Object technologies lend themselves nicely to modeling the real world. An Example Armed with a fresh object perspective, you can more intuitively model the world around you. To illustrate, I'll continue with the automobile theme and build an automobile simulator. Start by Drawing a Class Diagram Objects are derived from classes of objects. For example, you don't drive an automobile per se, but a particular instance of an automobile, like a Ford F150 truck or a Chevy Blazer.
Class diagrams offer a static view of classes and their relationships to each other.
Figure 1 is a Booch notation representation of an Automobile class and an Engine class. In Booch, notation classes are drawn as a dashed-line cloud. You can draw classes as circles, ovals or blobs. What really matters is that you establish an understanding of the object classes and their relationships. However, taking the time to learn an established diagraming technique gives you the power to draw expressive diagrams.