Ex parte Latham

Board of Patent Appeals and Interferences

Jun 22, 2000

08307028 (B.P.A.I. Jun. 22, 2000)

THIS OPINION WAS NOT WRITTEN FOR PUBLICATION
The opinion in support of the decision being entered today (1) was not written for
publication in a law journal and (2) is not binding precedent of the Board.
Paper No. 25
UNITED STATES PATENT AND TRADEMARK OFFICE
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BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
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Ex parte ROY W. LATHAM
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Appeal No. 1998-0426
Application No. 08/307,028
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ON BRIEF
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Before JERRY SMITH, BARRETT, and DIXON, Administrative Patent Judges.
DIXON, Administrative Patent Judge.
DECISION ON APPEAL
This is a decision on appeal from the examiner's non-final rejection of claims
1-5, which are all of the claims pending in this application.
We REVERSE.
Appeal No. 1998-0426
Application No. 08/307,028
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BACKGROUND
The appellant's invention relates to a computer-implemented method of rendering
an image of smoke. An understanding of the invention can be derived from a reading of
exemplary claim 1, which is reproduced below.
1. A computer-implemented method of rendering an image of smoke or clouds in an
image generator for display of pixels on a display device, said method comprising the
steps of:
modeling the smoke as a sphere having nonuniform smoke density, and that
is comprised of a center point in three-dimensional model space, a radius,
and set of parameters defining its nonuniform density and color;
transforming the center point to screen coordinates;
transforming the radius to a screen coordinate radius;
generating a bounding polygon that surrounds a projection of the sphere in
screen coordinates;
clipping the bounding polygon to boundaries of the display device; and
for each pixel in the image, rendering a smoke effect by:
testing if the pixel is within the bounding polygon;
computing an equivalent translucency factor for the smoke at the pixel
based upon location of the pixel with respect to the transformed
center point, the screen coordinate radius, the set of parameters
defining its nonuniform density and color, and penetration depth
through the smoke; and
computing the smoke effect for the pixel based upon the equivalent
translucency factor.
Appeal No. 1998-0426
Application No. 08/307,028
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The prior art references of record relied upon by the examiner in rejecting the
appealed claims are:
Sakas et al. “Sampling and Anti-Aliasing of Discrete 3-D Volume Density
Textures”, Computers & Graphics: Eurographics '91 Award Paper, pgs.
121-134, published by Pergamon Press (1992).
Gardner, “Visual Simulation of Clouds,” Computer Graphics, Vol. 19, No. 3,
pgs. 297-303, (July 1985).
Claims 1-5 stand rejected under 35 U.S.C. § 103 as being unpatentable over
Gardner in view of Sakas.
Rather than reiterate the conflicting viewpoints advanced by the examiner and the
appellant regarding the above-noted rejections, we make reference to the examiner's
answer (Paper No. 24, mailed Aug. 28, 1997) for the examiner's reasoning in support of
the rejections, and to the appellant's brief (Paper No. 23, filed June 16, 1997) for the
appellant's arguments thereagainst.
OPINION
In reaching our decision in this appeal, we have given careful consideration to the
appellant's specification and claims, to the applied prior art references, and to the
respective positions articulated by the appellant and the examiner. As a consequence of
our review, we make the determinations which follow.
Appellant argues that Gardner does not disclose the use of a sphere in the
simulation of the clouds. Rather Gardner uses ellipsoidal surfaces with texturing applied
Appeal No. 1998-0426
Application No. 08/307,028
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only to the surface. We agree with appellant. (See brief at pages 3-6.) The examiner
rationalizes that “the ellipsoid is a sphere.” (See answer at page 4.) While we agree with
the examiner's rationalization of the similarity of the sphere and the ellipsoid, we do not
agree that a skilled artisan would have recognized them as the same. Appellant has
argued that the sphere was selected “to reduce the calculations
. . . when one is within the spheres.” (See brief at page 4.) The examiner has not set forth
a motivation for changing the ellipsoids of Gardner to spheres and to use the solid sphere
rather than merely the surface as taught by Gardner.
Appellant further argues that Gardner does not disclose a "method that models a
cloud using spheres with each sphere having a varying density of obscuring material
(corresponding to a set of parameters defining the nonuniform density and color of the
smoke or cloud)." (See brief at page 5.) We agree with appellant that Gardner does not
disclose "computing an equivalent translucency factor for the smoke at the pixel based
upon location of the pixel with respect to the transformed center point, the screen
coordinate radius, the set of parameters defining its nonuniform density and color, and
penetration depth through the smoke" as recited in claim 1.
Appellant generally argues that Gardner is merely concerned with modeling the
surface of an ellipsoidal surface which does not have volume or depth beyond the
Appeal No. 1998-0426
Application No. 08/307,028
5
displayed surface generated. (See brief at page 4.) We agree with appellant that the
claimed invention is directed to spherical volumes with a nonuniform density.
The examiner relies upon Sakas to teach the use of a nonuniform density function in
3-D modeling smoke and clouds. While Sakas discloses the use of 3-D models and
projection of the model onto the screen (see Sakas figure 2), Sakas does not disclose the
use of a sphere, with a center point, as the object being modeled or the computations
recited in claim 1. While Sakas does teach the use of density functions, in our view, Sakas
does not remedy the above deficiencies in Gardner. Therefore, we will not sustain the
rejection of claim 1 and dependent claims 2-5.
CONCLUSION
To summarize, the decision of the examiner to reject claims 1-5 under 35 U.S.C. §
103 is reversed.
REVERSED
JERRY SMITH )
Administrative Patent Judge )
)
)
)
) BOARD OF PATENT
LEE E. BARRETT ) APPEALS
Administrative Patent Judge ) AND
) INTERFERENCES
)
Appeal No. 1998-0426
Application No. 08/307,028
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)
)
JOSEPH L. DIXON )
Administrative Patent Judge )
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