SysML Diagram Interchange Architecture

The Diagram Definition (DD – previously known as Diagram Interchange (DI)) is a format to exchange diagram data between tools. The data about diagrams is separated from the data about the model information. The interchange format for the model data is XMI (XML Metamodel Interchange; see XMI specification page).

The following figure depicts the whole picture of the SysML Diagram Interchange architecture. As well as SysML is an extension of UML, the SysML Diagram Interchange is an extension of the UML Diagram Interchange. And the UML DI is a specialization of the generic DD.

SysML Diagram Interchange Architecture

SysML Diagram Interchange Architecture

Let us have a look on a simple example of a single use case. The next figure shows a SysML use case diagram with useless use case:

A useless use case

A useless use case

The model data of the use case is an instance of the metaclass UseCase with the appropriate properties. The next figure depicts an extract of the model data by a instance specification:

Instance of metaclass UseCase

Instance of metaclass UseCase

Using XMI exchanges the data of the use case in a XML-based format.

The diagram information of the use case covers data like position and size of the shape on the diagram. The information is an instance of the shape metamodel element of the DD:

Diagram definition data of a use case

Diagram definition data of a use case

The SysML Diagram Interchange is an extension of the Diagram Definition. It covers special notation aspects of SysML. For instance the dashed control flow arrows in an activity diagram. The following figure depicts how this notation is implemented in SysML:

Diagram definition of a SysML Activity Diagram

Diagram definition of a SysML Activity Diagram

The SysML Diagram Interchange is part of the non-normative appendix of the SysML 1.4 specification. That means a tool vendor is not required to provide the format to be 100% SysML compliant. However it is strongly recommended that it is provided by SysML modeling tools. Unfortunately I do not know a modeling tool that has implemented the diagram interchange format. If you know one, please drop a note as comment to this blogpost.

This was the last post of my blogpost series about the changes of SysML 1.4.

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