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<div> <font color="black" face="Arial, Helvetica, sans-serif" size="2"><pre style="font-size: 9pt;"><tt>Leon Free Wrote :<br>

>i want to obtain the same result when the vertical plane P need not be
>parallel to one of the axis, ie P={(x,y,z) : ax+by+c=0} with a,b both
>nonzero (and (obivously) has a non empty intersection with the surface)</tt></pre></font><br>

A first draft. Uncomment the following lines to write the files. dat<br>

<br>

\documentclass{article}<br>

\usepackage[dvipsnames,svgnames]{xcolor}<br>

\usepackage{pst-solides3d}<br>

\begin{document}<br>

\begin{center}<br>

%\codejps{<br>

%/biface false def<br>

%-.5 3 0.85 3.5 [0.2 0.2]<br>

%{/y exch def<br>

% /x exch def<br>

% -0.35 x dup mul mul<br>

%  y 2 sub y 1.5 sub mul sub<br>

%  0.2 x mul y mul add<br>

%  4.5 add }<br>

%  true<br>

%  newsurfaceparametree<br>

%(Surface) writesolidfile<br>

% }<br>

 \begin{pspicture}(-4,-4)(7,10)<br>

 \psset{lightsrc=viewpoint,viewpoint=100 35 30 rtp2xyz,Decran=150}<br>

%\psset{solidmemory}<br>

%\psSolid[object=datfile,<br>

%   file=Surface,<br>

%   plansepare={[0.707 0.707 0 -2.5]},<br>

%   name=surface,<br>

%   action=none]<br>

%\psSolid[object=load,<br>

%  load=surface1,<br>

%   file=surface1,action=writesolid]<br>

%\psSolid[object=load,<br>

%   load=surface0,<br>

%   file=surface0,action=writesolid]<br>

\axesIIID(0,0,0)(5,5,7)<br>

\psSolid[object=datfile,<br>

         hollow,<br>

         rm=0,<br>

         file=surface1]<br>

\psSolid[object=plan,<br>

          definition=equation, args={[0.707 0.707 0 -2.5] },opacity=.5,<br>

          plangrid,<br>

          fillcolor=ForestGreen!20, linecolor=gray!50,base=-6 0 -6 0]<br>

\psSolid[object=datfile,<br>

         hollow,<br>

         rm=0,<br>

         intersectiontype=0,<br>

         intersectionplan={ [0.707 0.707 0 -2.51] },intersectioncolor=(rouge),<br>

         intersectionlinewidth=2,<br>

         file=surface0](0,0,0)<br>

      \end{pspicture}<br>

\end{center}<br>

\end{document}<br>

<br>

<br>

ML<br>


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