Provided by: radiance_4R1+20120125-1.1_amd64 bug


       compamb - compute good ambient value for a rad input file


       compamb [ -c ][ -e ] rad_input_file


       Compamb  computes  a good ambient value for the specified rad(1) variable file and appends
       it to the file as a "render= -av" option.  If the -c option  is  specified,  then  compamb
       includes  color  information  in the computed ambient value, rather than estimating a grey
       value to avoid rendering color shifts.  If the -e option is specified, then  compamb  also
       computes a good exposure value for this scene, and appends it to the rad file as well.

       Compamb  is a shell script that makes calls to other RADIANCE programs and utilities to do
       the actual work.  A substantial amount of time may be required to  complete  this  script,
       since  compamb  calls  rpict(1)  to  render low resolution frames for each view in the rad
       file, setting "QUALITY=High" to compute interreflections.  The resulting ambient  file  is
       thrown  away,  since  it  would  disagree  with  the  new  -av  setting used for the final
       renderings.  This method  is  preferable  to  setting  the  -aw  option  of  rpict,  which
       frequently results in splotchy artifacts.


       Greg Ward Larson


       lookamb(1), rad(1), rpict(1)