The feature reference point of an axis (3D straight line, cone, cylinder) is calculated from the equalized feature and the nominal geometry for a measured or a recalled feature. The starting point of the equalizing axis is selected so that a perpendicular line can be placed on the axis of the nominal geometry from the starting point of the equalizing axis and so that the perpendicular foot point is identical to the nominal geometry. The length is determined by doing the same to the end point of the axis.