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gensurf (1)
NAME
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gensurf - generate a RADIANCE description of a curved surface |
SYNOPSIS
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gensurf mat name 'x(s,t)' 'y(s,t)' 'z(s,t)' m n [
-e expr ][ -f file ][ -s ]
gensurf mat name 'x(s,t)' 'y(s,t)' dfile m n [ -e
expr ][ -f file ][ -s ]
gensurf mat name dfile dfile dfile m n [ -s
] |
DESCRIPTION
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Gensurf produces a RADIANCE scene description of a
functional surface defined by the parametric equations
x(s,t), y(s,t), and z(s,t). The surface normal
is defined by the right hand rule as applied to (s,t).
S will vary from 0 to 1 in steps of 1/m, and
t will vary from 0 to 1 in steps of 1/n. The
surface will be composed of 2*m*n or fewer triangles
and quadrilaterals. The expressions are of the same type
used in RADIANCE function files. Auxiliary expressions
and/or files may be specified in any number of -e and
-f options. The -s option adds smoothing
(surface normal interpolation) to the surface. |
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The second invocation form reads z data values from the file
dfile. This file must give either m*n or (m+1)*(n+1)
floating point z values. If m*n values are given, then the
values correspond to the centroid of each quadrilateral
region. If (m+1)*(n+1) values are given, then the values
correspond to the vertices of each quadrilateral region. The
ordering of the data in the file is such that the s values
are changing faster than the t values. If a minus ('-') is
given for dfile, then the values are read from the
standard input. |
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The third invocation form is used to read coordinate
triplets from a file or the standard input. The three
dfile arguments must all be the same, and the
corresponding file must contain three floating point values
for each point location. The ordering and other details are
the same as those described for z value files
above. |
EXAMPLE
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To generate a tesselated sphere: |
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gensurf crystal ball 'sin(PI*s)*cos(2*PI*t)' 'cos(PI*s)'
'sin(PI*s)*sin(2*PI*t)' 7 10 |
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To generate a 10x20 smoothed height field from 12 recorded
vertex z values: |
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gensurf dirt ground '10*s' '20*t' height.dat 2 3
-s |
AUTHOR
BUGS
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The smoothing operation requires that functions be defined
beyond the [0,1] boundaries of s and t. |
SEE ALSO
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