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.\" RCSid "$Id: bsdf2rad.1,v 1.4 2021/02/25 04:48:19 greg Exp $" |
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.TH BSDF2RAD 1 8/11/2017 RADIANCE |
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.SH NAME |
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bsdf2rad - create a RADIANCE visualization of a BSDF representation |
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.SH SYNOPSIS |
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.B bsdf2rad |
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[ |
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.B "\-r min max" |
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] |
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bsdf.xml |
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.br |
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or |
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.br |
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.B bsdf2rad |
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[ |
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.B "\-r min max" |
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] |
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hemi1.sir |
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[ |
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hemi2.sir .. |
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] |
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.br |
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.SH DESCRIPTION |
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.I Bsdf2rad |
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takes a bidirectional scattering distribution function (BSDF) |
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and plots it as a RADIANCE scene file. |
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In the first form, |
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.I bsdf2rad |
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takes a single XML file representing a Klems or tensor tree BSDF, plotting |
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as many scattering hemispheres as are present in the file. |
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In the second form, |
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.I bsdf2rad |
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takes up to four scattering interpolation representation (SIR) files, |
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each depicting the BSDF from one side of one incident hemisphere, |
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and plots them together. |
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An XML BSDF description may be imported from outside RADIANCE, or |
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produced by |
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.I genBSDF(1), |
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.I bsdf2klems(1), |
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or |
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.I bsdf2ttree(1). |
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(A program that produces SIR files is |
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.I pabopto2bsdf(1).)\0 |
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.PP |
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The output of |
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.I bsdf2rad |
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is a RADIANCE scene that contains a selection of 3-D plots showing |
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the given material's reflection and transmission scattering. |
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This description is normally sent to |
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.I oconv(1) |
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to create an octree for rendering using |
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.I rad(1), |
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.I rvu(1), |
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or |
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.I rpict(1). |
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.PP |
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To the right (+X) of the scene, the front incident hemisphere will be plotted. |
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To the left (-X) of the scene, the back incident hemisphere will be plotted. |
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Depending on the input, only one or the other hemisphere may be present. |
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In the case of an XML input, the hemispheres will be made of the specified |
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BSDF material, and the scene |
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will include a single (distant) light source shining straight |
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down from overhead (+Z direction). |
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.PP |
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Pink arrows will indicate the "through" (view) and "mirror" |
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(specular reflection) directions for each scatter plot. |
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The logarithmic scale of the BSDF plots themselves will be determined |
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automatically by the data and shown in a legend that lies between the |
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two hemisphere, or to the side if there is only one. |
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The incident direction may be read from the position of |
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each plot, where hemisphere grid lines are separated by |
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15 degree increments in the polar (theta, latitude) angle, and by |
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30 degree increments in the azimuthal (phi, longitude) angle. |
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The center (+Z) of each hemisphere corresponds to normal incidence, |
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and the right (+X) direction corresponds to a zero phi angle. |
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Positive phi is read counter-clockwise from above, |
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and a phi of 90 degrees (+Y) typically corresponds |
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to a material's "up" orientation. |
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.PP |
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If an optional plotting range is given with the |
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.I \-r |
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option, this will override automatic settings from the BSDF input. |
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This may be useful for comparing different BSDF sources. |
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.SH EXAMPLE |
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To view a BSDF XML representation: |
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.IP "" .2i |
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bsdf2rad cloth.xml | oconv - > cloth.oct |
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.br |
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rvu -vp 0 -50 50 -vd 0 50 -50 -vh 45 -vv 30 cloth.oct |
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.PP |
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To render an SIR description of a BRDF: |
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.IP "" .2i |
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bsdf2rad front_refl.sir back_refl.sir > refl.rad |
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.br |
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oconv -f refl.rad | rpict -vf good.vf > refl_good.hdr |
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.SH AUTHOR |
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Greg Ward |
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.SH "SEE ALSO" |
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bsdf2klems(1), bsdf2ttree(1), genBSDF(1), |
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bsdfview(1), oconv(1), pabopto2bsdf(1), pabopto2xyz(1), rad(1), rpict(1), rvu(1) |
