1. A method, comprising: determining, by a system comprising a processor, first data representing a first skeleton of a first three dimensional (3D) model; determining second data representing a second skeleton of a second 3D model; in response to determining that a number of lines of the first skeleton, for which a sample point of the first skeleton is an end point, satisfies a defined criterion, determining interposition-related global constraint data comprising an interposition-related global constraint for the sample point in accordance with weighting the sample point based on another number of other sample points that are within a polygon that connects mid-points of the lines; and determining a similarity between the first 3D model and the second 3D model based on a set of matrices corresponding to the first skeleton that comprises a matrix of the interposition-related global constraint data.