This data item defines a polynomial in space if 2D or 3D. Other data items can check if nodes are located on this geometry. In 2D it is the curve . In 3D it is the surface . In 2D defines the domain of . In 3D defines the domain of and defines the domain of . All node with a distance (that is the -distance in 2D or the -distance in 3D) not more than tolerance are considered to be part of the polynomial.