SysML v2 is reshaping the way systems engineers approach modeling, offering a modernized syntax and semantics designed to improve precision, tool interoperability, and developer experience. Yet, as with SysML v1, the standard itself remains intentionally neutral: it defines a notation, not a methodology.
For teams working on the architecture of complex systems, whether in aerospace, transportation, defense, or IT, this neutrality can be a challenge. Large-scale engineering projects involve multiple disciplines, distributed teams, and evolving requirements. In such environments, it is critical to structure collaboration around a shared modeling methodology that defines clear rules for how to structure, interpret, and evolve the model.
At Obeo, we develop SysON, an open-source graphical modeling environment for SysML v2. Unlike many tools, SysON is designed from the ground up to be extensible, so organizations can adapt it to their specific processes and methodologies.
In this blog post, we share an early experiment that demonstrates how SysON can be extended to implement the Arcadia method, already developed and deployed by Thales on real-world industrial projects through the Capella modeling tool.
Why Methodology Matters in MBSE
SysML v2 improves how models are written and consumed, but it leaves many critical questions unanswered:
- How should the model be structured?
- How are different engineering levels (system, subsystem, software, hardware…) aligned?
- How are viewpoints defined and managed across specialties like safety, performance, or logistics?
Without methodological guidance, SysML v2 can quickly become inconsistent or difficult to maintain across large teams.
This is precisely what methodologies like Arcadia bring: a consistent, proven framework for collaborative modeling across disciplines, from early operational analysis to logical architecture and validation.
Extending SysON for Arcadia
Our prototype focuses on supporting two key Arcadia phases:
- Operational Analysis: What the users of the system need to accomplish
- Logical Architecture: How the system will work to fulfill expectations
We began by creating a SysML v2 library defining Arcadia-specific concepts using SysML v2 constructs:
package Arcadia {
part def OperationalEntity {
attribute isHuman = false;
}
use case def OperationalCapability;
part def OperationalInvolvement;
part def LogicalComponent;
action def LogicalFunction;
}
This library allows engineers to define Arcadia concepts directly in SysON as typed SysML v2 elements. These elements can be represented on a generic SysML v2 diagram such as the “General View”.
On this first diagram you can see a model with instantiated Operational Analysis concepts:
This second diagram shows instantiated Logical Architecture concepts:
However, relying solely on generic SysML v2 diagrams (e.g., "General View") is not ideal, such diagrams often lack the visual clarity and semantic focus needed to convey methodology-specific meaning. In particular, the semantic is primarily expressed through text. For example the kind of object (<<part>>, <<use case>>) and the extended type (:OperationalEntity, :OperationalCapability, etc).
To address this, we defined custom diagrams in SysON that align with Arcadia visual conventions:
- Operational Capability Diagrams use orange ellipses, human-shaped icons for
isHuman=trueentities, and nested boxes to represent entity hierarchies.
- Logical Architecture Diagrams show logical components (blue boxes), logical functions (green boxes), and their allocations and exchanges.
These two diagrams show exactly the same SysML v2 model elements, with two different graphical notations.
They were implemented with SysON’s low-code customization capabilities, based on the Sirius framework, making it easy to adapt the notation, layout, and editing palette to suit the needs of the methodology. Users can now, for instance:
- Add a human
Actorto anOperational Capabilityin one click, initializing the necessary attributes and type definitions behind the scenes.
- Create a
Logical Functiondirectly from aLogical Component, triggering the automatic creation of the appropriate typed SysML v2 elements.
It’s important to note that what we present here is a prototype, not a full implementation of the Arcadia method. The extensions we introduced in SysON are meant to illustrate what is technically possible when adapting the tool to support a specific MBSE methodology.
The modeling concepts we selected and the visual representations we designed are examples, not a definitive or exhaustive mapping of Arcadia into SysML v2. If we were to develop a complete, production-grade implementation of Arcadia on top of SysON, we would likely make different design choices, based on deeper methodology coverage, user feedback, and integration needs.
Watch this video to see a demonstration of this prototype:
Beyond Diagrams: Methodology Support with SysON
While this prototype focused on extending the language and visual notation, a complete methodology implementation would also include:
- Modeling assistants to accelerate diagram creation;
- Validation rules to enforce modeling conventions;
- Transformations and generators to produce reports, simulations, or downstream artifacts.
For a look at these possibilities, we recommend reading this blog post by Mélanie Bats, which presents advanced extensions in SysON.
Nevertheless, this prototype demonstrates a concrete and functional approach to aligning SysML v2 with the principles of a structured MBSE methodology such as Arcadia: typed elements and methodology-specific diagrams.
It also shows that, with the right extensions, the semantics of the methodology can be made explicit and understandable, rather than remaining hidden in textual definitions or naming conventions.
This is a key advantage of an adaptable platform like SysON: you’re not limited to the raw syntax of SysML v2, you can shape the modeling experience around your team’s way of thinking and working:
- Unify modeling practices across large teams;
- Improve models clarity and consistency through a simplified and meaningful graphical notation;
- Augment modeling productivity with custom palettes and views.
Interested in experimenting with your methodology?
If you are exploring SysML v2 adoption and need to tailor it to your organization’s way of working, SysON offers the flexibility you need.
Whether you use Arcadia or another MBSE approach, we’d be happy to help you to build an environment that reflects your modeling practices, with the power and modernity of SysML v2 and the flexibility of SysON.
About the specific topic of Arcadia over a SysML v2-compatible tooling ecosystem, more developments are underway. Stay tuned!
Contact us to learn more or discuss a custom implementation.