Recently there has been much attention to MDL and its effectiveness in automatic shape modelling. One problem of this technique has been the slow convergence of the optimization step. In this paper the Jacobian of the objective function is derived. Being able to calculate the Jacobian, a variety of optimisation techniques can be considered. In this paper we apply steepest descent and show that it is more efficient than the previously proposed Nelder-Mead Simplex optimisation.