--- ray/doc/man/man1/rtcontrib.1	2005/05/26 21:03:22	1.4
+++ ray/doc/man/man1/rtcontrib.1	2005/06/01 16:11:01	1.6
@@ -1,7 +1,7 @@
-.\" RCSid "$Id: rtcontrib.1,v 1.4 2005/05/26 21:03:22 greg Exp $"
+.\" RCSid "$Id: rtcontrib.1,v 1.6 2005/06/01 16:11:01 greg Exp $"
 .TH RTCONTRIB 1 5/25/05 RADIANCE
 .SH NAME
-rtcontrib - compute contributions in a RADIANCE scene
+rtcontrib - compute contribution coefficients in a RADIANCE scene
 .SH SYNOPSIS
 .B rtcontrib
 [
@@ -51,8 +51,9 @@ systems, such as luminaires, light pipes, and shading 
 .I Rtcontrib
 calls
 .I rtrace(1)
-to calculate the contributions for each input ray,
-and the output tallies are sent to one or more files according to the
+with the -oTW option to calculate the daughter ray
+contributions for each input ray, and the output tallies
+are sent to one or more files according to the given
 .I \-o
 specification.
 If an output specification contains a "%s" format, this will be
@@ -98,6 +99,14 @@ The rules and predefined functions available for these
 described in the
 .I rcalc(1)
 man page.
+Unlike
+.I rcalc,
+.I rtcontrib
+will search the RADIANCE library directories for each file given in a
+.I \-f
+option.
+(No search takes place if a file name begins with a '.', '/' or '~'
+character.)\0
 .PP
 If no
 .I \-o
@@ -180,6 +189,8 @@ To compute an array of illuminance contributions accor
 .IP "" .2i
 rtcontrib -b tbin -o sky.dat -m skyglow -b 0 -o ground.dat -m groundglow
 @render.opt -f tregenza.cal scene.oct < test.dat
+.SH ENVIRONMENT
+RAYPATH		path to search for -f files
 .SH AUTHOR
 Greg Ward
 .SH "SEE ALSO"