1 .\" RCSid "$Id: compamb.1,v 1.3 2007/09/04 17:36:40 greg Exp $"

     2 .TH COMPAMB 1 1/23/98 RADIANCE

     3 .SH NAME

     4 compamb - compute good ambient value for a rad input file

     5 .SH SYNOPSIS

     6 .B compamb

     7 [

     8 .B \-c

     9 ][

    10 .B \-e

    11 ]

    12 .B rad_input_file

    13 .SH DESCRIPTION

    14 .I Compamb

    15 computes a good ambient value for the specified

    16 .I rad(1)

    17 variable file and appends it to the file as a "render= \-av" option.

    18 If the

    19 .I \-c

    20 option is specified, then

    21 .I compamb

    22 includes color information in the computed ambient value, rather than

    23 estimating a grey value to avoid rendering color shifts.

    24 If the

    25 .I \-e

    26 option is specified, then

    27 .I compamb

    28 also computes a good exposure value for this scene, and appends it to

    29 the

    30 .I rad

    31 file as well.

    32 .PP

    33 .I Compamb

    34 is a shell script that makes calls to other RADIANCE programs and utilities

    35 to do the actual work.

    36 A substantial amount of time may be required to complete this script, since

    37 .I compamb

    38 calls

    39 .I rpict(1)

    40 to render low resolution frames for each view in the

    41 .I rad

    42 file, setting "QUALITY=High" to compute interreflections.

    43 The resulting ambient file is thrown away, since it would disagree

    44 with the new \-av setting used for the final renderings.

    45 This method is preferable to setting the

    46 .I \-aw

    47 option of

    48 .I rpict,

    49 which frequently results in splotchy artifacts.

    50 .SH AUTHOR

    51 Greg Ward Larson

    52 .SH "SEE ALSO"

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