.\" 
.TH "LTVIEW" "1" "08/04/14" "RADIANCE" ""
.SH "NAME"
ltview \- view photometry of a light source
.SH "SYNOPSIS"
.B ltview
[
.B \-i
][
.B "\-b boxsize"
][
.B "\-o output device"
]
input
.SH "DESCRIPTION"
.I ltview
renders a Radiance luminiare or IES photometry interactively using
.I rad(1)
.  This program is merely a shell script that calls
.I rad(1)
to make an octree and view the scene interactively.
.PP 
.I ltview
accepts exactly one Radiance object or IES photometry
file as input.  No input is taken from STDIN.  The
.I \-i
option tells it that the file name given is 
an IES photometry file rather then a Radiance description of a 
luminiare.  In this case, Radiance's
.I ies2rad(1)
is called with its default settings to convert the IES file into a 
Radiance object.
.PP 
Unlike
.I objpict(1)
or
.I objview(1)
, no additional light sources are added to the scene, since it is
assumed that the object is a luminaire.
.PP 
.I ltview
relies on Radiance's
.I rad(1)
command to compile an octree using 
.I oconv(1)
and to call
.I rvu(1)
to display an interactive preview of the luminaire.
The default behaviour for
.I ltview
is to scale the luminaire or output from 
.I ies2rad(1)
so that the largest dimension of the fitting is unity, centered at the origin.
This scaled representation of the original fitting is then placed inside a 
square box 10 units in length.  The \-y face of the box is left open so that 
the camera can look inside, facing +y.
If it is desirable to keep the original luminaire in both its original size,
and its original location, the
.I "\-r roomsize"
option may be used to fix the room size to a certain
.I roomsize.
In this case, the size and location of the fitting is not adjusted, and
it is up to the user to decide on appropriate room dimensions.  Note that
when
.I \-r
and
.I \-i
are combined, then the dimensions of the luminaire and intesity of its 
output are determined by
.I ies2rad(1)'s
default settings.  If this is not acceptable, then it is best to run
.I ies2rad(1)
manually, and to feed
.I ltview
the hand\-crafted fitting, rather than the IES photometry.
.PP 
The default
.I rvu(1)
output device is
.I x11
on all platforms except for Windows, where it is set to
.I qt.
This may be overwritten with the
.I "\-o output"
option.

.SH "EXAMPLES"
To query available output devices
.IP "" .2i
rvu \-devices
.PP 
To visualise an IES file with the qt driver
.IP "" .2i
ltview \-o qt ABC123.ies
.PP 
To look at a typical fluorescent fitting that is modelled in millimeters
.IP "" .2i
ltview \-r 5000 XYZ_batten.rad
.SH "AUTHOR"
Axel Jacobs
.SH "SEE ALSO"
ltpict(1), ies2rad(1), oconv(1), rad(1), rvu(1)