A simple, low cost, and universal automatic 3-D acquisition system was developped using active triangulation. Its main characteristics are: - its speed of acquisition (about 1 minute per object), - the density of its sampling (from 30,000 to 250,000 measures per object), - the structured lattice of the resulting data (distributed on parallel and meridian equidistant lines). From these data, it is possible to use several techniques of surface approximation to compress the information: some of them are presented here, with their respective performances (quality, compression rate, complexity of programming). They are divided into two main classes: - planar approximations, - spline function approximations. We also present several advantages of the resulting data base which is structured like a picture data base. We can take advantage of this structure to develop very fast processing techniques.