--- ray/doc/man/man1/gensurf.1	2003/03/11 19:20:21	1.1
+++ ray/doc/man/man1/gensurf.1	2021/04/15 23:51:04	1.8
@@ -1,7 +1,7 @@
-.\" RCSid "$Id"
+.\" RCSid "$Id: gensurf.1,v 1.8 2021/04/15 23:51:04 greg Exp $"
 .TH GENSURF 1 11/15/93 RADIANCE
 .SH NAME
-gensurf - generate a RADIANCE description of a curved surface
+gensurf - generate a RADIANCE or Wavefront description of a curved surface
 .SH SYNOPSIS
 .B "gensurf mat name 'x(s,t)' 'y(s,t)' 'z(s,t)' m n"
 [
@@ -10,6 +10,8 @@ gensurf - generate a RADIANCE description of a curved 
 .B "\-f file"
 ][
 .B \-s
+][
+.B \-o
 ]
 .br
 .B "gensurf mat name 'x(s,t)' 'y(s,t)' dfile m n"
@@ -19,16 +21,20 @@ gensurf - generate a RADIANCE description of a curved 
 .B "\-f file"
 ][
 .B \-s
+][
+.B \-o
 ]
 .br
 .B "gensurf mat name dfile dfile dfile m n"
 [
 .B \-s
+][
+.B \-o
 ]
 .SH DESCRIPTION
 .I Gensurf
-produces a RADIANCE scene description of a
-functional surface defined by the parametric equations
+produces either a RADIANCE scene description or a Wavefront .OBJ
+file of a functional surface defined by the parametric equations
 .I x(s,t),
 .I y(s,t),
 and
@@ -54,9 +60,21 @@ in any number of
 and
 .I \-f
 options.
+The variable and function definitions in each
+.I \-f source
+file are read and compiled from the RADIANCE library where it is found.
 The
 .I \-s
 option adds smoothing (surface normal interpolation) to the surface.
+The
+.I \-o
+option produces a Wavefront .OBJ file rather than a RADIANCE
+scene description.
+This is most useful as input to the
+.I obj2mesh(1)
+program for producing a compiled mesh.
+A single "usemtl" statement will appear at the beginning
+of the .OBJ output, echoing the modifier given on the command line.
 .PP
 Rough holes may be cut in the mesh by defining a valid(s,t) function.
 Where this function is positive, polygon vertices will be produced.
@@ -93,11 +111,14 @@ gensurf crystal ball 'sin(PI*s)*cos(2*PI*t)' 'cos(PI*s
 To generate a 10x20 smoothed height field from 12 recorded vertex
 z values:
 .IP "" .2i
-gensurf dirt ground '10*s' '20*t' height.dat 2 3 -s
+gensurf dirt ground '10*s' '20*t' height.dat 2 3 \-s
+.SH ENVIRONMENT
+RAYPATH		the directories to check for auxiliary files.
 .SH AUTHOR
 Greg Ward
 .SH BUGS
 The smoothing operation requires that functions be defined
 beyond the [0,1] boundaries of s and t.
 .SH "SEE ALSO"
-calc(1), genbox(1), genrev(1), genworm(1), rpict(1), rview(1), xform(1)
+genbox(1), genrev(1), genworm(1), icalc(1),
+obj2mesh(1), obj2rad(1), robjutil(1), rpict(1), rvu(1), xform(1)