--- ray/doc/man/man1/rtcontrib.1	2005/05/27 19:15:28	1.5
+++ ray/doc/man/man1/rtcontrib.1	2005/06/02 04:47:26	1.7
@@ -1,4 +1,4 @@
-.\" RCSid "$Id: rtcontrib.1,v 1.5 2005/05/27 19:15:28 greg Exp $"
+.\" RCSid "$Id: rtcontrib.1,v 1.7 2005/06/02 04:47:26 greg Exp $"
 .TH RTCONTRIB 1 5/25/05 RADIANCE
 .SH NAME
 rtcontrib - compute contribution coefficients in a RADIANCE scene
@@ -11,7 +11,7 @@ rtcontrib - compute contribution coefficients in a RAD
 ][
 .B "\-f source"
 ][
-.B "\-o fspec"
+.B "\-o ospec"
 ][
 .B "\-b binv"
 ]
@@ -53,9 +53,13 @@ calls
 .I rtrace(1)
 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
+are sent to one or more destinations according to the given
 .I \-o
 specification.
+If a destination begins with an exclamation mark ('!'), then
+a pipe is opened to a command and data is sent to its standard input.
+Otherwise, the destination is treated as a file.
+(An existing file of the same name is clobbered.)\0
 If an output specification contains a "%s" format, this will be
 replaced by the modifier name.
 The
@@ -99,12 +103,20 @@ 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
 specification is given, results are written on the standard output in order
 of modifier (as given on the command line) then bin number.
-Concatenated data is also sent to a lone output file (i.e., an initial
+Concatenated data is also sent to a single destination (i.e., an initial
 .I \-o
 specification without formatting strings).
 If a "%s" format appears but no "%d" in the
@@ -181,6 +193,8 @@ 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"