These examples demonstrate how to create NURBS surfaces in CUBIT. 

dem - Example of creating a topographic surface using a grid of spline
    curves.

merge_surfs - Merge primitive geometry to create sheet body made up of
    multiple planar segments.

subduction - Example of creating a 3-D mesh of a subduction zone with
  topography/bathymetry and multiple nonplanar faults (subduction +
  splay).

triangles - Example of creating a NURBS surface from a triangulated
    surface in Facets format.

