JT project groups

Task and Objective

JT (Jupiter Tessellation) is becoming a widely accepted neutral format for making 3D model data available in downstream processes and for exchanging this data with system suppliers – especially in the automotive industry. The JT Workflow Forum (JT WF), a joint project organized by the prostep ivip Association and the VDA, supports the further development and industrialization of the format by defining coordinated industry-wide use cases. It is also driving forward standardization of JT as a DIN/ISO standard.

The vendors represented in the JT Implementor Forum (JT IF) incorporate the use cases defined and prioritized by the JT WF in their software. The tasks they perform include developing CAx JT interfaces based on the current DIN SPEC 9138:2021 and STEP AP242 XML, implementing new functions based on user requirements, and coming to an agreement on common approaches to implementation. The objective is to increase user confidence in JT by providing interoperable software.

JT WF and JT IF are currently preparing a new benchmark with the aim of comparing and assessing from a neutral standpoint current JT interfaces in terms of the mapping of geometry, product and manufacturing information (PMI) and validation properties. Interaction between STEP AP242 XML and JT in the context of transferring assembly and kinematic information will also be examined. The last benchmark was performed in 2018. New versions of the standard and the tested software have been released in the meantime. The use cases involved have also been thoroughly revised.

Focus and concrete results

One of the milestones achieved in the past year was the presentation of prostep ivip's recommendation PSI-14-2:2022, which contains a comprehensive overview of the industrial use cases. Together with the publication of the DIN SPEC, this paves the way for ISO standardization of version 10.x of the JT standard. The ISO working group responsible for JT has launched the international voting process on the inclusion of the 3rd edition of ISO 14306 in the ISO work program. If the result of the vote is positive, actual work on the standard can begin during the current year. Publication as an international standard is planned for early 2024.

The project work focused on the industrialization of JT-based use cases in collaborative scenarios involving manufacturers and suppliers. These include, for example, multi-CAD collaboration, the exchange of semantic PMI and kinematics, and the exchange of metadata with STEP AP242 XML. Support for the 3rd edition of AP242 XML was successfully tested in two rounds of testing carried out by the JT IF.

Among other things, the tests showed significant progress in the transfer of semantic PMI, which is documented in the current version of the implementation guideline. Initial successes have also been achieved with regard to the exchange of kinematic data using AP242 XML. A fully functional mechanism was transferred between two different systems using the test model provided by the JT WF. As a result, the JT IF, together with the CAx IF, published an updated version of the recommended practices for AP242 XML product and assembly structure and for kinematics.

In the second half of 2022, preparations were made for the next benchmark, which should be brought to a close in the current year. The BM team developed the test cases, specified the order of the tests and assigned the test criteria to the test models on the basis of the test criteria defined in the JT WF. In addition, participating vendors installed all the authoring systems, viewing and testing tools, and the JT translators. A test run for the benchmark was carried out in close cooperation with the software vendors using the agreed settings and test models.

The results of the project work were presented at the prostep ivip Symposium and at the JT Day held at the end of last year and were published in the association's journal.

Organizational and technical challenges

The year 2022 presented a number of challenges. The coronavirus pandemic meant that we once again had to postpone the JT Day. Following the corona break, face-to-face meetings were also less popular, unless they were held in combination with an event like JT Day. Updating ISO 14306 for JT version 10.x remains a challenging undertaking, both politically and organizationally, and redefining semantic PMI is a complex task from a technical point of view.

One challenge in the context of creating the project plan for the benchmark was calculating the cost, which depends on the number of participants. We managed to develop a persuasive concept and demonstrated the added value of the benchmark, which resulted in a wide field of participants.

Planning for the current year 2023

The benchmark, which will come to a conclusion in the middle of the year, marks a natural end to the topics addressed to date in the JT IF. This means that the project group can focus on new key topics. These include, for example, the transfer of PMI to assemblies using AP242 XML with references to JT geometry elements and the embedding of material data in JT. The JT WF will specify the requisite use cases.

What the project coordinator says:

"Thanks to successful collaboration with the JT WF's topic-specific working groups, of which the kinematics and semantic PMI groups were particularly active, we were able to identify interesting new topics for end-to-end, JT-based processes. The same applies to cross-project collaboration between the JT IF and CAx IF. It was more intensive than ever last year, which made the successes achieved with regard to the topic kinematics possible in the first place."

What the project manager says:

"We brought new members on board last year and will continue add new participants to both the Workflow Forum and the Implementor Forum this year. This is a very encouraging development and an acknowledgment of the work we are doing. At the joint meeting and JT Day, it became clear just how important the exchange of information about JT, STEP AP242 and issues relating to digitalization is for the companies. Which is why we'd also like to see one of the major CAD vendors like Dassault Systems or PTC open themselves up to collaboration."

Project management

Rudolf Dotzauer, Continental
Bernd Watzal, Mercedes-Benz AG

Project coordination

Dr. Sven Kleiner
Tel.: +49 6151 7676 100
E-Mail: sven.kleiner(at)em.ag

Jochen Boy
Tel.: +49 6151 9287 382
E-Mail: jochen.boy(at)prostep.com


JT-WF participants:
:em engineering methods
Fraunhofer IPK
TU Darmstadt

JT-IF participants:
BETA CAE Systems
CT CoreTechnologie
Siemens Digital Industry Software
Tech Soft 3D
Theorem Solutions

JT-BM participants:
CT CoreTechnologie
Siemens Digital Industry Software
Theorem Solutions