Glossary · Systems engineering and MBSE
Requirement diagram
German: Anforderungsdiagramm
In SysML, a requirement diagram shows requirements as model elements and their relationships to each other and to other model elements, such as containment, derive, refine, satisfy, verify and trace.
- Systems engineering
- Verification
In one sentence
A SysML requirement diagram shows requirements and their derive, satisfy, verify and trace relationships to other model elements.
Example
A requirement diagram shows the safety requirement 'stop robot on door opening' derived from a hazard, satisfied by the 'Door interlock' block and verified by a test case.
How it applies
- Engineering: Requirement diagrams bring requirements into the model, so traceability to structure and behavior is kept in one place.
- Verification: The «verify» relationship links requirements to test cases; missing links show unverified requirements.
- Documentation: The documentation team can use satisfy and trace relationships to find which requirements a documented function fulfills, which helps keep manuals consistent after changes.
- Review: Requirement diagrams are best used for focused views, for example one safety function and its derivation, rather than for showing hundreds of requirements at once.
Requirement diagram vs. requirements tool
Large requirement sets are often managed in a dedicated tool and synchronized with the model. The requirement diagram then shows selected requirements and their links, not the complete specification.