\begin{ccRefClass}{Kdtree_Interface} {\cgal} contains a default implementation for the Kdtree\_d traits class, that may be applied to any standard class of point provided by \cgal. The default traits class \ccStyle{Kdtree_Interface} is templated with a parameter \ccStyle{Point}, which is required to supply the following methods: \begin{itemize} \item Constructor, and copy constructor. \item \ccStyle{int dimension();} - return the dimension of the point. \item \ccStyle{operator[](int dim);} - an operator for accessing the various coordinates of the given point. Used also to copy coordinates between points. \end{itemize} There are two other default traits classes \ccStyle{Kdtree_Interface_2d} and \ccStyle{Kdtree_Interface_3d} which should be used when using 2D and 3D points from the {\cgal} kernel. This is done since the points in the kernel do not support changing their coordinates through direct access. \end{ccRefClass}