Two elements are used to model Events; the:
- Send Event which models the generation of a stimulus in the system and the passing of that stimulus to other elements, either within the system or external to the system
- Receive Event, depicted as a rectangle with a recessed 'V' on the left side, which indicates that an event occurs in the system due to some external or internal stimulus; typically this invokes further activities and processing
Send and Receive Events can be added from the Analysis, State and Activity Element pages of the Toolbox.
If you should select the wrong type of event, or otherwise want to change the type, right-click on the Event and select the 'Advanced | Make Sender' or 'Advanced | Make Receiver' option, as appropriate.