To generate models of branched and reticular urban layouts, under three different forms of growth (linear, radial, strips), a program designed on AutoLISP “† for the AutoCAD “† V-2000 has been proposed. The generated models are both graphical as well as mathematical, and for each case are produced, considering the two variables assumed as inputs: the number of houses and the number of grouping units. The mathematical data is automatically saved in a MSExcel Æ spreadsheet created through a direct connection established from the AutoCAD Æ V-2000.