Appeal No. 2002-1491
Application 08/845,526
requires implementing a de Casteljau process in the graphics pipeline, evaluating a Bezier curve
or surface using the de Casteljau process, implementing the de Casteljau process using a tri-
linear interpolator in the graphics pipeline, and rendering the Bezier curve or surface without
first converting the Bezier curve or surface to a polygon mesh.
The examiner cites to the Luken reference for its disclosure of a graphics rendering
pipeline using a de Casteljau process to evaluate a b-spline curve in NURBS form. It is
acknowledged by the examiner that Luken does not teach using the graphics pipeline to evaluate
a Bezier curve or surface as is required by claim 9 (Answer at page 10). Nonetheless, the
examiner cites to the Jia reference to make up for that deficiency. As discussed above, however,
the Jia reference does not disclose the “rendering” of any computer graphics. Instead, it is
directed to computerized numerical control of the motions of a machine tool. The examiner has
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. Although Jia discloses conversion of NURBS defined curves to a
Bezier model, the examiner has not articulated a reasonable motivation for one with ordinary
skill in the art to implement that conversion for use within a graphics rendering pipeline,
9
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