hypocycloide.tex

\documentclass{article}
\usepackage{pst-solides3d}
\begin{document}
\begin{pspicture}(-3.5,-4)(3.5,4)
\psset{SphericalCoor=true,viewpoint=100 20 45,Decran=75}
\psSolid[object=grille,base=-5 5 -5 5]%
\defFunction[algebraic]{F}(t){4*cos(t)+cos(4*t)/2}{4*sin(t)-sin(4*t)/2}{1}
\defFunction[algebraic]{F'}(t){-4*sin(t)-2*sin(4*t)}{4*cos(t)-2*cos(4*t)}{0}
\defFunction[algebraic]{F''}(t){-4*cos(t)-8*cos(4*t)}{-4*sin(t)+8*sin(4*t)}{0}
\psSolid[object=courbe,
   range=0 Pi 2 mul,
   ngrid=90 16,
   function=F,
   r=1]
\end{pspicture}
\end{document}