[pstricks] Fwd: PSTricks code -- pst-solides3d

[Herbert Voss]

About my job, I need to use LaTeX and PSTricks. For this, I am writing 
some articles about conic sections with PSTricks images. I would like 
insert some figure like this (see attachment 1 - ellisse1) that I 
create; however I would like to improve the image in this order: 1) hide 
the cone above section plan (for example with another colour) or 2) use 
- in the PSTricks code - the object=load in order to have the image like 
the second attachment (see parabola3 for example): I would like have a 
mix of the two images, i.e. a rotation of the cone above the 
intersection plan like in this image.
I am not able to do this; I am not able to write the right code. Could 
you help me? For all your advices I will thanks you.
Here is my code (for the attachment 1):

\documentclass[11pt]{article}
\usepackage{pst-solides3d}
\usepackage{pstricks-add}
\begin{document}
\psset{unit=2.0}
\begin{pspicture}(-2,-2)(2,2)
\psset[pst-solides3d]{viewpoint=25 16 10 
rtp2xyz,Decran=20,lightsrc=viewpoint}
\defFunction[algebraic]{iperbole}(r,theta){r*cos(theta)}{r*sin(theta)}{r}
\psSolid[object=surfaceparametree,
          base=-3 3 pi neg pi,hue=0.2 0.5,
          function=iperbole,
          linewidth=0.1pt,ngrid=0.1,
          intersectionplan={[0 0.5 1 1]}, name=XYZ,opacity=0.5]
\psSolid[object=plan,definition=equation,
          args={[0 0.5 1 1]},fillcolor=yellow!20,
          base=-3.0 3.0 -3.0 3.5,ngrid=20 20,linewidth=0.01,
          action=draw,name=Plane,opacity=0.5]
\psSolid[object=fusion,base=XYZ Plane_s,opacity=0.5]
\axesIIID[linecolor=blue](0,0,2.8)(8.5,4.5,4)
\psset{object=courbe,r=0,linecolor=red,linewidth=0.03,
        resolution=360,function=Fxy}
\defFunction[algebraic]{Fxy}(y){y}{sqrt(-0.75*(y)^2+(y)+1)}{-0.5*y-1}
\psSolid[range=-0.6666 2,RotZ=90]
\psset{object=courbe,r=0,linecolor=red,linewidth=0.03,
        resolution=360,function=Fxy}
\defFunction[algebraic]{Fxy}(y){y}{-sqrt(-0.75*(y)^2+(y)+1)}{-0.5*y-1}
\psSolid[range=-0.6666 2,RotZ=90]
\rput[bl](2.0,-0.9){\textit{piano di sezione} $\pi$}
\rput[bl](-1.81,-3.2){\textit{cono} $\Gamma$}
\end{pspicture}
\end{document}

Best regards
Carlo Alberini
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