public PolyhedronBoxTree(Polyhedron_3<Point_3> poly) {
   distanceMin = new Double(1e15);
   boundingBox = new double[3][2]; // coordonn�e, puis min et max
   cutDim = 0;
   this.poly = poly;
   facets = poly.facets;
   this.nFacets = facets.size();
   computeBoundingBox();
   if (nFacets > 1) computeTree();
 }