test_32.tex

\documentclass[a4paper]{article}
\usepackage{pst-solides3d}
\pagestyle{empty}
\begin{document}
 
%@AUTEUR: Juergen Gilg
 
\psset{unit=0.55}
\psset{viewpoint=10 -10 10,
   lightsrc=8 -10 6,
   Decran=35}
\begin{pspicture}(-5,-5)(6,9)
\pstVerb{
/gro {
4 dict begin
   /M defpoint3d
   /a 0.5 def
   /b 1 a 3 sqrt mul sub def
   /k M norme3d a mul b add def
   M k mulv3d
end
} def
}
\psset{action=draw**,linewidth=.02,linecolor=lightgray}
\psSolid[object=cube,
      fillcolor=gray,
      r=2,
      transform=gro,
      ngrid=24,
      ](0,0,0)
\end{pspicture}
 
\end{document}