Abstract: A system is disclosed for materializing in space a point whose coordinates in a system of reference axes are known, comprising:an optical aiming apparatus, occupying a pre-determined position with respect to said system of axes and making it possible to determine, in said system of axes, the coordinates of any point aimed at, anda tooling assembly comprising a stand, one part at least of which is movable with respect to said system of axes and a hemispherical ball joint mounted in a spherical concave seat fixed to said movable part of the stand, the center of said ball joint being marked so as to be visible by said aiming apparatus.