OpenROAD system classes are organized in a hierarchy. In this hierarchy, as depicted on the OpenROAD Workbench Class Browser, a system class that is below another class is considered its subclass and a system class that is above another class is considered its superclass.

Each subclass inherits the attributes and methods defined for all its superclasses. For example, ButtonField is a subclass of ScalarField. Thus, the complete list of attributes and methods available for ButtonField includes the attributes defined for ScalarField and its superclasses (ActiveField, FormField, FieldObject, and Object) and those defined specifically for ButtonField.

For more information, see Class Browser in the Workbench User Guide.