'nurs' [<name(char9)>|'!' ['DEFINE' ['COMPACT'] <u.deg> <v.deg> -> <u.npnt> <v.npnt> <u.nknt> <v.nknt>]| ['CONTROL' <u.index> <v.index> [<pnt>|<x y z>] -> <weight>]| ['KNOT' <U>|<V> <index> <value>]| ['END']] | [ <!> <setname(containing surfaces)>]This keyword is used to define a nurbs shape. Surfaces might use nurbs to define the interior geometry. There are two possible ways of definition. Either by using predefined point-names or by specifying the coordinates explicitly. When the coordinates are defined then the parameter ``COMPACT'' must be used as shown above but when the point names are used then this parameter must be omitted. CAD-interfaces might use this functionality.