VOPC Class Diagrams A VOPC class diagram shows a use-case realization's participating classes and the relationships among those classes. ◆ It shows all classes whose instances collaborate to perform the use case and their relationships. It ensures consistency in use-case implementation across subsystem boundaries. Object Oriented Analysis and Design 8Object Oriented Analysis and Design 8 VOPC Class Diagrams  A VOPC class diagram shows a use-case realization’s participating classes and the relationships among those classes.  It shows all classes whose instances collaborate to perform the use case and their relationships.  It ensures consistency in use-case implementation across subsystem boundaries