«With SysML v2, future developers will be using a modeling language that we were involved in creating.»

May 10, 2022 – Reading time: 5 minutes

Dr. Fabian Ziegler and Leonhard Mertz, two of our technology consultants at INVENSITY, have seized a unique opportunity for INVENSITY: they have participated in taking the SysML modeling language to the next level by contributing their practical knowledge to the review process of version v2. In this interview, we talk to them about how this came about and what significance SysML v2 has for the development of increasingly complex physical systems and systems engineering.

First of all, congratulations! You have been selected by the German Society for Systems Engineering (GfSE) to review the second version of the SysML modeling language. What is the importance of this for you?

Dr. Fabian Ziegler: My aspiration for my work is clear: I want to make a difference. And in this case, I was involved in creating something new with added value for technology development that, above all, will last. In the future, thousands of developers will be using a modeling language that Leonhard and I were involved in creating. Our experience allowed us to contribute a small part in making things better. For me, that’s something special. It makes me happy.

How did that happen exactly? And how did it come about that you were selected?

Dr. Fabian Ziegler: The idea was to put the development of the new version of SysML on a broader footing and, above all, to incorporate a practical perspective, i.e. the view of the users. To this end, various societies were asked to provide support, including the German Society for Systems Engineering.

Leonhard Mertz: The standardized modeling language SysML is administered in its various versions by the Object Management Group (OMG), a consortium that deals with the development of standards for vendor-independent, cross-system object-oriented programming. The OMG was approached with corresponding «requests for proposal» to present the need for changes to the previous standard. That resulted in a submission team in which up to 170 different companies participated, including software manufacturers, industry, universities – and GfSE. These participants were being consulted and got involved in the submission team to drive the development forward. Based on these «requests for proposal», a prototype implementation was realized, which was reviewed by the experts in review meetings.

Dr. Fabian Ziegler: Exactly. We were excited to be selected as two of these experts on behalf of GfSE to review SysML v2. To be very clear, this working group was put together with only experts in SysML.

Maybe for all our readers who do not know what Sys ML is – can you explain it briefly?

Leonhard Mertz: Sure. SysML stands for System Modeling Language. It is mainly used in the systems engineering field, usually when you want to visualize both the structure and the behavior of a physical system for everyone involved in the development such as project management, HW engineers, SW engineers. A single point of truth is created by using a graphical notation to summarize all the necessary information about the system in a single model.

Dr. Fabian Ziegler: As a result, the model looks like a giant tree diagram that you can zoom in and out. You can click through it like a website: With each click, you get a detailed view of a specific area of the project.

Leonhard Mertz: The main requirement is that the users know the syntax or the basic features of the SysML modeling language. Then they can communicate with each other via the model. The clear advantage is that it breaks down the complexity, and above all, you are not dependent on how people would usually articulate or write something down.

So, the idea is to make large development projects accessible to everyone and reduce complexity without sacrificing important information. Who are the users of such a model?

Leonhard Mertz: It could really be anyone involved in system development who knows the language, for example, project managers interested in viewing the progress. Or hardware and software developers who need to coordinate with each other and find the necessary technical depth in the model.

Dr. Fabian Ziegler: The users are primarily all developers, for example, software developers or system developers, or even system architects. Consequently, those who act on a somewhat higher level and, if necessary, represent interfaces from an area to be narrowed down.

Many have touted SysML v2 as a „quantum leap“ forward as a modeling language, what can you tell us about the improvements that adopters of v2 can expect compared to v1?

Dr. Fabian Ziegler: SysML v2 is much more line- and syntax-based. It unites graphical and language aspects and therefore is easier to automate and read out. At the same time, it is again closer to the procedure of classical software developments. It is more intuitive to understand. The greatest added value, however, really lies in the stricter formal syntax.

Leonhard Mertz: Another point is the textual notation. That means it will be easier for many developers to use the modeling language. Another advantage that SysML v2 brings is that there must be open interfaces to the model so that it can also be queried from other sides via open standards. For example, there will be a corresponding Java API so that you can query the model from any other tool. That will give you much better access to the models and information they contain. The last and essential point, why it can be called a quantum leap, is that it is a completely self and independent modeling language, SysML v1.x is a profile of UML 2 and is therefore subject to some restrictions in the implementation of physical systems, it therefore enjoys much more freedom in the implementation.

What kind of effort is required for development teams to implement SysML v2 into their product development process?

Dr. Fabian Ziegler: On the one hand, this depends very much on the complexity of the product development and, on the other hand, on where you already stand in relation to SysML adoption. The attitude of the users to the change in processes is essential for successful implementaiton. It can take anywhere between months or years until the motivation to learn and the mindset are in place. Even with the increased up-front effort, the efficiency gains are dramatic. You will be shocked how quickly results are seen. The communication between development groups is improved, which at the end of the day saves time and money during development.

Leonhard Mertz: It’s important to understand that there is not an all-or-nothing approach to implementation. That means I can also tailor the whole thing according to each project and team, and focus first on the problem areas that are currently important. Due to the scaling effects, SysML v2 offers an incredible number of possibilities to start small or tackle the essential core problems first. It offers a high level of accessibility.

Thank you for sharing your experiences with us! We can’t wait for SysML v2 to begin to be implemented in the real world!


  • Charles Walczynski

    Head of Communications

Interview Partners

  • Dr. Fabian Ziegler

    Industry Key Account Photonics & MedTec

  • Leonhard Mertz

    Senior Consultant

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