MEPLAN and DORTMUND, two urban/regional models which originated in two countries with significantly different planning cultures - the United Kingdom and Germany - are compared. In the first part of the paper it is demonstrated that the political and intellectual contexts in which the two models were developed had a significant influence on the selection of processes to be modelled, the theories applied, the definition of submodels, the solution algorithms, and the kinds of results the models were designed to produce - as well as their application histories. In the second part, a unique exercise is reported in which three urban/regional models, MEPLAN, DORTMUND, and LILT (Leeds Integrated Land-use Transport model) were applied to the same city, Dortmund. In the final section, a more recent experience is reported in which MEPLAN was applied in a wider international context involving research groups from five countries. It is shown how the model stimulated the discussion between the representatives of different national research traditions and helped to arrive at a synthesis between the pieces of information flowing from tangible and intangible sources. (A)