<html><head></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">Thanks, Herbert. &nbsp;<div>I hope that my inclusion of the picture doesn't make this too large to post (I am not so adept at posting a picture on my web page).</div><div><br></div><div>This eliminates the \psset{plan=??}, and (after some fiddling) I managed to get the two planes intersecting properly. &nbsp;However, while the first projected curve (blue) shows up fine, the second (red) does not. &nbsp;This is true even if I comment out all references to the first (blue) plane and the curve on it. &nbsp;I thought that maybe it was projecting on the "back side" of the red plane, but it fails to appear whether I rotate it 180 degrees or not.<div><br></div><div>Modified code:</div><div>*********************************</div><div><div>\documentclass[11pt]{article}</div><div>\usepackage{pst-solides3d}</div><div><br></div><div>\begin{document}</div><div>\begin{pspicture}(-3,-1.5)(3,5.5)</div><div><span class="Apple-tab-span" style="white-space:pre">        </span>\psset{unit=0.35,lightsrc=40 50 50,viewpoint=18 65 30 rtp2xyz,solidmemory}</div><div><span class="Apple-tab-span" style="white-space:pre">                </span></div><div><span class="Apple-tab-span" style="white-space:pre">        </span>\psSolid[object=plan,</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>definition=equation,</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>args={[1 0 0 0] 90},</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>base=-2 2 -0.5 4.5,</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>fillcolor=blue!10,</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>name=xplane,</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>ngrid=10 10,</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>action=none</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>]</div><div><span class="Apple-tab-span" style="white-space:pre">        </span>\psSolid[object=plan,</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>definition=equation,</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>args={[0 1 0 0] 180},</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>base=-2 2 -0.5 4.5,</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>fillcolor=red!10,</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>name=yplane,</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>ngrid=10 10,</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>action=none</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>]</div><div><span class="Apple-tab-span" style="white-space:pre">        </span>\psSolid[object=fusion,</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>base=xplane_s yplane_s,</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>opacity=0,</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>]</div><div><span class="Apple-tab-span" style="white-space:pre">        </span>\composeSolid%</div><div><span class="Apple-tab-span" style="white-space:pre">        </span>%</div><div><span class="Apple-tab-span" style="white-space:pre">        </span>\psSolid[object=plan,</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>definition=equation,</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>args={[1 0 0 0] 90},</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>base=-2 2 -0.5 4.5,</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>name=xplane,</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>ngrid=10 10,</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>action=none,</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>opacity=0,</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>]</div><div><span class="Apple-tab-span" style="white-space:pre">        </span>\defFunction[algebraic]{xcutfcn}(y){y*y}{}{}%</div><div><span class="Apple-tab-span" style="white-space:pre">        </span>\psProjection[object=courbe,</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>linecolor=blue,</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>linewidth=2pt,</div><div><span class="Apple-tab-span" style="white-space:pre">        </span> &nbsp; <span class="Apple-tab-span" style="white-space:pre">        </span>plan=xplane,</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>range=-2 2,</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>resolution=720,</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>function=xcutfcn,</div><div><span class="Apple-tab-span" style="white-space:pre">        </span> &nbsp; <span class="Apple-tab-span" style="white-space:pre">        </span>action=draw**,</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>opacity=0,</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>]</div><div><br></div><div><span class="Apple-tab-span" style="white-space:pre">        </span>\psSolid[object=plan,</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>definition=equation,</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>args={[0 1 0 0] 90},</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>base=-2 2 -0.5 4.5,</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>name=yplane,</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>linewidth=0.5pt,</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>ngrid=10 10,</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>action=none,</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>opacity=0,</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>]</div><div><span class="Apple-tab-span" style="white-space:pre">        </span>\defFunction[algebraic]{ycutfcn}(x){4*x*x}{}{}%</div><div><span class="Apple-tab-span" style="white-space:pre">        </span>\psProjection[object=courbe,</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>linecolor=red,</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>linewidth=2pt,</div><div><span class="Apple-tab-span" style="white-space:pre">        </span> &nbsp; <span class="Apple-tab-span" style="white-space:pre">        </span>plan=yplane,</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>range=-1 1,</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>resolution=720,</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>function=ycutfcn,</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>action=draw**,</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>opacity=0,</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>]</div><div>\end{pspicture}</div><div><br></div><div>\end{document}</div><div>*********************************************</div><div></div></div></div></body></html>