NURBS with trim curves

[nicholas_yue 0]

Hi,

  I have been able to create NURBS surfaces in the HDK via 

        GU_PrimNURBSurf* nurb_surface = GU_PrimNURBSurf::build(&gdp,num_rows,num_columns);
 

  I would like to add trim curves to trim the surface

   Is there any example code which illustrate associating trim curves with a NURBS surface in HDK ?

Cheers