Published online by Cambridge University Press: 24 July 2013
Function-based design and modeling have been taught, studied, and practiced in various forms for several years with efforts centered on using function modeling to help designers understand problems or to facilitate idea generation. Only limited focus has been placed on potential use for qualitative and quantitative reasoning and analysis of the design concept. This potential for early stage analysis has not been fully explored partly because computational reasoning tools have not been developed for this express purpose. This paper presents a set of requirements and their justification to realize this design enabling tool. The requirements include coverage, consistency, validity against physics laws, domain neutrality, physics-based definitions, normative and descriptive modeling, and qualitative and quantitative modeling and reasoning. Each requirement is defined in concrete terms and illustrated with examples and logic. With the requirements for function-based reasoning and representation clearly identified, future research toward formalizing of function-based design will be more focused and objective validation of proposed representations against these requirements would be possible.