\section{Drawing a \Index{line}}

This command is adapted from the macro \verb+\pstThreeDLine+ from the package
\texttt{pst-3dplot} of Herbert \textsc{Voss}%
\footnote{\url{http://tug.ctan.org/tex-archive/graphics/pstricks/contrib/pst-3dplot}.}

We use \texttt{\textbackslash psLineIIID[options](x0,y0,z0)(x1,y1,z1)\ldots(xn,yn,zn)},
with the following possible options:
\begin{itemize}
  \item \texttt{\Lkeyword{linecolor}=colour};
  \item \texttt{\Lkeyword{doubleline}=true};
  \item \texttt{\Lkeyword{linearc}=value}.
\end{itemize}
It is not possible to put arrowheads at the ends of the lines.

\begin{LTXexample}[width=6.5cm]
\psset{viewpoint=50 20 30 rtp2xyz,Decran=50}
\begin{pspicture}(-3,-4)(4,4)
\psSolid[object=cube,a=4,action=draw*,
  fillcolor=magenta!20]%
\psLineIIID[linecolor=blue,
  linewidth=0.1,linearc=0.5,
  doubleline=true](-2,-2,-2)(2,2,2)(2,2,-2)(2,-2,0)
\psPoint(2,-2,0){A}\psPoint(-2,-2,-2){B}
\psPoint(2,2,2){C}\psPoint(2,2,-2){D}
\psdot[dotsize=0.2](A)\psdot[dotsize=0.2](B)
\psdot[dotsize=0.2](C)\psdot[dotsize=0.2](D)
\psLineIIID[linecolor=green]%
  (-2,-2,-2)(2,2,2)(2,2,-2)(2,-2,0)
\psPolygonIIID[linecolor=red,
  fillstyle=vlines,linearc=0.5,
  linewidth=0.1](-2,-2,2)(-2,2,2)(2,2,2)(2,-2,2)
\axesIIID(2,2,2)(4,4,4)
\end{pspicture}
\end{LTXexample}


\endinput
