doc-en/par-lignedeniveau-en.tex

   1 \section{Lines of \Index{intersecting planes}}
   2
   3 For every object of the type \Lcs{psSolid}, it is possible to draw the lines
   4 of intersection between a chosen solid and one or more planes.
   5
   6 The numeric argument \texttt{\Lkeyword{intersectiontype}=$k$} (value $-1$ by default)
   7 determines whether or not to draw the intersection lines. Set to $0$, the
   8 intersection lines are drawn.
   9
  10 There are three keys to be handled:
  11
  12 \begin{itemize}
  13
  14 \item \texttt{\Lkeyword{intersectionplan}=\{[$eq_1$] ... [$eq_n$]\}}
  15 defines a list of the equations $eq_i$ of the intersecting planes. The $eq_i$
  16 could as well be some objects from the type \Lkeyword{plan} (see the related section).
  17 \begin{equation*}
  18   ax+by+cz+d=0    \qquad \text{that would deliver $[a\, b\, c\, d\,]$ as one of the $n$ equations}
  19 \end{equation*}
  20
  21 \item \texttt{\Lkeyword{intersectionlinewidth}=$w_1$ ... $w_n$}
  22 defines a list of the thickness in picas $w_i$ for each of the intersection lines.
  23
  24 \item \texttt{\Lkeyword{intersectioncolor}=color$_1$ ... color$_n$}
  25 defines a list for the colors of the intersection lines.
  26
  27 \end{itemize}
  28
  29 \begin{LTXexample}[width=6cm]
  30 \psset{lightsrc=20 -20 10,viewpoint=50 -20 10 rtp2xyz,Decran=50}
  31 \psset{unit=0.5}
  32 \begin{pspicture*}(-5,-4)(5,5)
  33 \psSolid[object=cube,
  34    intersectiontype=0,
  35    intersectionplan={[1 0 .5 2] [1 0 .5 -1]},
  36    intersectionlinewidth=1 2,
  37    intersectioncolor=(bleu) (rouge),
  38    RotX=20,RotY=90,RotZ=30,
  39    a=6,
  40    action=draw*]
  41 \end{pspicture*}
  42 \end{LTXexample}
  43
  44 \endinput