Starting from the solar neutrino direction (see the routine MCG_GET_NEU_DIRECTION), and given the previously-chosen scattered electron energy, the cosine of the electron scattering angle is determined by the kinematics of the reaction (see Eq. 8.37 in ``Neutrino Astrophysics" by John Bahcall, Cambridge University Press, 1989). Only the azimuthal angle is picked randomly. All neutrino flavors can be simulated. See the routine DIR_ES.