John Gero’s Function-Behaviour-Structure model of designing: a critical analysis

Over the last 12 years, the design research group at the Key Centre for Computing at the University of Sydney has been developing an extensive model of designing, looking at designing as a process in which the concepts of function, behaviour and structure of artefacts play a central role. In this paper, we critically analyse this model of designing, focussing on its internal clarity and external empirical validation. We review the model and present the definitions of the key concepts function, behaviour and structure. In doing so we show that one can distinguish at least two different versions of the model. Finally, we raise fundamental questions about the precise location of the transition between structural and intentional descriptions of artefacts in these versions, and about the empirical status of the model as a whole.