The first step in drawing an OV-5 Activity Model is creating the Context or A-0 diagram. To create a Context diagram:
1 First you should have an idea of the model that this IDEF0 Context diagram will represent. You may create a model before hand, or create one as you start the IDEF0 diagram.
2 To create a new OV-5 Activity Model diagram, select File, New Diagram, OV-5 Activity Model, and type in the name of the diagram. Click OK. The OV-5 Activity Model Diagram dialog appears.
3 Toggle on the Context Diagram checkbox.
4 In the Model Name field, type in the name of a new model or click the Choices button and drag-and-drop in an existing model name. 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 to close the dialog and create the OV-5 diagram.
The diagram will display one unnamed activity and the IDEF0 Model Name.
What to do next
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.