http://dx.doi.org/10.1186/1758-2946-3-32

Has a 3D Tanimoto score with the counterpart molecule where the 3D shape similarity for the two is greater than 0.795 and the 3D feature score is greater than 0.495 or there are no features and the 3D shape similarity is greater than 0.925, where the shape similarity ST is calculated by ST=VAB/(VAA+VBB-VAB), where VAA and VBB are self-overlap volume of conformers A and B, and VAB is the common overlap volume between them and the feature score CT is calculated by CT=sum(VfAB)/(sum(VfAA)+sum(VfBB)-sum(VfAB)), where the superscript f indicates any of the six independent fictitious feature atom types, VfAA and VfBB are the respective self-overlap volumes of conformers A and B for feature atom type f, and VfAB is the overlap volume of conformers A and B for feature type f.