After you have created the top-level Context, or A-0, diagram, you can decompose its Operational Activity by creating a child Constraint, or decomposition, diagram.
The modeling software does not impose a set limit of diagram levels that you can create to reveal the complexity of parent symbols. The Constraint diagram is a child IDEF0 diagram that can either be created or attached.
1 In the diagram containing the operational activity to decompose, right-click the operational activity symbol; then click Child Create.
The Child Create dialog box opens showing the name of the symbol on the parent diagram in the Name field and the diagram type of the parent diagram highlighted in the list box.
2 If you do not want to use the name of the object symbol on the parent diagram as a name for the child diagram, type a new name in the Name field.
You can change these values; however, to conform with the IDEF0 specification, it is a best practice to accept the default values.
3 Click OK; when prompted to save the parent diagram, click Yes.
The child diagram is created.
4 In the Child Diagram/OV-5 Activity Model dialog box, accept the default value of 4 activities or enter the number of activities for the child diagram.
5 Click OK.
Once you create a child diagram for an operational activity, the System Architect modeling software draws a shadow underneath the parent operational activity.
By default, swimlanes appear on the child diagram. You can remove the swimlanes by opening the diagram properties and selecting None on the Swimlanes tab.
After you have created the child diagrams, you need to populate the diagram and move the ICOM arrows to their correct positions.