Abstract: A modeling system that arranges the model in a hierarchical structure of communicating and independently executing object modules controlled by an overall supervisor. Each object represents a component or a system and includes an object controller which communicates with other object modules, an object error checker and an object model. The objects communicate through a database accessible by all objects. The structure of the object module and the hierarchical structure itself are standardized allowing new components or systems to be added by adding a standard object module which includes an object model that is unique to the object being modeled. The controller for an object causes subobjects upon which the object model depends for data to be executed prior to execution of the object model. Such bottom up model traversal insures that models do not execute until all needed data is available. The error check module checks the controller and model modules to make sure they are executing properly.