Scoring functions can be markedly improved by taking into account the status environs of ligand rings (or indeed other bulky rigid ligand structures) on the ligand when the ligand is complexed with the receptor. In its most general form, the invention features, quantifying a particular component of binding affinity between a ligand and a receptor molecule. Specifically, the component in question takes into account the spatial relationship between ligand ring structure(s) (or bulky rigid ligand structures) and their ambient surroundings when the ligand is bound to the receptor molecule. The method steps may be used when quantifying a component that reflects these particular ligand features alone, or the steps may be part of a comprehensive method of quantifying binding affinity which includes numerous other factors that relate to binding affinity in addition to the component. For example, one may calculate an initial binding affinity and then adjust the initial binding affinity by a factor obtained at least in part based on the classification of the ring structure.