  Modelling gravity is a fundamental problem that must be tackled in N-body
simulations of stellar systems, and satisfactory solutions require a deep
understanding of the dynamical effects of softening. In a previous paper (Romeo
1997), we have devised a method for exploring such effects, and we have focused
on two applications that reveal the dynamical differences between the most
representative types of softened gravity. In the present paper we show that our
method can be applied in another, more fruitful, way: for developing new ideas
about softening. Indeed, it opens a direct route to the discovery of optimal
types of softened gravity for given dynamical requirements, and thus to the
accomplishment of a physically consistent modelling of disc galaxies, even in
the presence of a cold interstellar gaseous component and in situations that
demand anisotropic resolution.
