A new method is presented to assist the clinician in planning a interventional procedure while the patient is already on the catheterization table. Based on several ECG-selected projections from a rotational X-ray acquisition, both a volumetric cone-beam reconstruction of the coronary tree as well as a three-dimensional surface model of the vessel segment of interest are generated. The proposed method provides the clinician with the length and diameters of the vessel segment of interest as well as with an ’optimal working view’. In this view, the gantry is positioned such that the vessel segment of interest is the least foreshortened and vessel overlap is minimized during the entire heart cycle. Examples on a phantom object and on patient data demonstrate the accuracy and feasibility of the approach.