'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. The first is using predefined point names and the second is by specifying the coordinates explicitly. When the coordinates are defined, then the parameter ''COMPACT'' must be used as shown above but when point names are used, then ''COMPACT'' must be omitted. CAD-interfaces might use this functionality.