A computer-implemented method for measuring a selected portion of a curved surface of an object is disclosed. The method includes the blocks of displaying a straight-line across an object, stretching the straight-line to form a plane, determining intersection points between the plane and the curved surface of the object, determining a vertical point of each point-cloud around the straight-line on the curved surface, a corresponding vertical distance, and a corresponding normal vector, projecting the vertical points onto the plane vertically, determining measured points, up tolerance points, and down tolerance points for the point-clouds around the straight-line on the plane, connecting the corresponding points to lines, and determining if one or more the dimensions of a selected portion around the straight-line of the object is acceptable according to the connected lines.