rad - Online in the Cloud

PROGRAM:

NAME

rad - render a RADIANCE scene

SYNOPSIS

rad [ -s ][ -n | -N npr ][ -t ][ -e ][ -V ][ -w ][ -v view ][ -o device ] rfile [
VAR=value .. ]

DESCRIPTION

Rad is an executive program that reads the given rfile and makes appropriate calls to
oconv(1), mkillum(1), rpict(1), pfilt(1), and/or rvu(1) to render a specific scene.
Variables in rfile give input files and qualitative information about the rendering(s)
desired that together enable rad to intelligently set parameter values and control the
simulation.

Normally, commands are echoed to the standard output as they are executed. The -s option
tells rad to do its work silently. The -n option tells rad not to take any action (ie.
not to actually execute any commands). The -N option instructs rad to run as many as npr
rendering processes in parallel. The -t option tells rad to bring rendering files up to
date relative to the input (scene description) files, without performing any actual
calculations. If no octree exists, it is still necessary to run oconv(1) to create one,
since the -t option will not create invalid (i.e. empty) files, and a valid octree is
necessary for the correct operation of rad. The -e option tells rad to explicate all
variables used for the simulation, including default values not specified in the input
file, and print them on the standard output.

Normally, rad will produce one picture for each view given in rfile. The -v option may be
used to specify a single desired view. The view argument may either be a complete view
specification (enclosed in quotes and beginning with an optional identifier) or a number
or single-word identifier to match a view defined in rfile. If the argument is one of the
standard view identifiers, it may or may not be further elaborated in rfile. (See "view"
variable description, below.) If the argument does not match any views in rfile and is
not one of the standard views, no rendering will take place. This may be convenient when
the only action desired of rad is the rebuilding of the octree. In particular, the
argument "0" will never match a view.

If the -V option is given, each view will be printed on the standard output before being
applied, in a form suitable for use in a view file or rpict rendering sequence. This is
helpful as feedback or for accessing the rad view assignments without necessarily starting
a rendering.

By default, rad will run rpict and pfilt to produce a picture for each view. The -o
option specifies an output device for rvu (usually "x11") and runs this interactive
program instead, using the first view in rfile or the view given with the -v option as the
starting point.

Additional variable settings may be added or overridden on the command line following
rfile. Upper case variables specified more than once will result in a warning message
(unless the -w option is present), and the last value given will be the one used.

The -w option turns off warnings about multiply and misassigned variables.

Rendering variable assignments appear one per line in rfile. The name of the variable is
followed by an equals sign ('=') and its value(s). The end of line may be escaped with a
backslash ('\'), though it is not usually necessary since additional variable values may
be given in multiple assignments. Variables that should have only one value are given in
upper case. Variables that may have multiple values are given in lower case. Variables
may be abbreviated by their first three letters. Comments in rfile start with a pound
sign ('#') and proceed to the end of line.

The rendering variables, their interpretations and default values are given below.

OCTREE The name of the octree file. The default name is the same as rfile but with any
suffix replaced by ".oct". (The octree must be a file -- rad cannot work with
commands that produce octrees.)

ZONE This variable specifies the volume of interest for this simulation. The first
word is either "Interior" or "Exterior", depending on whether the zone is to be
observed from the inside or the outside, respectively. (A single letter may be
given, and case does not matter.) The following six numbers are the minimum and
maximum X coordinates, minimum and maximum Y, and minimum and maximum Z for the
zone perimeter. It is important to give the zone as it is used to determine
many of the rendering parameters. The default exterior zone is the bounding
cube for the scene as computed by oconv.

EXPOSURE This variable tells rad how to adjust the exposure for display. It is important
to set this variable properly as it is used to determine the ambient value. An
appropriate setting may be discovered by running rvu and noting the exposure
given by the "exposure =" command. As in rvu and pfilt, the exposure setting
may be given either as a multiplier or as a number of f-stop adjustments (eg. +2
or -1.5). There is no default value for this variable. If it is not given, an
average level will be computed by pfilt and the ambient value will be set to 10
for exterior zones and 0.01 for interior zones.

EYESEP The interocular spacing for stereo viewing. I.e., the world distance between
the pupils of the left and right eyes. The default value is the sum of the
three "ZONE" dimensions divided by 100.

scene This variable is used to specify one or more scene input files. These files
will be given together with the materials file(s) and any options specified by
the "oconv" variable to oconv to produce the octree given by the "OCTREE"
variable. In-line commands may be specified in quotes instead of a file,
beginning with an exclamation mark ('!'). If the "scene" variable is not
present, then the octree must already exist in order for rad to work. Even if
this variable is given, oconv will not be run unless the octree is out of date
with respect to the input files. Note that the order of files in this variable
is important for oconv to work properly, and files given in later variable
assignments will appear after previous ones on the oconv command line.

materials This variable is used to specify files that, although they must appear on the
oconv command line, do not affect the actual octree itself. Keeping the
materials in separate files allows them to be modified without requiring the
octree to be rebuilt (a sometimes costly procedure). These files should not
contain any geometry, and the -f option must not be given in the "oconv"
variable for this to work.

illum This variable is used to specify files with surfaces to be converted into illum
sources by mkillum(1). When this variable is given, additional octree files
will be created to contain the scene before and after illum source conversion.
These files will be named according to the (default) value of the OCTREEE
variable, with either a '0' or a '1' appearing just before the file type suffix
(usually ".oct").

objects This variable is used for files that, although they do not appear on the oconv
command line, contain geometric information that is referenced indirectly by the
scene files. If any of these files is changed, the octree will be rebuilt.
(The raddepend(1) command may be used to find these dependencies
automatically.)

view This variable is used to specify a desired view for this zone. Any number of
"view" lines may be given, and each will result in a rendered picture (unless
the -v or -o option is specified). The value for this variable is an optional
identifier followed by any number of view options (see rpict(1) for a complete
listing). The identifier is used in file naming and associating a desired view
with the -v command line option. Also, there are several standard view
identifiers defined by rad. These standard views are specified by strings of
the form "[Xx]?[Yy]?[Zz]?[vlcahs]?". (That is, an optional upper or lower case
X followed by an optional upper or lower case Y followed by an optional upper or
lower case Z followed by an optional lower case V, L, C, A or H.) The letters
indicate the desired view position, where upper case X means maximum X, lower
case means minimum and so on. The final letter is the view type, where 'v' is
perspective (the default), 'l' is parallel, 'c' is a cylindrical panorama, ´a'
is angular fisheye, 'h' is hemispherical fisheye, and 's' is a planisphere
(stereographic) fisheye. A perspective view from maximum X, minimum Y would be
"Xy" or "Xyv". A parallel view from maximum Z would be "Zl". If "ZONE" is an
interior zone, the standard views will be inside the perimeter. If it is an
exterior zone, the standard views will be outside. Note that the standard views
are best used as starting points, and additional arguments may be given after
the identifier to modify a standard view to suit a particular model. The
default view is "X" if no views are specified. A single specified view of "0"
means no views will be automatically generated.

UP The vertical axis for this scene. A negative axis may be specified with a minus
sign (eg. "-Y"). There is no default value for this variable, although the
standard views assume Z is up if no other axis is specified.

RESOLUTION
This variable specifies the desired final picture resolution. If only a single
number is given, this value will be used for both the horizontal and vertical
picture dimensions. If two numbers are given, the first is the horizontal
resolution and the second is the vertical resolution. If three numbers are
given, the third is taken as the pixel aspect ratio for the final picture (a
real value). If the pixel aspect ratio is zero, the exact dimensions given will
be those produced. Otherwise, they will be used as a frame in which the final
image must fit. The default value for this variable is 512.

QUALITY This variable sets the overall rendering quality desired. It can have one of
three values, "LOW", "MEDIUM" or "HIGH". These may be abbreviated by their
first letter, and may be in upper or lower case. Most of the rendering options
will be affected by this setting. The default value is "L".

PENUMBRAS This is a boolean variable indicating whether or not penumbras are desired. A
value of "TRUE" will result in penumbras (soft shadows), and a value of "FALSE"
will result in no penumbras (sharp shadows). True and false may be written in
upper or lower case, and may be abbreviated by a single letter. Renderings
generally proceed much faster without penumbras. The default value is "F".

INDIRECT This variable indicates how many diffuse reflections are important in the
general lighting of this zone. A direct lighting system (eg. fluorescent
troffers recessed in the ceiling) corresponds to an indirect level of 0. An
indirect lighting system (eg. hanging fluorescents directed at a reflective
ceiling) corresponds to an indirect level of 1. A diffuse light shelf
reflecting sunlight onto the ceiling would correspond to an indirect level of 2.
The setting of this variable partially determines how many interreflections will
be calculated. The default value is 0.

PICTURE This is the root name of the output picture file(s). This name will have
appended the view identifier (or a number if no id was used) and a ".hdr"
suffix. If a picture corresponding to a specific view exists and is not out of
date with respect to the given octree, it will not be re-rendered. The default
value for this variable is the root portion of rfile.

RAWFILE This is the root name of the finished, raw rpict output file. If specified, rad
will rename the original rpict output file once it is finished and filtered
rather than removing it, which is the default action. The given root name will
be expanded in the same way as the "PICTURE" variable, and if the "RAWFILE" and
"PICTURE" variables are identical, then no filtering will take place.

ZFILE This is the root name of the raw distance file produced by the -z option of
rpict. To this root name, an underscore plus the view name plus a ".zbf" suffix
will be added. If no "ZFILE" is specified, none will be produced.

AMBFILE This is the name of the file where "ambient" or diffuse interreflection values
will be stored by rpict or rvu. Although it is not required, an ambient file
should be given whenever an interreflection calculation is expected. This will
optimize successive runs and minimize artifacts. An interreflection calculation
will take place when the "QUALITY" variable is set to HIGH, or when the
"QUALITY" variable is set to MEDIUM and "INDIRECT" is positive. There is no
default value for this variable.

DETAIL This variable specifies the level of visual detail in this zone, and is used to
determine image sampling rate, among other things. If there are few surfaces
and simple shading, then this should be set to LOW. For a zone with some
furniture it might be set to MEDIUM. If the space is very cluttered or contains
a lot of geometric detail and textures, then it should be set to HIGH. The
default value is "M".

VARIABILITY
This variable tells rad how much light varies over the surfaces of this zone,
and is used to determine what level of sampling is necessary in the indirect
calculation. For an electric lighting system with uniform coverage, the value
should be set to LOW. For a space with spot lighting or a window with sky
illumination only, it might be set to MEDIUM. For a space with penetrating
sunlight casting bright patches in a few places, it should be set to HIGH. The
default value is "L".

OPTFILE This is the name of a file in which rad will place the appropriate rendering
options. This file can later be accessed by rpict or rvu in subsequent manual
runs using the at-sign ('@') file insert option. (Using an "OPTFILE" also
reduces the length of the rendering command, which improves appearance and may
even be necessary on some systems.) There is no default value for this
variable.

REPORT This variable may be used to specify a reporting interval for batch rendering.
Given in minutes, this value is multiplied by 60 and passed to rpict with the -t
option. If a filename is given after the interval, it will be used as the error
file for reports and error messages instead of the standard error. (See the -e
option of rpict(1). There is no default value for this variable.

oconv This variable may be used to specify special options to oconv. If the first
word of the first instance of this variable is not an option, it will be used in
place of the default command path, "oconv". See the oconv(1) manual page for a
list of valid options.

mkillum This variable may be used to specify additional options to mkillum. If the
first word of the first instance of this variable is not an option, it will be
used in place of the default command path, "mkillum". See the rtrace(1) manual
page for a list of valid options.

render This variable may be used to specify additional options to rpict or rvu. These
options will appear after the options set automatically by rad, and thus will
override the default values.

rpict This variable may be used to specify overriding options specific to rpict. If
the first word of the first instance of this variable is not an option, it will
be used in place of the default command path, "rpict". See the rpict(1) man
page for a list of valid options.

rvu This variable may be used to specify overriding options specific to rvu. If the
first word of the first instance of this variable is not an option, it will be
used in place of the default command path, "rvu". See the rvu(1) man page for a
list of valid options.

pfilt This variable may be used to specify additional options to pfilt. If the first
word of the first instance of this variable is not an option, it will be used in
place of the default command path, "pfilt". See the pfilt(1) manual page for
details.

EXAMPLES

A minimal input file for rad might look like this:

::::::::::
sample.rif
::::::::::
# The octree we want to use:
OCTREE= tutor.oct # w/o this line, name would be "sample.oct"
# Our scene input files:
scene= sky.rad outside.rad room.rad srcwindow.rad
# The interior zone cavity:
ZONE= I 0 3 0 2 0 1.75 # default would be scene bounding cube
# The z-axis is up:
UP= Z # no default - would use view spec.
# Our exposure needs one f-stop boost:
EXPOSURE= +1 # default is computed ex post facto

Note that we have not specified any views in the file above. The standard default view
"X" would be used if we were to run rad on this file. If we only want to see what default
values rad would use without actually executing anything, we can invoke it thus:

rad -n -e sample.rif

This will print the variables we have given as well as default values rad has assigned for
us. Also, we will see the list of commands that rad would have executed had the -n option
not been present. (Note if the octree, "tutor.oct", is not present, an error will result
as it is needed to determine some of the opiton settings.)

Different option combinations have specific uses, ie:

rad -v 0 sample.rif OPT=samp.opt # build octree, put options in "sample.opt"
rad -n -e -s sample.rif > full.rif # make a complete rad file
rad -n sample.rif > script.sh # make a script of commands
rad -V -v Zl -n -s sample.rif > plan.vf # make a plan view file
rad -t sample.rif # update files after minor change to input
rad -s sample.rif & # execute silently in the background
rad -N 2 sample.rif # render views using two parallel rpict calls
rad -N 4 -v 1 sample.rif # render first view with four rpiece calls

If we decide that the default values rad has chosen for our variables are not all
appropriate, we can add some more assignments to the file:

QUAL= MED # default was low
DET= low # default was medium - our space is almost empty
PEN= True # we want to see soft shadows from our window
VAR= hi # daylight can result in fairly harsh lighting
view= XYa -vv 120 # let's try a fisheye view
PICT= tutor # our picture name will be "tutor_XYa.hdr"

Note the use of abbreviations, and the modification of a standard view. Now we can invoke
rad to take a look at our scene interactively with rvu:

rad -o x11 sample.rif

Rad will run oconv first to create the octree (assuming it doesn't already exist), then
rvu with a long list of options. Let's say that from within rvu, we wrote out the view
files "view1.vp" and "view2.vp". We could add these to "sample.rif" like so:

view= vw1 -vf view1.vp # Our first view
view= vw2 -vf view2.vp # Our second view
RESOLUTION= 1024 # Let's go for a higher resolution result

To start rvu again using vw2 instead of the default, we use:

rad -o x11 -v vw2 sample.rif

Once we are happy with the variable settings in our file, we can run rad in the background
to produce one image for each view:

rad sample.rif REP=5 >& errfile &

This will report progress every five minutes to "errfile".

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