%% Auteur : Manuel Luque
%%
\bgroup
 \newcommand\quadrillage{%
\psSolid[object=parallelepiped,a=8,b=8,c=6,action=draw,linecolor=red,linewidth=0.5\pslinewidth]%
\psset{linecolor=red}\red
\multido{\ix=-4+1}{9}{%
     \psPoint(\ix\space,4,-3){X1}
     \psPoint(\ix\space,4 .2 add,-3){X2}
     \psline(X1)(X2)
     \uput[-120](X1){\small\ix}}
\multido{\iy=-4+1}{9}{%
     \psPoint(-4,\iy\space,-3){Y1}
     \psPoint(-4 .2 sub,\iy\space,-3){Y2}
    \psline(Y1)(Y2)
     \uput[0](Y1){\small\iy}}
\multido{\iz=-3+1}{7}{%
     \psPoint(4,4,\iz\space){Z1}
     \psPoint(4,4 .2 add,\iz\space){Z2}
     \psline(Z1)(Z2)
     \uput[l](Z1){\small\iz}}
 \psPoint(0,4 0.5 add,-3){X0}
 \uput[-120](X0){$x$}
     \psPoint(-4 .5 sub,0,-3){Y0}
 \uput[0](Y0){$y$}}

\multido{\i=0+20}{1}{%
\begin{pspicture}(-5.5,-6)(4.5,4)
\psframe*(-5.5,-6)(4.5,4)
\psset{linewidth=0.75\pslinewidth}
\psset[pst-solides3d]{viewpoint=20 120 30 rtp2xyz,Decran=15,lightsrc=-10 15 10}
\psSolid[object=grille,base=-4 4 -4 4,action=draw*,linecolor=gray](0,0,-3)
\defFunction{shellplan}(u,v)
   {1.2 v exp u Sin dup mul v Cos mul mul}
   {1.2 v exp u Sin dup mul v Sin mul mul}
   {-3}
\psSolid[object=surfaceparametree,
   base=0 pi pi 4 div neg 5 pi mul 2 div,incolor=gray,fillcolor=gray,
   function=shellplan,RotZ=\i,
   ngrid=25]%
\psSolid[object=grille,base=-4 4 -4 4,action=draw,linecolor=gray](0,0,-3)
\defFunction{shell}(u,v)
   {1.2 v exp u Sin dup mul v Cos mul mul}
   {1.2 v exp u Sin dup mul v Sin mul mul}
   {1.2 v exp u Sin u Cos mul mul}
\psSolid[object=surfaceparametree,linecolor={[cmyk]{1,0,1,0.5}},
   base=0 pi pi 4 div neg 5 pi mul 2 div,incolor=yellow!50,
   function=shell,RotZ=\i,
   ngrid=30]%
\quadrillage%
\end{pspicture}}

\egroup

\end{document}
%% Auteur : Manuel Luque
%%
\bgroup
 \newcommand\quadrillage{%
\psSolid[object=parallelepiped,a=8,b=8,c=6,action=draw,linecolor=red,linewidth=0.5\pslinewidth]%
\psset{linecolor=red}\red
\multido{\ix=-4+1}{9}{%
     \psPoint(\ix\space,4,-3){X1}
     \psPoint(\ix\space,4 .2 add,-3){X2}
     \psline(X1)(X2)
     \uput[-120](X1){\small\ix}}
\multido{\iy=-4+1}{9}{%
     \psPoint(-4,\iy\space,-3){Y1}
     \psPoint(-4 .2 sub,\iy\space,-3){Y2}
    \psline(Y1)(Y2)
     \uput[0](Y1){\small\iy}}
\multido{\iz=-3+1}{7}{%
     \psPoint(4,4,\iz\space){Z1}
     \psPoint(4,4 .2 add,\iz\space){Z2}
     \psline(Z1)(Z2)
     \uput[l](Z1){\small\iz}}
 \psPoint(0,4 0.5 add,-3){X0}
 \uput[-120](X0){$x$}
     \psPoint(-4 .5 sub,0,-3){Y0}
 \uput[0](Y0){$y$}}

\multido{\i=0+20}{1}{%
\begin{pspicture}(-5.5,-6)(4.5,4)
\psframe*(-5.5,-6)(4.5,4)
\psset{linewidth=0.75\pslinewidth}
\psset[pst-solides3d]{viewpoint=20 120 30 rtp2xyz,Decran=15,lightsrc=-10 15 10}
\psSolid[object=grille,base=-4 4 -4 4,action=draw*,linecolor=gray](0,0,-3)
\defFunction{shellplan}(u,v)
   {1.2 v exp u Sin dup mul v Cos mul mul}
   {1.2 v exp u Sin dup mul v Sin mul mul}
   {-3}
\psSolid[object=surfaceparametree,
   base=0 pi pi 4 div neg 5 pi mul 2 div,incolor=gray,fillcolor=gray,
   function=shellplan,RotZ=\i,
   ngrid=25]%
\psSolid[object=grille,base=-4 4 -4 4,action=draw,linecolor=gray](0,0,-3)
\defFunction{shell}(u,v)
   {1.2 v exp u Sin dup mul v Cos mul mul}
   {1.2 v exp u Sin dup mul v Sin mul mul}
   {1.2 v exp u Sin u Cos mul mul}
\psSolid[object=surfaceparametree,linecolor={[cmyk]{1,0,1,0.5}},
   base=0 pi pi 4 div neg 5 pi mul 2 div,incolor=yellow!50,
   function=shell,RotZ=\i,
   ngrid=30]%
\quadrillage%
\end{pspicture}}

\egroup