Some problems relating to the numerical simulation of urban ambient environments

The author draws attention to certain problems encountered in the business of simulation of urban ambient environments. He aims, in the first place, to situate the whole problematic of the urban environment in relation to recent thinking on the subject of the design and administration of cities and urban projects. He then approaches the theoretical and methodological problems posed by a double characterisation of environment in terms of objective and subjective elements. Finally, drawing from CERMAs own experience, he lists a series of practical obstacles whose solution can surely provide a focus for the international cooperation in research which is strongly urged in this paper.