def _apply_cen_to_throats(self, p_cen, t_cen, t_norm, men_cen):
        r'''
        Take the pore center and throat center and work out which way
        the throat normal is pointing relative to the vector between centers.
        Offset the meniscus center along the throat vector in the correct
        direction
        '''
        v = p_cen - t_cen
        sign = np.sign(np.sum(v*t_norm, axis=1))
        c3 = np.vstack((men_cen*sign,
                        men_cen*sign,
                        men_cen*sign)).T
        coords = t_cen + c3*t_norm
        return coords
r'''
        Take the pore center and throat center and work out which way
        the throat normal is pointing relative to the vector between centers.
        Offset the meniscus center along the throat vector in the correct
        direction