%% Surface of revolution of f(y).
%               [ f(y) cos theta]
% G(y, theta) = [   y           ]
%               [ f(y) sin theta]

function [x,y,z] = sorG(paramy,theta)
x = sorf(paramy) .* cos(theta);
y =      paramy;
z = sorf(paramy) .* sin(theta);
