After you have created the top-level Context (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.
To create an OV-5 child diagram
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. You can change these values, but it is a best practice to accept the default options.
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.
3 Click OK; then click Yes to save the parent diagram.
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. If you are unsure, leave the default.
5 Click OK.
When you create a child diagram for an operational activity, the modeling software draws a shadow underneath the parent operational activity.
Note 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.
Next
After you have created the child diagrams, you need to populate the diagram and move the ICOM arrows to their correct positions.