NAME

       mksource - compute distant sources for RADIANCE image-based lighting

SYNOPSIS

       mksource [ -d nsamps ][ -t thresh ][ -a maxang ] [ octree ]

DESCRIPTION

       Mksource  produces  a RADIANCE scene description of distant illum sources corresponding to
       bright, concentrated regions in the given ambient  environment.   Any  local  geometry  is
       ignored  in  the  input  octree,  which  should be derived from a captured light probe and
       modeled as a distant hemispherical or spherical glow source.  The output sources may  then
       be  combined with this environment to produce a more efficient scene for rendering, faster
       and less prone to sampling artifacts.

       The -d option may be used to specify the number of ray samples, which defaults to 262,000.
       Calculation  time  is roughly proportional to this setting, and the default is fine enough
       to resolve sources the size of the sun (half a degree) or larger.

       The -t option may be  used  to  manually  set  the  radiance  threshold  for  sources,  in
       watts/sr/meter^2.   The  default  uses  the  top 2 percentile of the environment, which is
       usally a good value.

       The -a option may be used to specify a maximum  source  diameter,  which  defaults  to  15
       degrees.  Mkillum silently enforces a maximum of 180 degrees for this option.

       If no input octree is specified, the standard input is read.

EXAMPLE

       To  add  sources  with  a  maximum  size  of  20  degrees  to the enviornment described in
       environ.oct:

         mksource -a 20 environ.oct > srcs.rad
         oconv -i environ.oct srcs.rad > env+srcs.oct

AUTHOR

       Greg Ward

SEE ALSO

       mkillum(1), rpict(1), rvu(1)