Why Model? Modeling achieves four aims: Helps you to visualize a system as you want it to be. Permits you to specify the structure or behavior of a system. Gives you a template that guides you in constructing a system. Documents the decisions you have made. You build models of complex systems because you cannot comprehend such a system in its entirety. You build models to better understand the system you are developing. Object Oriented Analysis and Design 4Object Oriented Analysis and Design 4 Why Model?  Modeling achieves four aims: ▪ Helps you to visualize a system as you want it to be. ▪ Permits you to specify the structure or behavior of a system. ▪ Gives you a template that guides you in constructing a system. ▪ Documents the decisions you have made.  You build models of complex systems because you cannot comprehend such a system in its entirety.  You build models to better understand the system you are developing