In the implementation of the MS-CG method for isotropic CG particles, several different types of basis functions of a single variable (the inter-particle separation) were tested, including discrete delta functions, linear spline basis functions, and piecewise continuous cubic polynomials. For anisotropic CG particles in the AFM-CG method, multivariate basis functions must be used as the potential depends on both the relative position and orientation of CG particles.