A surface of revolution is represented with its axis vector and generator
curve. The v parameterization is 0 to 2pi around the axis. U parameterization
is the parameterization of the generator curve. The reference vector need
not be perpendicular to the axis but must not be parallel to it. The
location of the generator curve in space defines the zero parameter value
in v. Note that this parameterization is counterintuitive with respect to
treating cylinders, cones, spheres, and torii as surfaces of revolution,
because the parameterization is flipped u for v.