The invention relates to the design of layouts for a room in which a user wishes to position elements figuring in a collection of catalogs. Prior art systems only allow incremental construction by making direct selections from one or more catalogs. The inventive system and procedure allow rapid, overall construction of several solutions satisfying a certain number of constraints determined by the room, the user or the distributor of the equipment to be positioned, as well as rules derived from experience in the field of the equipment concerned. The method is subdivided into the steps of spatial analysis, definition of layout templates, selection of candidates from the collection of catalogs and optimization of the positioning. The system permits simultaneous visualization in three dimensions of optimum solutions and the printing of two-dimensional assembly drawings. The procedure and the system are preferably applicable to kitchen layouts.