Objective analysis of the quality of a stump preparation by conventional methods is complex and expensive. In this regard digitalization has created new possibilities. The high resolution of modern scanners permits visual representation of the most minute preparation parameters. Virtual rulers permit measurement of distances in many construction programs; however, the use of such measuring instruments is too time-consuming for scientific studies. The computer program presented here permits measurement of the preparation angle, calculation of the width of the preparation margin, and determination of the horizontal path of the preparation shoulder. It runs on the Windows XP operating system independently of a CAD construction program. The program analyzes datasets in the STL file format. Keywords: preparation, preclinical training, objective assessment, CAD/CAM