Messages in Communication diagrams can only be depicted on connectors; thus, you should draw a connector before assigning a Message to it.


The following steps show you how to work with messages:

Assigning a message to a connector

To assign a message to a connector


  1. On the diagram palette, click the button corresponding to the desired Message type.
  2.  Click a desired connector on the diagram pane. A Message arrow will be placed on the selected connector.

    A Message flow has two directions: right and left. Choose one of them by clicking the associated button on the diagram palette.

Setting/removing the advanced numbering of messages

To set/remove the advanced numbering of messages


  1. From the diagram shortcut menu, select Numbering.
  2. Select to set, or clear to remove the Use Advanced Numbering.

Changing current message numbering

To change current message numbering


  1. From the diagram shortcut menu, select Numbering > Change Numbering.
  2. Increase, decrease, and / or change the level of numbering in the Change Communication Numbering dialog.
    Change Communication Numbering dialog


If the Edit button is inactive, remove the automatic advanced numbering of Messages.


Displaying messages

If you want to display messages on connectors in the Communication diagram you must first implement the following conditions (see the figure below):

The Loan Library Item Communication diagram which contains two lifelines and the connector between them.


To display messages


  1. Select the connector between lifelines.
  2. Perform one of the following actions:
    • Right-click the connector to open the shortcut menu, and select Display > Display Messages.
    • On the diagram toolbar, click Display,and select Display Messages.
    The Display Message command.
  3. In the opened Select Messages dialog, select the messages you want to display, and click OK.
    The Select Messages dialog.
    Messages of the selected connector are displayed on the diagram pane.
    Messages of the selected connector are displayed on the diagram pane.


Sample model

The model used in the figures of this page is the Communication diagram sample model. To open this sample do one of the following:

  • Download communication diagram.mdzip.
  • Find in modeling tool <modeling tool installation directory>\samples\diagrams\communication diagram.mdzip.