Actions
SysML 2 Actions are used to model processes that describe the functional behavior of a system. They capture a set of steps that are executed in a predetermined sequence. These steps may comprise conditions and repetitions of steps based on certain conditions. The use of Actions in a model enables system engineers to specify and analyze the behavior of a system by defining the processes used by critical system functions. The following are some Actions with reference to modeling:
• Starting the engine of a car
• Taking a photograph
In Modeler, Actions are defined by Action definitions. These definitions may have features with directions such as in, out or inout. Features that have in or inout directions are the input parameters of the action and features that have out and inout are the output parameters of the action.
An Action usage inherits all of the features of its definition and it also can define and redefine its own parameters. Actions can be decomposed or broken down in to several lower level action usages creating an action tree. An Action definition can be subclassified while an Action usage can be subsetted or redefined.
Creating an Action Definition
To create an Action Definition from the ribbon
1. On the System Structure Diagram, on the System Structure Diagram ribbon, click the 
Action Definition button.
Action Definition button.2. Click on the empty space on the diagram to create the Action Definition.
To create an Action Definition from the context menu
1. Right-click on the Package or Package library in which you want to create the Action Definition.
2. Select > > > . This creates an Action Definition within the Package or Package Library. To add it to the diagram, drag the Action Definition and drop it on the diagram.
Creating an Action Usage
To create an Action Usage
1. On the System Structure Diagram, on the System Structure Diagram ribbon, click the 
Action button.
Action button.2. Click on the empty space on the diagram to create the Action Usage.
To create an Action Usage from the context menu
1. Right-click on the Package or Package library in which you want to create the Action Usage.
2. Select > > > . This creates an Action Usage within the Package or Package Library. To add it to the diagram, drag the Action Usage and drop it on the diagram.