Improving the generation or a 3D vessel model of a region ot interest of an object includes: acquiring image data of the region of interest comprising picture elements and embodying multiple predetermined features; deriving, for ones of the picture elements, respective probability values; displaying, for interaction purposes, ones from among the probability values such that a plurality from among the features are in the displayed values; designating a feature; deciding, based on the designation, what constitutes, from among the multiple predetermined features, the closest relevant predetermined feature; and calculating, to thereby generate, object data on behalf of what was decided to be the closest relevant predetermined feature.