This paper describes an attempt to produce an accurate computer model of a particular type of membrane, the Anotec cellular ceramic membrane, with the aim of using this model as a tool to predict the performance of the membrane, It is explained how models have been developed for both the symmetric and the asymmetric Anotec membranes based on a mathematical construction known as a Voronoi tessellation. For both cases good qualitative agreement is seen between graphical output of the models and SEMs. For the case of the symmetric membrane there is also good quantitative agreement between statistics from the model and data from image analysis of a membrane of this type. The structural model has been used in calculations to predict the how of clean solvent through the membrane over a range of transmembrane pressure differentials. Good agreement was obtained between the calculated and measured data.