cone-dir_02.tex

\documentclass{article}
\usepackage{pst-solides3d}
\begin{document}
\pagestyle{empty}
 
\begin{center}
\begin{pspicture*}(-6,-6)(6,6)
\psset{solidmemory}
\psset{lightsrc=viewpoint,viewpoint=40 -60 15,Decran=60,opacity=.7}
\defFunction{G}(t)
   {t Cos t Cos mul 3 mul}
   {t Cos t Sin mul 3 mul}
   {t Sin 3 mul}
\defFunction{G'}(t)
   {t Cos t Sin mul -6 mul}
   {t 2 mul Sin -2 mul}
   {t Cos 3 mul}
\psSolid[object=cone,
   function=G,
   range=-6.28 0,
   ngrid=10 100,
   origine=-3 0 0,
   action=none,
   name=C1,
]
\psSolid[object=courbe,
   function=G,
   r=0.05,
   range=-6.28 0,
   ngrid=300 8,
   name=C2,
   fillcolor=blue,
   action=none
]
\psSolid[object=fusion,
  linewidth=.01,
  base=C1 C2,
]
\composeSolid
\end{pspicture*}
\end{center}
 
\end{document}