A method of planning a surgery, the method comprising: transforming a three-dimensional segmented surface image representing at least a bony tissue cranio-facial feature of a patient, including a plurality of points P i, and having an elliptical profile in the xy-coordinate plane and a center of origin of the xy-coordinate plane to a segmented intermediate base circle surface image having the same center of origin of its xy-coordinate plane and including a plurality of points P i ' corresponding to points P i in accordance with the following equations: Px ′ = P x x b / a P y ′ = P y P z ′ = P z where Px, P y, and P z are, respectively, the x, y, and z coordinates of each point P i in the three-dimensional segmented surface image, P x ', P y ', and P z ' are respectively the x, y, and z coordinates of each corresponding point P i ' in the segmented intermediate surface image, a is a minor radius of the ellipse of the elliptical profile, and b is a major radius of the ellipse of the elliptical profile; transforming the segmented intermediate surface image to a segmented transformed surface image having a linear profile and having a plurality of points P i " corresponding to points P i and P i ' in accordance with the following equations: P x " = c x arctan P x ′ / P y ′ P y " = √ P x ′ 2 + P y ′ 2 P z " = P z ′ where P x ", P y ", and P z " are respectively the x, y, and z coordinates of each point P i " in the segmented transformed surface image, P x ', P y ', and P z ' are respectively the x, y, and z coordinates of each corresponding point P i ' in the segmented intermediate surface image, and c is the radius of the base circle; and displaying the segmented transformed surface image such that a user may, via a user input device, manipulate the segmented transformed surface image to obtain different views of the segmented transformed surface image. transforming a three-dimensional segmented surface image representing at least a bony tissue cranio-facial feature of a patient, including a plurality of points P i, and having an elliptical profile in the xy-coordinate plane and a center of origin of the xy-coordinate plane to a segmented intermediate base circle surface image having the same center of origin of its xy-coordinate plane and including a plurality of points P i ' corresponding to points P i in accordance with the following equations: Px ′ = P x x b / a P y ′ = P y P z ′ = P z where Px, P y, and P z are, respectively, the x, y, and z coordinates of each point P i in the three-dimensional segmented surface image, P x ', P y ', and P z ' are respectively the x, y, and z coordinates of each corresponding point P i ' in the segmented intermediate surface image, a is a minor radius of the ellipse of the elliptical profile, and b is a major radius of the ellipse of the elliptical profile; transforming the segmented intermediate surface image to a segmented transformed surface image having a linear profile and having a plurality of points P i " corresponding to points P i and P i ' in accordance with the following equations: P x " = c x arctan P x ′ / P y ′ P y " = √ P x ′ 2 + P y ′ 2 P z " = P z ′ where P x ", P y ", and P z " are respectively the x, y, and z coordinates of each point P i " in the segmented transformed surface image, P x ', P y ', and P z ' are respectively the x, y, and z coordinates of each corresponding point P i ' in the segmented intermediate surface image, and c is the radius of the base circle; and displaying the segmented transformed surface image such that a user may, via a user input device, manipulate the segmented transformed surface image to obtain different views of the segmented transformed surface image.