Abstract
Although functional design is crucial within a design process, difficulties in dealing with functions prevented traditional CAD technology based on geometric modeling from supporting functional design. This paper proposes a new methodology for modeling functions, called FBS (Function-Behavior-State) modeling. The FBS modeling represents a function as an association of the designer's intention and a behavior needed for realizing the function. This paper also describes a computer tool to support functional design based on the FBS modeling. This tool, called the FBS Modeler, supports a designer not only to verify design solutions with qualitative simulation but also to generate design solutions through decomposition of specified functions and embodiment of decomposed functions. Experimental design case studies demonstrate the importance and advantages of the FBS modeling.
