SysMLSystems Modeling Language A graphical modeling language for systems engineering, based on UML, with block, activity, state machine and parametric diagrams. v2
SysML v2 projects: text and diagrams as one model.
Holarch supports SysML v2. Write the model in the SysML v2 textual notation, edit it in the standard views, and run requirements, verification, interfaces, budgets and frameworks on the same model, in your browser.
Watch the SysML v2 tour, which builds a model from an empty project, or the SysML v2 highlights, one feature each.
One model
Text, views and engineering pages share one model
A SysMLSystems Modeling Language A graphical modeling language for systems engineering, based on UML, with block, activity, state machine and parametric diagrams. v2 project holds one model of packages, definitions, usages and relationships. The Editor shows it as text, the views draw it, and Holarch's lifecycle pages read and write it. A change in any of them shows in all the others.
Requirement status, verification results, risks, tasks and view layouts are kept next to the model and linked to its elements by id, so the links survive renames and moves.
Write the model as text
- Applied as you pause. Text that parses is applied to the model as one undo step. Text with an error stays a draft, and the model keeps its last good state.
- Problems as you type. Errors and warnings are marked in the gutter and underlined, with the message on the line.
- Completion, go to definition and rename. Names and keywords complete at the cursor, ⌘ / Ctrl-click jumps to a declaration, and renaming a declaration updates every reference.
- Insert ▾. Lists the constructs that fit at the cursor, such as parts, ports, connections, actions and requirements, with fields to fill in.
- Standard library. Units and quantities such as
MassValueand[kg]come from the standard library, browsable in the project.
package Drone {
private import ISQ::*;
private import SI::*;
part def Battery {
attribute mass : MassValue = 0.4 [kg];
}
part def Quadcopter {
part battery : Battery;
}
}A first model from the getting started guide. Typing it creates the package, both part definitions, the attribute and the part.
Edit the model in views
Each view is a view usage in the model, so it is part of the text too. Drawing in a view writes the text at once, as one undo step. Views have the same tabs, toolbar, Add panel, inspector and exports as every Holarch diagram.
General View
Definitions and usages as boxes, with specialization, typing, composition and requirements.
Interconnection View
Nested parts with ports on their border, connections, interfaces and item flows.
Action Flow View
Actions, successions, decisions, forks and the item flows between parameters.
State Transition View
States, nested and parallel regions, and transitions.
Sequence View
Lifelines and the messages between them, in order.
Grid and Geometry Views
Element tables and relationship matrices; parts drawn in 2D at the place and size their attributes give.
Requirement, Use Case, Parametric and Package Views are presets of the General View. The Spider, Hierarchy, Tree, IDEF0Integration Definition for Function Modeling A function-modeling method: each box is a function, with inputs, controls, outputs and mechanisms on fixed sides. and FFBDFunctional Flow Block Diagram A diagram of functions in the order they run, with branches, loops and parallel paths. diagrams and the Functional Analysis page work on the model too.
Systems engineering on the model
Holarch's engineering pages, on SysML v2
SysMLSystems Modeling Language A graphical modeling language for systems engineering, based on UML, with block, activity, state machine and parametric diagrams. v2 projects keep Holarch's lifecycle rail: the same pages, layout and controls as LMLLifecycle Modeling Language An open modeling language with a small set of classes and relationships that covers a system's whole lifecycle. Holarch models are LML models. projects, working on the SysML v2 model.
Requirements in documents
A requirements document holds the requirement usages of a package, with outline numbers from their short names. Check quality, approve, mark values TBDTo Be Determined A requirement value or detail that is not known yet. Holarch tracks TBDs with an owner and a due date. or TBRTo Be Reviewed A requirement value that is filled in but still needs to be confirmed., and review suspect links.
Verification and the RVTM
The RVTMRequirements Verification Traceability Matrix A table of each requirement with how it is verified, the tests that verify it and their latest result., verification cases, the traceability matrix and Model Checks read the model's satisfy and verify relationships.
Behavior analysis
Edit an action's flow in FFBDFunctional Flow Block Diagram A diagram of functions in the order they run, with branches, loops and parallel paths. terms, with functions, AND, OR and loop constructs. Simulate action flows, including Monte Carlo runs, and check the results against a requirement.
Values, budgets and trades
Values carry units and are evaluated in the model. Parametric Views show Pass or Fail per constraint and solve values. Budgets & TPMsTechnical Performance Measure A key technical parameter, such as mass or power, tracked over time against its target and threshold. and trade studies use the same values.
Interfaces
The Interface Register, ICDsInterface Control Document The agreed definition of an interface between two systems: what crosses it, how, and who owns it. Holarch also has an Interface Control Diagram., N²N-squared A square chart with elements on the diagonal and what passes between them in the off-diagonal cells. Used to find and check interfaces. diagrams and the Physical I/O Diagram work on the model's connections, interfaces and item flows.
Risks, changes and baselines
Link risks, decisions and tasks to model elements. Change requests show the text difference. A baseline holds the model, and Compare lists what was added, changed, moved and renamed.
DoDAF and UAF
Framework products are views of the model. Capabilities, systems and other framework concepts are SysML v2 metadata, which other tools read as plain metadata.
Documents and reports
Live values, live tables, RVTM and matrix blocks and pictures of views fill specifications and review packages, exported to Word, Excel and PDF.
Collaboration
Edit the model together: changes arrive live in the text, views and pages. Roles, comments with @mentions, assignees and element history work as in every project.
Exchange and automate
- Files. Import and export SysMLSystems Modeling Language A graphical modeling language for systems engineering, based on UML, with block, activity, state machine and parametric diagrams. v2 text (
.sysml, also as a.zip) and SysML v2 JSON. Import shows what changes before it applies, as one undo step. - Model repositories. Pull from and push to a branch of a repository that offers the Systems Modeling API. Pull lists each difference, and you choose what to apply.
- Other tools read Holarch. A read-only Systems Modeling API serves the project's current model to other SysML v2 tools.
- REST API and MCP, on every plan. Scripts and AI tools such as Claude read, search and check the model and propose changes. Nothing changes until a person reviews the proposal in Holarch and applies it.
AI on the model
- Individual and Team plans: Ask AI answers questions about the open model and proposes changes to it. It reads only the elements a question needs, never the whole model.
- A change that would add errors to the model is not offered. You review each proposal, with the text difference, and apply it as one undo step.
- Free plan: Ask AI answers questions about SysMLSystems Modeling Language A graphical modeling language for systems engineering, based on UML, with block, activity, state machine and parametric diagrams. v2 and Holarch from Help and the Docs.
- With MCP, the AI tool you already use can work on the model on any plan. See Pricing.
Who it is for
- Teams that already model in SysMLSystems Modeling Language A graphical modeling language for systems engineering, based on UML, with block, activity, state machine and parametric diagrams. v2, or that exchange models with SysML v2 tools and repositories.
- Engineers who want requirements, verification, interfaces, risks and plans on the same model as the SysML v2 text.
- Students and instructors learning the SysML v2 textual notation, free on the Free / Academic plan.
- New to MBSEModel-Based Systems Engineering Systems engineering that keeps requirements, behavior, structure and tests in one connected model instead of separate documents.? Start with an LMLLifecycle Modeling Language An open modeling language with a small set of classes and relationships that covers a system's whole lifecycle. Holarch models are LML models. project: it has every Holarch page and guided checks at each step. See LML.
How to start
- Open the demo. On Manage Projects, choose Project Files ▾ → New Demo Project → Hybrid Car (SysMLSystems Modeling Language A graphical modeling language for systems engineering, based on UML, with block, activity, state machine and parametric diagrams. v2): a finished model with views, requirements, verification, risks and DoDAFDepartment of Defense Architecture Framework The US DoD framework for describing architectures as a set of viewpoints and products, such as OV-1 and SV-1. products.
- Create a project. Click + New Project and choose SysML v2 under How will you model this system?
- Convert an LMLLifecycle Modeling Language An open modeling language with a small set of classes and relationships that covers a system's whole lifecycle. Holarch models are LML models. project. Make a SysML v2 Copy… in the project's ⋯ menu creates a new SysML v2 project. The original stays as it is, and a report lists what converts and what does not.
- Import files. Choose Project Files ▾ → Import SysML v2 Files… to start from
.sysmlor SysML v2 JSON files.
What Holarch supports
Holarch's SysMLSystems Modeling Language A graphical modeling language for systems engineering, based on UML, with block, activity, state machine and parametric diagrams. v2 projects are based on the OMGObject Management Group The standards body that maintains UML, SysML, UAF and XMI. SysML v2 specification and support a subset of the language: packages, definitions and usages, ports, connections, interfaces and flows, actions and states, requirements, constraints and verification, use cases, views, values with units and metadata. The Docs list what is supported and what is not yet, such as KerML files and simulating state machines. See What Holarch supports.
Building your own SysML v2 tool?
The language engine behind these projects is available for licensing: it parses, resolves, checks and evaluates SysMLSystems Modeling Language A graphical modeling language for systems engineering, based on UML, with block, activity, state machine and parametric diagrams. v2 and KerML text in the browser or on your server. See Holarch Language Engine.