Functional models are representations of the energy, material and signal transformations that occur through the expected or normal operating condition of a product. As the complexity of products increases, there are often multiple dimensions to their operation in addition to their nominal operating state, e.g., crash protection systems in a car or laser leveling and stud finding combined in a single tool. Here system state is used to represent the different operational dimensions of a product, and a representation scheme that allows designers to fully explore system functionality of products with multiple system states is explored. Previous work in process and functional analysis is integrated to better represent complex systems with multi-dimensional system functionality. Process and functional modeling are integrated to produce a new function design framework supporting user-defined fidelity of hierarchical models for functional representation. An example modeling a complete automobile life cycle illustrates the development of integrated process and functional models within a complex system analysis.