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.\" RCSid "$Id: compamb.1,v 1.2 2003/12/09 15:59:06 greg Exp $" | 
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.TH COMPAMB 1 1/23/98 RADIANCE | 
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.SH NAME | 
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compamb - compute good ambient value for a rad input file | 
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.SH SYNOPSIS | 
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.B compamb | 
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[ | 
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.B \-c | 
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][ | 
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.B \-e | 
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] | 
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.B rad_input_file | 
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.SH DESCRIPTION | 
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.I Compamb | 
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computes a good ambient value for the specified | 
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.I rad(1) | 
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variable file and appends it to the file as a "render= \-av" option. | 
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If the | 
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.I \-c | 
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option is specified, then | 
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.I compamb | 
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includes color information in the computed ambient value, rather than | 
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estimating a grey value to avoid rendering color shifts. | 
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If the | 
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.I \-e | 
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option is specified, then | 
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.I compamb | 
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also computes a good exposure value for this scene, and appends it to | 
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the | 
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.I rad | 
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file as well. | 
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.PP | 
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.I Compamb | 
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is a shell script that makes calls to other RADIANCE programs and utilities | 
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to do the actual work. | 
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A substantial amount of time may be required to complete this script, since | 
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.I compamb | 
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calls | 
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.I rpict(1) | 
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to render low resolution frames for each view in the | 
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.I rad | 
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file, setting "QUALITY=High" to compute interreflections. | 
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The resulting ambient file is thrown away, since it would disagree | 
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with the new \-av setting used for the final renderings. | 
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This method is preferable to setting the | 
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.I \-aw | 
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option of | 
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.I rpict, | 
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which frequently results in splotchy artifacts. | 
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.SH AUTHOR | 
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Greg Ward Larson | 
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.SH "SEE ALSO" | 
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lookamb(1), rad(1), rpict(1) |