\begin{ccRefFunction}{normal}

\ccFunction{Vector_3<Kernel> normal( const Point_3<Kernel>& p,  const Point_3<Kernel>& q,  const Point_3<Kernel>& r );}
 {computes the normal vector for the  vectors \ccc{q-p} and \ccc{r-p}.
 \ccPrecond The points \ccc{p}, \ccc{q}, and \ccc{r} must not be collinear.}


\end{ccRefFunction}