Conceptual design of modern products has become complex due to an increasing number of subsystems and components comprising the system and the multi-disciplinarity of the employed design knowledge. The paper proposes a product modeling framework and a CAD system for conceptual design of complex products focusing on hierarchical system decomposition and consistency management of design information across different engineering disciplines. The framework and CAD system support these tasks with concurrent development of functional and parameter-level product descriptions and comprehensive evaluation of these descriptions from functional, parameter-level, structural, and behavioral aspects. A conceptual design case at a printer manufacturer is demonstrated.