Inherited Characteristics 
When we say that characteristics are inherited, we mean that a class passes down its characteristics and their values to all its subordinate classes in a class hierarchy. The subordinate classes do not contain the characteristic.
The advantage of characteristic inheritance is that you only need to enter a characteristic once, in a class at the top of a hierarchy, and it is used in all classes in the hierarchy. This saves your having to enter the characteristic separately for each class.
When you set up a class hierarchy, the subordinate classes in the hierarchy inherit the characteristics of the superior classes. On the characteristic value assignment screen, you see characteristics that are inherited from superior classes, as well as the characteristics that are assigned directly to the class.
Choose 
Extras 
User Settings, 
on the Value Assignment tab page to hide inherited characteristics on the screens for assigning characteristic values and finding objects.
The following example shows three classes in a hierarchy. The top class for fasteners contains the characteristic Thread Type.
The Bolts class doesn't contain the characteristic. However, as a result of the assignment to the Fasteners class, the Bolts class inherits the Thread Type characteristic.
The subordinate class inherits the Thread Type characteristic from the Fasteners class and the Head Shape characteristic from the Bolts class.
