Capella — The Complete Guide: Free Model-Based Systems Engineering with Arcadia

Capella is a model-based systems engineering (MBSE) tool that started at Thales and was handed to the Eclipse Foundation as open source. Instead of a long requirements document and scattered diagrams, the whole system lives in one model, and every diagram is a view of that same model. It is built on Eclipse and runs on Windows, macOS and Linux.

Capella

Eclipse Foundation (originated at Thales)

Model-based systems engineering with the Arcadia method: from operational analysis to physical architecture. Used in aerospace, rail and automotive.

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What you get

Built-in Arcadia method — defined working levels: operational, system, logical and physical.
Traceability between levels — linking every function to the component that implements it and the need behind it.
Ready-made diagrams — functional dataflows, architecture, scenarios and modes and states.
Validation checks — finding unallocated functions and missing interfaces.
Add-ons — extensions for requirements, extra analyses and Python scripting.

How it differs from SysML

Capella does not implement SysML to the letter. Its language draws on it but is simpler and tied closely to the method. The upside: a new engineer always knows what to do next. The downside: if a client requires a SysML model, you need another tool. The tool itself is free; advanced team-collaboration services are sold commercially by third parties.