The SysML callout notation
I’ve just found this question in a sysml discussion forum:
Is it really not possible to place requirements objects on an Activity, State Machine, or several other similar behavioral diagrams?
Yes, it is not allowed to put requirement elements on a state machine or activity diagram. Since it is essential to show such cross cutting relationships SysML provides the callout notation. A comment symbol is attached to the state or action or to any other element in the state machine/activity diagram. The text inside the comment describes the relationships to the requirements. Although it looks like a simple comment it is a formal representation of the model. A good SysML tool could display the callout notation automatically.
SysML Callout notation
The callout notation works for the allocate and the requirements relationships.
7 Responses
Question: Is it legal to have a callout notation attached to the frame of the diagram?
Yes, it is allowed. You find an example in Appendix A of the SysML 1.7 specification (http://www.omg.org/spec/SysML/1.7/Beta1). The specification states: “The diagram description can be defined by a comment attached to a diagram frame as indicated in Fig. A.2”
Thank you so much for the quick reply! And thanks for the reference to that wonderful document!