doc/info/figures/draw_parametric3.mac

   1 load("docdraw.mac");
   2
   3 docdraw3d("figures/draw_parametric3",
   4         title = "Sea shell",
   5         xu_grid = 100,
   6         yv_grid = 25,
   7         view = [100,20],
   8         surface_hide = true,
   9         parametric_surface(0.5*u*cos(u)*(cos(v)+1),
  10                 0.5*u*sin(u)*(cos(v)+1),
  11                 u*sin(v) - ((u+3)/8*%pi)^2 - 20,
  12                 u, 0, 13*%pi, v, -%pi, %pi) )$