A NurbsSurfaceMesh is a kind of Geometry. You can navigate the NurbsSurfaceMesh using the generic objects such as Facet, Point and Sample or you can navigate using objects that are specific to the NurbsSurfaceMesh such as NurbsSurface, ControlPoint and NurbsSample.

VBScript Example

set oObject = Application.ActiveProject.ActiveScene.Root.AddGeometry("Sphere","NurbsSurface")
set oNurbsSurfaceMesh = oObject.ActivePrimitive.Geometry

Primitive.Geometry X3DObject.AddNurbsSurfaceMesh X3DObject.AddNurbsSurface