rsensor - Online in the Cloud

PROGRAM:

NAME

rsensor - compute sensor signal from a RADIANCE scene

SYNOPSIS

rsensor [ -n nprocs ][ -h ][ render options ] [ $EVAR ] [ @file ] { [ -rd nrays ][ -dn
nsrc ][ sensor_view ] sensor_file .. } octree
rsensor [ -h ] { [ -rd nrays ][ sensor_view ] sensor_file .. } .
rsensor [ options ] -defaults

DESCRIPTION

Rsensor traces rays outward from one or more specified illumination sensors into the
RADIANCE scene given by octree, sending the computed sensor value to the standard output.
(The octree may be given as the output of a command enclosed in quotes and preceded by a
`!'.) In the second form, a single period ('.') is given in place of an octree, and the
origin and directions of the specified number of rays will be printed on the standard
output. If these rays are later traced and added together, the results will sum to a
signal proportional to the given sensor distribution. In the third form, the default
values for the options (modified by those options present) are printed with a brief
explanation.

Options may be given on the command line and/or read from the environment and/or read from
a file. A command argument beginning with a dollar sign ('$') is immediately replaced by
the contents of the given environment variable. A command argument beginning with an at
sign ('@') is immediately replaced by the contents of the given file.

The sensor files themselves will be searched for in the path locations specified by the
RAYPATH environment variable, similar to other types of Radiance auxiliary files. If the
sensor file path begins with '/', '.' or '~', no search will take place. Before each
sensor file, a separate view may be specified. In this case, the view origin and
direction will correspond to the position and orientation of the sensor, and the view up
vector will determine the zero azimuthal direction of the sensor. The fore clipping
distance may be used as well, but other view options will be ignored. (See rpict(1) for
details on how to specify a view.) The actual data contained in the sensor file
corresponds to the SPOT tab-separated matrix specification, where the column header has
"degrees" in the leftmost column, followed by evenly-spaced azimuthal angles. Each row
begins with the polar angle, and is followed by the relative sensitivity values for each
direction. A low-resolution example of a sensor file is given below:

degrees 0 90 180 270
0 .02 .04 .02 .04
45 .01 .02 .01 .02
90 .001 .002 .001 .002

As well as different views, the number of samples may be changed between sensors, where
the -rd option controls the number of ray samples sent at random, and the -dn option
controls the number of rays sent to each light source per sensor.

The -h option toggles header output, which defaults to "on." The -n option may be used to
specify multiple calculation processes on systems with more than one CPU. For additional
options, consult the rtrace(1) man page. The final octree argument must be given, as the
octree cannot be read from the standard input.

EXAMPLES

To compute values for the same sensor with two different positions:

rsensor -ab 2 -vf posA.vf mysens.dat -vf posB.vf mysens.dat scene.oct

To generate a set of rays corresponding to a given sensor and compute the resulting signal
with rtrace:

rsensor -h -vf posC.vf mysens.dat . | rtrace -h scene.oct | total -m

ENVIRONMENT

RAYPATH the directories to check for auxiliary files.

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