Appeal No. 2002-1491
Application 08/845,526
not shown that Jia’s system includes a graphics rendering pipeline or even has a need for one.
While Jia’s computerized numerical control system does convert a NURBS defined curve or
surface to a Bezier curve for purposes of controlling the movements of a machine tool, the
examiner has not shown why one with ordinary skill in the art would have applied that teaching
to a graphics rendering pipeline. While the examiner states that according to Jia the Bezier curve
is a special case of the B-spline curve, the transformation into Bezier curves still requires
specially chosen parameters. Also, the fact that the de Casteljau process can be used to evaluate
Bezier curves does not mean the NURBS representation of a curve and the Bezier model of the
same are equivalents.
With regard to the examiner’s comment about the Luken reference, contained in the
response to arguments portion of the examiner’s Answer, note our earlier discussion on that
subject in the context of our discussion of the rejection of claims 9 and 12.
For the foregoing reasons, the rejection of claims 16, 18 and 19 is reversed.
E. The Rejection of Claims 20-24 for
Obviousness over Luken and Gharachorloo
Claims 21-24 depend directly or indirectly from independent claim 20. Claim 20 recites
a method of using a graphics rendering pipeline to “render a curve or surface directly from a
NURBS (non-uniform rational B-spline) model.” The method includes the steps of (a)
performing a global to local transformation on a NURBS model using the graphics rendering
pipeline; (b) evaluating a plurality of NURBS control points using tri-linear interpolation in the
graphics rendering pipeline to obtain a plurality of points on a curve or surface defined by the
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