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xform (1)
NAME
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xform - transform a RADIANCE scene description |
SYNOPSIS
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xform [ -c ][ -I ][ -n name ][
-m newmod ][ -f argfile ][ xf0 ][ -a
n1 xf1 .. ][ -i 1 xff ] file
.. |
DESCRIPTION
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Xform transforms each scene description file
according to the options given. The -c option causes
commands in the file not to be expanded. The default is to
execute all in line commands. (See note below about file
names.) The -n option causes all identifiers to be
prefixed with name. The -m option causes all
surfaces to be given the modifier newmod. The
-I option causes all surfaces to be inverted,
reversing their surface normal orientations. These options
are followed by the transformation options, which are
described below. |
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The -f option causes the xform command line to
be constructed from the given file, by inserting each line
of the file at the current point in the command argument
list. Each line in the file will result in a logically
separate invocation of xform, and may may contain any
valid xform arguments, including nested -f
options. This is a convenient way to specify multiple copies
of an object that do not fit a regular array pattern,
without having to actually execute xform many times.
Separate scene files may be specified this way as well, but
remember that the constructed command line must fit the
format of initial options (-n, -m, -c, -I) followed
by the transform then the scene files. No initial options
may appear after the first transform option, and no
transform options will be understood after the first named
scene file. In the special case where the argument to the
-f option is a hyphen ('-'), xform will take
its arguments from the standard input. Note that
xform cannot simultaneously take its scene
information from the standard input if the option is used in
this way. Competely empty lines and lines beginning with a
pound sign ('#') will be silently ignored. Beginning
"!xform" or "xform" command names will
also be ignored. |
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If one or more scene files are given on the command line,
xform will search the RADIANCE library directories
for each file. (No search takes place if a file name begins
with a '.', '/' or '~' character.) Unless the -c
option is present, xform will also change to that
file's directory before loading it. Thus, any commands
executed within that file will happen in that file's
directory, which simplifies object hierarchy construction.
If no file is given, the standard input is
read. |
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The transformation consists of a sequence of operations
which are executed in the order they appear. |
OPTIONS
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Translate the scene along the vector x y z
. |
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Rotate the scene degrees about the x axis. A positive
rotation corresponds to counter-clockwise when looking down
the axis. |
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Rotate the scene degrees about the y
axis. |
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Rotate the scene degrees about the z
axis. |
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Scale the scene by factor. |
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Mirror the scene about the yz plane. |
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Mirror the scene about the xz plane. |
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Mirror the scene about the xy plane. |
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Iterate (repeat) the following transformation (up to the
next -i option) count times. This option is
primarily to support the -a option, which is
described below. |
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An array is a repeated transformation that results in a
repeated object. It is specified using the -a option,
which takes the number to repeat as its argument. The
objects will step by the transformation given between this
-a option and the next -a or -i option.
The first object will have zero applications of the
transform. A two-dimensional array is given by two different
transformations each preceded by an array
count. |
EXAMPLE
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To rotate ``book'' 30 degrees about the x axis then move 20
in y, prepending the name book1: |
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xform -n book1 -rx 30 -t 0 20 0 book > book1 |
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To expand all commands and see what information is actually
used by RADIANCE: |
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To create a two-dimensional array of 20 lights, after an
initial rotation and followed by a global translation (no
command expansion): |
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xform -c -rz 90 -a 5 -t 2 0 0 -a 4 -t 0 1.5 0 -i 1 -t 0 0 10
light |
ENVIRONMENT
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RAYPATH path to search for scene files |
AUTHOR
BUGS
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Only regular (distortion-free) transformations are
allowed. |
SEE ALSO
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