SysML v2: Introduction, Opportunities & Impact on Technologies

In September 2024, IBM unveiled its new product, IBM Rhapsody Systems Engineering. Rhapsody SE is a cloud-native web platform designed to help systems engineering teams develop smarter, more complex, and more competitive products. To do so, it relies on cutting-edge technologies, including the long-awaited SysML version 2.0. In this article, we wanted to delve into this new language, which is currently in its beta 2 version, but which already foreshadows a significant turning point for systems engineers and the way they conceptualize, design, and manage complex systems.

So, what's SysML v2? How is this different from the last version, and for what benefits?  Buckle up! We'll tell you all about the next generation of the Systems Modeling Language! 

TABLE OF CONTENTS

     1. General overview of SysML v2

     2. From SysML v1 to SysML v2

     3. The benefits of SysML v2

     4. SysML's  API and its new level of standardization

     5. SysML v2 and the Digital Thread

     6. SodiusWillert and SysML v2

General overview of SysML v2: refining SysML language concepts and promoting MBSE 

You may have noticed that the Object Management Group (OMG) wrote an update to  SysML’s  definition, following the introduction of its new version:  "SysML [2.0] is a general-purpose modeling language for modeling systems that intends to facilitate a model-based systems engineering (MBSE) approach to systems engineers [...]."   

Indeed, SysML v2 stands as the new generation of the Systems Modeling Language which has been designed to support and extend the adoption of MBSE's practices. SysML v2 also seeks to address the numerous challenges raised by increasingly complex systems and technological shifts by providing, among other things, enhanced modeling assistance to systems engineers.  

SysML v2 leans on the foundations of the original version of SysML while improving and reshaping the concepts of the notational language and syntax. Within this new version, SysML incorporates graphical and textual notations to add more precision and expressiveness to models. Regarding the syntax, it brings major improvements in variations, quantities, and units.  

SysML v2 leverages trade-off analysis, another powerful capability enabling the automated comparison of models. Last but not least, SysML v2 features a standard API, bringing interoperability to an upper level.   

From SysML v1 to SysML v2: the story behind the transition    

Over the years, SysML v1 has facilitated awareness and expansion of MBSE, and we've learned a lot from using SysML for MBSE. But it soon began to demonstrate a few limits. 

In fact, SysML presents restricted modeling capabilities and is often considered too imprecise. These constraints are definitely not an option for highly regulated industries such as automotive and A&D. And we know only too well how much these disciplines are driven by precision, consistency, harmony, and integration between language concepts. So, the new SysML enhancements seem to be even more compelling. 

The first version of SysML is based on the Unified Modeling Language (UML) metamodel. Although still very powerful in terms of standardization, visualization, communication, documentation, reusability, and tool support, the new version of SysML wanted to go even further.  

From now on, SysML v2 is built on the Kernel Modeling Language (KerML). According to the OMG, KerML is an application-independent modeling language with a formal semantics that's particularly well-suited to modeling existing or planned systems.  

Now let's take a closer look at the benefits of SysML V2, on which many experts and engineers are pinning their hopes. 

The benefits of SysML v2  

Improved precision with textual and graphical syntax  

SysML v2 aims to be less ambiguous than its predecessor. For that reason, it introduces both textual and graphical syntax which is intended to provide various and improved renderings of the same underlying model. For the recall, SysML v1 can only be expressed in standard graphical syntax. The new modeling language also introduces formal semantics, guaranteeing that the language structures have well-defined meanings.  

Textual and graphical syntax offer correlative ways of creating, modifying, and visualizing the model. More specifically, textual syntax proves to be a valuable aid for creating, visualizing, and modifying more precise elements of the system. As for graphic syntax, it makes a valuable contribution to the creation, visualization, and modification of "cross-cutting architectural views of the system".[1]. 

With its numerous improvements regarding expression language, SysML v2 ambitions to be easier to learn and use. Indeed, it intends to bring more precision and flexibility, as well as consistency in model creation. For example, textual notation allows you to automate the editing and creation of models. This capability significantly reduces the number of errors while boosting team productivity. For instance, graphical notation includes new and easier ways of describing relationships and elements.  This new notation system aims to be more intuitive and resolve the ongoing ambiguity problem.  

SysML v2 textual and graphical syntax for a simple vehicle model. Source and Credits: Object Management Group (OMG)

Enhanced Expressiveness through applications of usage patterns and variation point management

SysML v2 helps systems and software engineers add more expressiveness to their models. This new modeling language allows a more accurate and comprehensive way of representing complex systems and their behaviors, as we will see through these two following features: 

• SysML V2 enhances capabilities such as explicit concepts to support variability modeling, e.g variations and variants. The term variation refers to a way of identifying "any usage element such as an attribute part, port, action, or even a requirement as a point of variation". "Variants help to pinpoint a specific choice at a variation point". What's interesting here is that a standard SysML v2 constraint can be employed to constrain a selection at one point of variation [2].   
  
  
• SysML v2 also contributed to the uniform application of the definition and usage pattern. This feature aims to "enable the reuse of models through the creation of usage elements defined by a common definition element" [3]. Establishing a common definition element while tailoring each use to its own context drastically reduces the risk of confusion and modeling errors. 

Extensibility and new capabilities 

SysML v2 is already recognized for its future extension capabilities offering additional credentials for representing domain-specific concepts.  

By extension, we understand the use of “metadata that is analogous to defining a SysML v1 stereotype with stereotype properties and constraints”. The so-called constraint can now be expressed by using the SysML v2 expression language. [4]

Interoperability 

One of the key capabilities of SysML v2 is to integrate with other modeling languages, and modeling tools, facilitating communication and collaboration across disciplines. 

Regarding the ever-increasing complexity of systems and markets, it is now essential that SysML tooling interoperates with other tools. And to achieve this, a standard API featured in the v2 will play a preponderant role in the following months... 

This standard API and its “associated standard set of services to navigate, query, and update the model” enhance interoperability with a broader range of tools and software applications. In fact, it’s intended to enhance the way you operate the system model as part of a wider digital engineering environment. [5]

SysML's  API and its new level of standardization: a key advancement in systems engineering practices 

SysML's standard API (based on REST approach) is a major milestone in the standardization of systems modeling. This API is designed to make CRUD (Create, Read, Update, and Delete) operations easier, enabling developers to interact programmatically with SysMLV2 models. In more concrete terms, it means attempting to solve portability and data integrity problems and streamlining model interaction and resumption processes.  

One very important aspect of this API is the ability to support validation, analysis, and integration with other development tools. As a result, it delivers a pragmatic manner of ensuring completeness, consistency, and exactitude of models. 

In addition, the API allows automated documentation generation, guaranteeing that documents and information match up with changes to the system design. Finally, the API enhances collaboration and version control, facilitating more efficient team-based model development and maintenance. There's no doubt that this new API will open up a new, more flexible, and collaborative way of approaching complex systems management.  

When SysML v2 strengthens the implementation of Digital Thread 

SysML v2 significantly enhances the implementation of Digital Thread scenarios by providing a more robust, precise, and expressive framework for model-based systems engineering (MBSE).  It is specifically designed to handle today’s complex and highly evolving systems within a fully integrated digital approach where systems take a central position. 

Then, the improved usability makes this new version accessible to a broader range of experts throughout a project, from developers to systems engineers, and other larger groups of stakeholders. 

But it's the standard API coming along the v2 that really hits the mark. It fosters a seamless integration and data exchange between distinct tools and systems, which is essential for implementing a solid and continuous Digital Thread approach. 

SodiusWillert and SysML v2: towards new opportunities and better support for customers  

Those enticing improvements will lead to a completely new ecosystem where SodiusWillert technologies and expertise intend to play a key role. Indeed, our unique transformation, synching, and linking capabilities will enable us to fully support our customers in a smooth and automated transition from SysML v1 to SysML v2. 

As leaders of MBSE interoperability domains, we will be able to implement domain-specific data exchanges. Indeed, our teams plan to make our API Model transformation accessible to SysML v2, integrating SysML v2 in various digital sync and exchange scenarios. 

 We also intend to support highly advanced digital thread scenarios including SysML v2 artifacts. In the next few months and years, it would be also achievable to target new code generation and simulation frameworks. We've been involved in UML/SysML behavior execution for over twenty years now. We certainly intend to continue along this road, which will undoubtedly be full of challenges and fantastic opportunities. 

➡️ The possibilities are endless, and we look forward to seeing what's in store in the coming months! 

➡️ If you have any questions, please contact us.