\documentclass{minimal} \usepackage{pstricks} \usepackage{pst-solides3d} \pagestyle{empty} \begin{document} \begin{pspicture}(-6,0)(4,3) \psset[pst-solides3d]{viewpoint=6 10 15,Decran=40,lightsrc=10 20 10} \defFunction{f}(x,y,z) {x} {y} { x y mul 3 x sub y sub mul } \codejps{ 0 3 0 3 [.2 dup] newgrille [1 1 0 -3] solidplansepare dup {f} solidtransform dup 0 solidrmface dup (jaune) outputcolors drawsolid** } \end{pspicture} \end{document}