work with JT and the future of the standard, under the event motto "JT for the Digital Future."
2025 was a year of particular significance for the JT Implementor Forum (JT-IF). A central milestone was the publication of STEP AP242 Edition 4 in late summer, which introduced essential new functionalities. Of particular note is the support for External Element References, enabling references from AP242 XML files to individual elements within JT files — a critical foundation for kinematics and assembly PMI. In parallel, the JT-IF supported the comprehensive update of the implementation guidelines for AP242 Edition 4.
In the area of kinematics, the successful cooperation with the CAx-IF was continued. Following the full support of common joint types, the focus has now shifted to more complex mechanisms. Material data integration in accordance with VDA 231-300 emerged as a new topic. Initial tests for the transfer of material and surface properties were successful, with broader support and improved attribute representation anticipated in the coming year.
Progress was also made in the area of Product and Manufacturing Information (PMI): the transfer of PMI in assemblies was initiated. Various approaches — purely JT-based or in combination with AP242 — are currently being evaluated and incrementally implemented. Each of the two test rounds held during the year saw the participation of eleven systems, with over 160 JT files exchanged in total. With these results and numerous new topics on the agenda, the JT-IF looks back on an exceptionally successful year.
Together with DIN representatives, the JT-WF initiated the process of transitioning DIN SPEC 91383 into a new DIN standard. Following several preceding coordination rounds, the official application was submitted on February 28, setting the formal approval process in motion. On October 30, the DIN working group "JT Standardization for the Industry" convened for a kick-off meeting, with a first working session held on November 27 and further meetings planned, including one scheduled for mid-January 2026.
While Part 3 of ISO 14306 — covering JT version 9.5 — was published in June 2025, the release of Part 4, which relates to JT version 10.5, has unfortunately been delayed. However, the eight-week FDIS Ballot on the final draft of the standard commenced on November 24.
The international composition of the working group — with participants from Europe, Asia, and the United States — enriches the project with diverse perspectives. At the same time, this global setup requires particularly careful and forward-looking coordination of time slots for online meetings across working groups and sub-groups.
Travel restrictions, partly driven by the broader economic environment, continued to complicate in-person meetings. Against this backdrop, the JT Day was successfully held in the JT Day Express online format, receiving very positive feedback from all participants. While the direct exchange with vendors about their products was not possible in the same way as at in-person events, the new format generated valuable experience. In 2026, the JT Day will therefore return as an in-person event — and for the first time, it will be held jointly with the STEP AP242 Day at the same location and time, in order to leverage additional synergies to the fullest.
The work of the subgroups within the JT-WF will continue in 2026. For Content Harmonization, the search for new topics is still ongoing, and practical experience gained from applying the newly defined recommendations will be fed back into future revisions.
Both JT-WF and JT-IF will continue to focus in 2026 on the transfer of PMI in assemblies via AP242 XML and on references to JT geometry elements (External Element References, EER) — a concept that will also gain increasing relevance in the kinematics domain. The further development and consolidation of single-part PMI and kinematics — both including Validation Properties — remains on the agenda.
The publication of the third edition of the JT standard ISO 14306 is expected in the first quarter of 2026. The group's main focus in 2026 will be on advancing and finalizing the transition of DIN SPEC 91383:2024 into a new DIN standard.
From the JT-IF perspective, key priorities include the continuation of topics newly initiated in 2025 — material data and assembly PMI — along with further expansion of kinematics support, and a comprehensive update of all JT-IF implementation guidelines, covering extensions to Validation Properties and the implementation of Content Harmonization requirements.
A major milestone will be the Engineering Interoperability Day on October 1, 2026, near Frankfurt, which will bring together both the JT Day and the STEP AP242 Day under one roof, uniting the two communities for the first time.
The economically challenging situation facing many project members — both on the user and software vendor side — has had a tangible impact on project work, manifesting in travel restrictions and shifting priorities. Nevertheless, significant progress was achieved, delivering meaningful added value to all project members.
"For ODA, participation in the prostep ivip Association is a strategic advantage. The JT-IF and CAx-IF meetings provide valuable networking and insight into the requirements of major industry players. Furthermore, early access to upcoming changes in open standards ensures our solutions remain at the forefront of innovation for our members." — Neil Peterson, President, Open Design Alliance (ODA)
Bernd Watzal (Mercedes-Benz AG): "My three highlights in 2025: We had a well-prepared and smooth change of co-chair from Rudolf Dotzauer to Thomas Ott, which I am very grateful for! I am also pleased that the JT Day online event, which was born out of necessity, was so well received. In October, we had the kick-off meeting of the DIN AK 'JT Standardization for Industry', combined with the task of transferring DIN SPEC 91383 into a DIN standard. As Co-Chair, it is important to me that we continuously align our activities in the WF, IF and the subgroups with the needs of the industry. We did this successfully."
Thomas Ott (Aumovio): "As the new project lead in the JT-WF, I am impressed by the strength of collaboration within this community. It has been an exciting start. The results of this year demonstrate the enormous potential that lies in the cooperation between users and vendors. For 2026, I want to harness this momentum and, together with all stakeholders, continue to advance JT as a key technology for seamless, end-to-end digital processes."
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