The model is a grouping mechanism for OV-5 diagrams. You specify properties such as model viewpoint, purpose, and description for the model. In the model you build an OV-5 context diagram, and decompose that diagram with multiple child OV-5 constraint diagrams.
In System Architect the name of the model that you associate OV-5 diagrams with is actually called an IDEF0 model.
Context diagrams
Every OV-5 Context (or A-0) Diagram must be associated with a model. System Architect forces you to define a Model Name for the diagram when you create it. This is in keeping with the IDEF0 specification.
Constraint diagrams
To provide flexibility in modeling, you are not forced to define a model for non-Context OV-5 diagrams. You can add one later. When you add a model name later, you can choose either of the following options.