All electrical motor designers know that the computation of cogging torque is a tricky task in 3D. Indeed, the amplitude of this quantity is almost the same as the numerical noise. In most cases, a classical meshing methodology is not sufficient and specific methodology must be used. At CEDRAT, the application team, thanks to its experience has developed methodologies to successfully compute cogging torque in most of cases. This article presents a specific meshing methodology to compute cogging torque for 2D and 3D radial electrical machine. It begins with some general recommendation concerning the definition of the geometry in order to facilitate the meshing operation. Then, it presents the specific meshing methodology applied to a 2D SPM motor and to a 3D IPM motor.