\documentclass{article} \usepackage{pst-solides3d} \begin{document} \pagestyle{empty} \begin{pspicture*}(-3,-3)(4.5,5) \psset{lightsrc=10 -20 50,viewpoint=10 -10 10,Decran=20} \defFunction{G}(t) {t} {t dup mul .25 mul} {-2} \psSolid[object=cylindre, r=1, h=1](-2,3,0) \psSolid[object=cylindre, range=-2 2, h=3, function=G, axe=0 0 1, %% valeur par défaut ngrid=3 8] \end{pspicture*} \end{document}