anim.tex

%@AUTEUR: Juergen Gilg
\documentclass{article}
\usepackage[dvipsnames,svgnames]{pstricks}
\usepackage{pst-node,pst-plot,pst-eucl}
\usepackage{graphicx}
\usepackage{pst-solides3d}
\usepackage{multido}
\usepackage[nomessages]{fp}
\pagestyle{empty}
\begin{document}
\psset{SphericalCoor,viewpoint=50 50 30,lightsrc=25 37 17,Decran=50,unit=0.75}
\begin{center}
\def\voc{%
\pstVerb{
 /torsion {
2 dict begin
/M defpoint3d % on r\'{e}cup\`{e}re les coordonn\'{e}es
/AngleTorsion M \ai\space mul neg 3 -2 roll pop pop def
M 0 0 AngleTorsion rotateOpoint3d
end} def
}%
 
 
\defFunction{F}(t){t cos 5 mul}{t sin 5 mul}{}
\defFunction{G}(t){t 36 add cos 3 mul}{t 36 add sin 3 mul}{}
 
\rput(0,0){\psSolid[%
    object=ruban,
    h=7.5,
    fillcolor=gray,
    incolor=lightgray,
    base=0 72 360 {/Angle exch def Angle F Angle G} for,
    transform=torsion,
    ngrid=12
    ](0,0,0)
}
}
 
\FPdiv{\myDeltaA}{6}{60}%
\def\ai{0}%
\FPdiv{\myDeltaB}{0.95}{90}%
\def\bi{0.5}%
\multido{\i=1+1}{60}{% 
 \begin{pspicture}(-4,0)(4,9)
  \voc%
 \end{pspicture}
 \newpage
 \FPadd{\ai}{\ai}{\myDeltaA}
 \FPadd{\bi}{\bi}{\myDeltaB}
}
\end{center}
 
\end{document}