Patent ID: 6906731

Claim:
A method of analyzing an object data set comprising points in a multi-dimensional space, in which data set a tubular structure occurs, said method comprising the steps of: a) choosing a position related to the tubular structure; b) determining the multi-dimensional co-ordinates of a starting position associated with said screen position; c) deriving a plane through said starting position having its normal directed to the tubular structure; d) determining a surface point of the tubular structure as a target position associated with the starting position; e) selecting a number of points forming part of the surface of the tubular structure in the vicinity of the target position; f) determining the surface point in the selection which is closest to the plane; and g) using the surface point determined in the step f) as a new starting position: wherein the step (f) also comprises the steps of: 1) projecting the selected surface points on the plane; 2) defining a sub-selection which includes selected surface points whose projection on the plane lies at a distance from the starting position which is equal to or less than a certain ceiling value; and 3) selecting from the sub selection the first surface point having the smallest distance to the plane.