\documentclass{article} \usepackage{pst-solides3d} \begin{document} \pagestyle{empty} \psset{unit=0.5,lightsrc=50 -50 50,viewpoint=100 0 0 rtp2xyz,Decran=110,linewidth=0.5\pslinewidth} \begin{pspicture}(-5,-6)(5,6) \defFunction{F}(t){t cos dup mul 5 mul}{t cos t sin mul 5 mul}{t sin 5 mul} \codejps{% /cylindre1 { -5 2.5 5 [36 36] newcylindre {2.5 0 0 translatepoint3d} solidtransform dup (White) outputcolors } def /sphere1 { 5 [36 72] newsphere dup (White) outputcolors } def /CS {cylindre1 sphere1 solidfuz} def CS drawsolid**} \psPoint(0,0,0){O} \psSolid[object=courbe,r=0, function=F, range=0 360, linecolor=red,linewidth=4\pslinewidth] \end{pspicture} \end {document}