PPT Slide
A second curve, whose basic shape is an ellipse parametrized by s (see figure), is used to generate the outer surface of the shell. The parameters a and b are the half lengths of respectively the major and minor axes of the ellipse. This curve is further rotated by and angle m about the major axis of the ellipse, by an angle W about the vertical axis, and by an angle F about a vector normal to the plane of the ellipse.