Trk::PolygonCache Node1 Trk::PolygonCache + hZ + minZ + maxZ + center + nVtx + PolygonCache() Node2 std::vector< Amg::Vector3D > Node2->Node1 +vertices Node3 Vector3D Node3->Node2 +elements Node4 std::vector< std::pair < double, double > > + elements Node4->Node1 +xyVertices +edges Node5 std::vector< bool > + elements Node5->Node1 +commonVertices