Nature has served as inspiration for product design throughout history. Applications range from poetic translations of form to utilization of primary functional principles. This paper describes a generally applicable design methodology for transforming natural functional principles to feasible product design. From a formulation of design demands, which need not necessarily be very precise, the approach continues with a study of natural objects (anaimals, plants) which are subject to the same demands. From this study, the working principle(s) are derived. This (these) are then clarified through illustrative models, which should be simplified as much as possible. The simplified principle may now be evaluated and transformed into practical design. The methodology is clarified through examples, taken from a series of extended workshops held atAalborg University .