Several terrestrial planets and their moons in the Solar System now have external gravity field models, usually expressed in terms of spherical harmonic basis functions, based on tracking the perturbations of the orbits of artificial satellites. Due to the attenuation of gravitation with altitude above the attracting body, these are inevitably limited in spectral and thus spatial resolution. Newtonian forward modelling of high-pass-filtered topography (higher than the spherical harmonic degree of the gravity model) adds finer detail down to the resolution of the topographic model, though under the assumption that the near-surface topographic bulk density is constant. This contribution will summarise: 1) such models of the Earth, Moon and Mars (produced by the author’s team) and Venus (produced by others and based on our methods); 2) a band-filtering technique that can enhance the detection of hitherto-unknown features on the Moon (Featherstone et al. 2013, JGR-P, doi: 10.1002/jgre.20101), which can be applied to other terrestrial planets and their moons in the Solar System; and 3) the limitations of these techniques, particularly the assumption of a constant bulk-density and how this might be overcome.