Creating gates in sequence diagrams

You can add formal and actual gates to sequence diagrams. Gates are messages that have parameters that pass information. Formal gates can end or start from the diagram edge and extend to a lifeline. An actual gate can start or end from an interaction use.

Before you begin

You must have a lifeline or an interaction use in a sequence diagram.


  1. In the Palette, click a message type.
  2. In the interaction frame, click the edge of the frame and drag the cursor to a lifeline or select the lifeline as the source and drag the cursor to the interaction frame. An actual gate is created if the source or target is an interaction use.
  3. Type a name for the message. A message is created with one end that contains an arrow in a square around it, which represents a gate.