trompette.tex

\documentclass{article}
\usepackage[dvipsnames,svgnames]{pstricks}
\usepackage{pst-solides3d}
 
\begin{document}
\pagestyle{empty}
 
\begin{pspicture}(-6,-8)(6,6)
\psframe*[linecolor=gray!50](-6,-8)(6,6)
\psset[pst-solides3d]{viewpoint=20 40 30 rtp2xyz,Decran=20,lightsrc=10 15 10}
\defFunction[algebraic]{trompette}(u,v)
   {cos(u)*sin(v)}
   {cos(v)+ln(tan(1/2*v))+2}
   {sin(u)*sin(v)}
%% % en notation RPN
%% \defFunction{trompette}(u,v)
%%    {u Cos v Sin mul}
%%    {v Cos 0.5 v mul Tan log 2.3 mul add}
%%    {u Sin v Sin mul}
\psSolid[object=grille,base=-4 4 -4 4,action=draw*,linecolor=red](0,0,-2)
\psSolid[object=surfaceparametree,linecolor={[cmyk]{1,0,1,0.5}},
   base=0 2 pi mul 0.03 2,fillcolor=yellow!50,incolor=green!50,
   function=trompette,linewidth=0.5\pslinewidth,unit=2,
   ngrid=20]%
\gridIIID[Zmin=-2,Zmax=2](-4,4)(-4,4)
\end{pspicture}
 
\end{document}