Science museums define the objectives of their exhibitions in terms of visitor learning outcomes, yet exhibition engineering staff lack theoretical and empirical research findings on which to base the creation of these educational environments. Here, a first step towards providing such research is reported. Museographic transposition was used as an analytical framework to investigate the development of an existing museum exhibit on animal adaptations to darkness. The analysis yielded a descriptive model of exhibition engineering as a three-stage process in which simultaneous processes of epistemological development and museum-pedagogical development result in the curatorial brief which forms the basis of the subsequent museographic development of the physical exhibit. Examples are discussed which illustrate the use of the model in identifying exhibition inconsistencies, but also in generating new ideas for exhibition engineering. The potential for further developing the model is discussed.