We previously [Jacquier 5, Gruy F Approximation of the light scattering cross-section for aggregated spherical non-absorbent particles. JQSRT 2008;109:789-810] reformulated the anomalous diffraction (AD) approximation to calculate the light scattering cross section of aggregates by introducing their chord length distribution (CLD). It was applied to several ordered aggregates. This new method is entitled ADr, with. the r for rapid because this one is at least 100 times faster than the standard AD method. In this article, we are searching for an approximated expression for CLD suitable all at once for ordered and disordered aggregates. The corresponding scattering cross-section values are compared to the ones coming from the standard AD approximation.