diff --git a/doc/man/man1/bsdf2klems.1 b/doc/man/man1/bsdf2klems.1
index 8c17d8f19..6d9e975fe 100644
--- a/doc/man/man1/bsdf2klems.1
+++ b/doc/man/man1/bsdf2klems.1
@@ -1,4 +1,4 @@
-.\" RCSid $Id: bsdf2klems.1,v 1.7 2019/03/19 22:03:24 greg Exp $
+.\" RCSid $Id: bsdf2klems.1,v 1.8 2021/02/25 04:48:19 greg Exp $
 .TH BSDF2KLEMS 1 4/24/2013 RADIANCE
 .SH NAME
 bsdf2klems - generate XML Klems matrix description of a BSDF
@@ -172,5 +172,5 @@ RAYPATH		the directories to check for auxiliary files.
 Greg Ward
 .SH "SEE ALSO"
 bsdf2ttree(1), dctimestep(1), icalc(1), gendaymtx(1), genklemsamp(1),
-genskyvec(1), mkillum(1), genBSDF(1), pkgBSDF(1), rcontrib(1), rfluxmtx(1),
-rmtxop(1), wrapBSDF(1)
+genskyvec(1), mkillum(1), genBSDF(1), pabopto2bsdf(1), pabopto2xyz(1),
+pkgBSDF(1), rcontrib(1), rfluxmtx(1), rmtxop(1), wrapBSDF(1)
diff --git a/doc/man/man1/bsdf2rad.1 b/doc/man/man1/bsdf2rad.1
index 02ace989b..61b1ec221 100644
--- a/doc/man/man1/bsdf2rad.1
+++ b/doc/man/man1/bsdf2rad.1
@@ -1,4 +1,4 @@
-.\" RCSid "$Id: bsdf2rad.1,v 1.3 2020/01/22 21:50:56 greg Exp $"
+.\" RCSid "$Id: bsdf2rad.1,v 1.4 2021/02/25 04:48:19 greg Exp $"
 .TH BSDF2RAD 1 8/11/2017 RADIANCE
 .SH NAME
 bsdf2rad - create a RADIANCE visualization of a BSDF representation
@@ -97,4 +97,4 @@ oconv -f refl.rad | rpict -vf good.vf > refl_good.hdr
 Greg Ward
 .SH "SEE ALSO"
 bsdf2klems(1), bsdf2ttree(1), genBSDF(1),
-bsdfview(1), oconv(1), pabopto2bsdf(1), rad(1), rpict(1), rvu(1)
+bsdfview(1), oconv(1), pabopto2bsdf(1), pabopto2xyz(1), rad(1), rpict(1), rvu(1)
diff --git a/doc/man/man1/bsdf2ttree.1 b/doc/man/man1/bsdf2ttree.1
index f9f7fb044..b904d78a8 100644
--- a/doc/man/man1/bsdf2ttree.1
+++ b/doc/man/man1/bsdf2ttree.1
@@ -1,4 +1,4 @@
-.\" RCSid $Id: bsdf2ttree.1,v 1.9 2020/11/13 19:21:11 greg Exp $
+.\" RCSid $Id: bsdf2ttree.1,v 1.10 2021/02/25 04:48:19 greg Exp $
 .TH BSDF2TTREE 1 4/24/2013 RADIANCE
 .SH NAME
 bsdf2ttree - generate XML tensor tree description of a BSDF
@@ -178,5 +178,5 @@ RAYPATH		the directories to check for auxiliary files.
 .SH AUTHOR
 Greg Ward
 .SH "SEE ALSO"
-bsdf2klems(1), icalc(1), genBSDF(1), pkgBSDF(1), rcontrib(1),
-rfluxmtx(1), wrapBSDF(1)
+bsdf2klems(1), icalc(1), genBSDF(1), pabopto2bsdf(1), pabopto2xyz(1),
+pkgBSDF(1), rcontrib(1), rfluxmtx(1), wrapBSDF(1)
diff --git a/doc/man/man1/bsdfview.1 b/doc/man/man1/bsdfview.1
index 308c672a7..bb4be6a8c 100644
--- a/doc/man/man1/bsdfview.1
+++ b/doc/man/man1/bsdfview.1
@@ -1,4 +1,4 @@
-.\" RCSid "$Id: bsdfview.1,v 1.6 2018/07/20 00:50:40 greg Exp $"
+.\" RCSid "$Id: bsdfview.1,v 1.7 2021/02/25 04:48:19 greg Exp $"
 .TH BSDFVIEW 1 8/11/2017 RADIANCE
 .SH NAME
 bsdfview - view a BSDF representation
@@ -121,4 +121,4 @@ This may be useful for comparing different BSDF sources.
 Greg Ward
 .SH "SEE ALSO"
 bsdf2klems(1), bsdf2rad(1), bsdf2ttree(1), genBSDF(1),
-objview(1), oconv(1), pabopto2bsdf(1), rad(1), rvu(1), trad(1)
+objview(1), oconv(1), pabopto2bsdf(1), pabopto2xyz(1), rad(1), rvu(1), trad(1)
diff --git a/doc/man/man1/pabopto2bsdf.1 b/doc/man/man1/pabopto2bsdf.1
new file mode 100644
index 000000000..b102c3d30
--- /dev/null
+++ b/doc/man/man1/pabopto2bsdf.1
@@ -0,0 +1,214 @@
+.\" RCSid "$Id: pabopto2bsdf.1,v 1.1 2021/02/25 04:48:19 greg Exp $"
+.TH PABOPTO2BSDF 1 2/24/2021 RADIANCE
+.SH NAME
+pabopto2bsdf - convert pab-opto BSDF measurements to scattering interpolant representation
+.SH SYNOPSIS
+.B pabopto2bsdf
+[
+.B \-t
+][
+.B "\-n nproc"
+][
+.B "\-s symmetry"
+]
+.B "meas1 meas2 .."
+.SH DESCRIPTION
+.I Pabopto2bsdf
+takes two or more pab-opto
+.I Mountain
+files, each corresponding
+to a different incident beam angle, and produces a
+Scattering Interpolant Representation (SIR)
+on the standard output for further processing.
+The binary SIR contains a Radial Basis Function fitting
+each incident BSDF data file
+and a "transport plan" between neighboring RBF
+directions in a spherical Delaunay mesh.
+.PP
+The SIR provides a complete 4-dimensional
+BSDF description that may be resampled for other
+formats such as Klems and tensor tree.
+However, a separate run of
+.I pabopto2bsdf
+is needed to produce an SIR for each
+incident and scattered hemisphere pair.
+At most, there will be 4 such hemisphere pairs for
+front reflection, back reflection, front transmission,
+and back transmission.
+Theoretically, only one transmission direction is required,
+but it is often safest to measure both if both directions
+will be used in a simulation.
+.PP
+See
+.I bsdf2klems(1)
+and
+.I bsdf2ttree(1)
+for details.
+The
+.I bsdf2rad(1)
+and
+.I bsdfview(1)
+tools are also useful for visualizaing SIR and XML files.
+.PP
+The
+.I pabopto2bsdf
+.I \-t
+option reverses the assumed sample orientation front-to-back,
+and is discussed below under the "#intheta" header entry.
+Multi-processing may be used to accelerate the program
+on systems that support it via the
+.I \-n
+option.
+.PP
+BSDF symmetry may be specified with the
+.I \-s
+option, which is one of "isotropic", "quadrilateral",
+"bilateral", "up", or "anisotropic".
+Any of these may be abbreviated with as little as a single
+letter, and case is ignored.
+.PP
+Normally,
+.I pabopto2bsdf
+attempts to deduce BSDF symmetry from the incident phi angles
+provided.
+If every input data file uses the same incident phi angle, the
+BSDF is assumed to be "isotropic", meaning rotationally symmetric.
+If input phi angles only cover one quarter of the incident hemisphere,
+then the sample is assumed to have quadrilateral symmetry.
+Similarly, half-hemisphere coverage implies "bilateral" symmetry,
+although it is also compatible with "up" symmetry, which must be specified
+on the command line.
+The difference is crucial.
+Similar to quadrilateral symmetry, bilateral symmetry is "mirrored,"
+meaning that the sample material looks identical when viewed in a mirror.
+However, "up" symmetry means that the sample looks the same when
+rotated by 180-degree (upside-down), but does not look the same in a mirror.
+Although bilateral symmetry is a superset of "up" symmetry,
+we assume the former when provided only half of the input hemisphere.
+The "up" symmetry was a late addition, and involves rotating and copying the
+input data, treating the result as anisotropic.
+It is therefore less efficient, and should only be used when necessary.
+Finally, if the incident hemisphere is fully covered, the BSDF is also anisotropic.
+.PP
+If a
+.I \-s
+symmetry option is specified and it does not agree with the input
+data provided, an error message is issued and no output is produced.
+Note that only the "up" and "bilateral" symmetry options have
+identical input coverage, so this is the only time the
+.I \-s
+option must be specified if the default mirroring is inappropriate.
+.PP
+The
+.I Mountain
+software operates the pg2 goniophotometer to
+capture BSDF scattering data in separate files for each incident
+angle in a text file beginning with a header
+whose lines each start with a pound sign ('#').
+Some header settings require colons and others do not, as indicated below.
+The
+.i pabopto2bsdf
+program understands the following lines from each header and ignores
+the rest:
+.TP
+.BR #sample_name
+A double-quoted string containing the name associated with this sample.
+If input files contain different sample names, the one read
+will be the sample name passed to the SIR output.
+.TP
+.BR #format:
+The data format, typically one of "theta phi DSF" or "theta phi BSDF".
+These differ only in their inclusion of a cosine factor.
+The word "BRDF" or "BTDF" is accepted in place of "BSDF".
+Any other specification or a format missing generates an error.
+.TP
+.BR #intheta
+The incident theta (polar) angle in degrees, measured from the sample's
+surface normal.
+Theta values should be between 0 and 180, where values less than 90
+are considered incident to the "front" side of the sample, and
+theta values greater than 90 are incident to the "back" side in
+the standard coordinate system.
+Notions of sample "front" and "back" may be reversed using the
+.I -t
+option if desired.
+.TP
+.BR #inphi
+The incident phi (azimuthal) angle in degrees counter-clockwise as
+seen from the "front" side of the sample.
+.TP
+.BR #incident_angle
+The incident theta and phi angles are each given in this header
+line, offered as an alternative to separate "#intheta" and "#inphi"
+angles.
+The interpretation is the same as above.
+.TP
+.BR #upphi
+If present, this phi angle that corresponds to
+the sample "up" orientation.
+By default, it is assumed to be 0 degrees, meaning that "up"
+is phi=0.
+To get the standard RADIANCE coordinates for BSDFs, "#upphi" should
+be set to 90.
+.TP
+.BR #colorimetry:
+Two colorimetry values are currently understood, "CIE-Y" and "CIE-XYZ".
+The default colorimetry of "CIE-Y", which may be left unspecified,
+takes each DSF or BSDF value as photometric.
+If "CIE-XYZ" is specified, then the DSF or BSDF values must be triplets
+corresponding to CIE XYZ values.
+Such files are typically produced by the
+.I pabopto2xyz(1)
+tool rather than
+.I Mountain,
+directly.
+.PP
+The BSDF scattering data follows the header in unspecified order,
+where each line in the file
+contains the scattered theta and phi angles measured in the same
+coordinate system as incident theta and phi, followed by the DSF
+or BSDF value, which may either be a single photometric quantity
+for "CIE-Y" colorimetry or a triplet if the colorimetry is "CIE-XYZ".
+A minimal incident BSDF data file might contain:
+.sp
+.nf
+#incident_angle 82.5 180
+#format: theta phi DSF
+84.968 125.790 0.009744
+84.889 125.610 0.007737
+84.805 125.427 0.008569
+ ...
+.fi
+.sp
+The above header is equivalent to the more complete version below:
+.sp
+.nf
+#format: theta phi DSF
+#incident_angle 82.5 180
+#intheta 82.5
+#inphi 180
+#upphi 0
+#colorimetry: CIE-Y
+84.968 125.790 0.009744
+84.889 125.610 0.007737
+84.805 125.427 0.008569
+ ...
+.fi
+.sp
+The ordering of the header and data lines is unimportant,
+but all header lines must precede all data lines in each input file.
+.SH EXAMPLE
+To generate an SIR file from a collection of transmission measurements
+of a material with 180-degree symmetry using 4 processes:
+.IP "" .2i
+pabopto2bsdf -n 4 -s up f*_Tvis.txt > front_trans.sir
+.PP
+To combine this with front reflection measurements into a Klems BSDF file:
+.IP "" .2i
+pabopto2bsdf -n 4 -s up f*_Rvis.txt > front_refl.sir
+.br
+bsdf2klems front_trans.sir front_refl.sir > Klems_bsdf.xml
+.SH AUTHOR
+Greg Ward
+.SH "SEE ALSO"
+bsdf2klems(1), bsdf2rad(1), bsdf2ttree(1), bsdfview(1), pabopto2xyz(1)
\ No newline at end of file