In the DOM, the calculation of a radiative source term at a given point is based on the discretization of the Radiative Transfer Equation (Eq.) according to a chosen number of discrete directions , associated to the corresponding weights , contained in the solid angle , and where ( ) are directional cosines. Different angular discretizations may be used. In a recent study, Koch and Becker [#!Koc03!#] compare the efficiency of several types of angular quadratures. They recommend the quadrature for its better accuracy. However calculations performed with the quadrature satisfy a good compromise between accuracy and rapidity as shown in [#!Stanford!#], and may also be used.