The first step in drawing an NOV-5 Activity Model is creating the Context or A-0 diagram.
Prerequisite
First, consider the model that this IDEF0 Context diagram will represent. You can create a model before hand, or create one as you start the IDEF0 diagram.
Procedure
1 Click Tools > File > New Diagram > NOV-5 Activity Model, and type the name of the diagram.
2 Click OK.
3 In the NOV-5 Activity Model window, select the Context Diagram checkbox.
4 In the Model Name field, type in the name of a new model or click the Choices button; then drag an existing model name to the box.
Note If you type in the name of a new model, you can optionally click Define to define the model. You can also do this later. The model should contain information regarding its purpose, scope and viewpoint.
5 Click OK.
A new diagram is created containing a symbol representing the model in its lower-left-hand corner. The diagram displays one unnamed activity and the IDEF0 Model Name.
From this diagram you can create child, or decomposition, diagrams to develop more detailed views of the function. IDEF0 child diagrams depict several sub-functions to describe the parent function.