This shape node represents a NURBS surface based on the knot vectors and the control points that you specify. The uKnotVector and vKnotVector fields specify floating-point arrays of values; the values are the coordinates of the knot points in the surface, and you must enter them in non-decreasing order. The numUControlPoints and numVControlPoints fields specify the number of control points the surface will have in the U and V parametric directions, and will use the current coordinates that are indexed from the coordIndex field.

You can get a surface of minimum order (2) in the U or V directions by specifying two more knots than control points in that direction and having at least two control points in that direction. This surface would appear creased in one direction.

You can get a surface of maximum order (8) in the U or V directions by specifying eight more knots than control points in that direction and having at least eight control points in that direction.

The control points of the NURBS surface are transformed by the current cumulative transformation. The surface is drawn with the current light model and drawing style. The coordinates, normals, and texture coordinates of a surface are generated, so you cannot bind explicit normals or texture coordinates to a NURBS surface. The first material in the state is applied to the entire surface.

The surface is trimmed according to the currently defined profiles curves.

When default texture coordinates are applied to a NURBS surface, the edges of the texture square are stretched to fit the surface. The axes of the texture are called S and T; S is horizontal and T is vertical. The axes of the NURBS surface are called U and V; U is horizontal and V is vertical. You can also define texture coordinates explicitly with the S,T location point, the knot vectors, and the current texture coordinates.