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Create a Timing Message

To create a Message in a Timing diagram, at least two Lifeline objects (State or Value) must be created first, each with existing transition points.

How to:

To create a Message between Lifelines, follow the steps below:




Click on one of the Lifelines in the Timing diagram


Select the Message icon from the Timing Relationships page of the Toolbox (More tools | Timing)


Drag the cursor onto the Lifeline at the point at which the Message originates

The Timing Message dialog displays (if not, double-click on the Message)


The dialog consists of a set of transition points

Each transition point can be defined with the properties listed in the following table




Defines the lifeline where the message originates


Defines the lifeline where the message terminates

The following properties are set by default when a Message is created by dragging the cursor between two Lifelines.



Start Time

Specifies the start time for a message

End Time

Specifies the end time for a message


The name of the message

Time Observation

Provides information on the time of a sent message

Duration Observation

Indicates the interval of a Lifeline at a particular state, begun from a message receipt

Transition To

The state in the target Lifeline that the Message points to


The occurring event

Time Constraint

The time taken to transmit a message

Duration Constraint

Pertains to a lifeline's period at a particular state

The constraint could be instigated by that Lifeline's receipt of a message

The following diagram shows an example of a configured Message:


See UML Superstructure Specification, v2.1.1, figures 14.30 and 14.31, p. 520.


  • You can move the source end of the Message freely along the source timeline; however, the target end (arrow head) must attach to a transition
  • If you create a new Message and do not give it a target transition, it automatically finds and attaches to the nearest transition; if you move the target end, it drags the transition with it

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