Drawing communication diagrams

Communication diagram is designed for illustrating the dynamic view of the system. It emphasizes the structural organization of the objects' send and receive messages.

Creating communication diagram

Click on UML on toolbar and select Communication Diagram from the drop down menu.
Right click on Communication Diagram in Diagram Navigator and select New Communication Diagram from the popup menu.
Select File > New Diagram > UML Diagrams > Communication Diagram from the main menu.

Create communication diagram

Creating actor

To create actor, click Actor on the diagram toolbar and then click on the diagram.

Create actor

Creating lifeline

To create lifeline, you can click LifeLine on the diagram toolbar and then click on the diagram.

Alternatively, a much quicker and more efficient way is to use the resource-centric interface. Click on the Message -> LifeLine resource beside an actor/lifeline and drag.

Create lifeline

Move the mouse to empty space of the diagram and then release the mouse button. A new lifeline will be created and connected to the actor/lifeline with a link (the line) and a message (the arrow).

Lifeline, link and message created

Creating message on link

To create message on link, click its Create Message resource.

Create message on link

A message will be created on the link.

Message created on link

Editing sequence number of messages

To edit sequence number of messages, for example, to show certain messages are in nested level of interaction, right-click the diagram and select Reorder Messages... from the pop-up menu.

Reorder messages

When the Communication Diagram Specification dialog box appears, the Message tab is opened by default. Double click on the Sequence # cell of a message to edit it. Click OK button to apply the changes.