Résumé : We present an algorithm to determine all the possible geometries of Gough-type 6 D.O.F. parallel manipulators whose workspace has to include a desired workspace. This desired workspace is described by a set of geometric objects, limited here to points, segments and spheres, describing the location of the center of the moving platform, the orientation of the platform being kept constant for each given object. This algorithm takes into account the leg length limits, the mechanical limits on the passive joints and interference between links.