\documentclass[a4paper]{article} \usepackage{pst-solides3d} \begin{document} \pagestyle {empty} \begin{pspicture}(-4,-4.5)(4,4.5) \psset{viewpoint=50 20 30 rtp2xyz,lightsrc=viewpoint} \psset{solidmemory} \psset[pst-solides3d]{color1=red!60} \psset[pst-solides3d]{color2=red!20} \psSurface[ngrid=.25 .25,inouthue=1 0 0.5 1, linewidth=0.5\pslinewidth,axesboxed, tablez=-.5 .5, zcolor=(Red) (Yellow), algebraic](-4,-4)(4,4){% ((y^2)-(x^2))/4 } \end{pspicture} \end{document}