For every object of the type \Lcs{psSolid}, it is possible to draw the lines
of intersection between a chosen solid and one or more planes.
The numeric argument \texttt{\Lkeyword{intersectiontype}=$k$} (value $-1$ by default)
determines whether or not to draw the intersection lines. Set to $0$, the
intersection lines are drawn.
There are three keys to be handled:
\begin{itemize}
\item \texttt{\Lkeyword{intersectionplan}=\{[$eq_1$] ... [$eq_n$]\}}
defines a list of the equations $eq_i$ of the intersecting planes. The $eq_i$
could as well be some objects from the type \Lkeyword{plan} (see the related section).
\begin{equation*}
ax+by+cz+d=0 \qquad \text{that would deliver $[a\, b\, c\, d\,]$ as one of the $n$ equations}
\end{equation*}
\item \texttt{\Lkeyword{intersectionlinewidth}=$w_1$ ... $w_n$}
defines a list of the thickness in picas $w_i$ for each of the intersection lines.
\item \texttt{\Lkeyword{intersectioncolor}=color$_1$ ... color$_n$}
defines a list for the colors of the intersection lines.
