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xform - transform a RADIANCE scene description
xform [ -c ][ -I ][ -n name ][ -m newmod ][ xf0 ][ -a n1 xf1
.. ][ -i 1 xff ] file ..
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
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.
The transformation consists of a sequence of operations
which are executed in the order they appear.
-t x y z Translate the scene along the vector x y z .
- -rx degrees
Rotate the scene degrees about the x axis. A
positive rotation corresponds to counter-clockwise
when looking down the axis.
- -ry degrees
Rotate the scene degrees about the y axis.
- -rz degrees
Rotate the scene degrees about the z axis.
- -s factor Scale the scene by factor.
- Mirror the scene about the yz plane.
- Mirror the scene about the xz plane.
- Mirror the scene about the xy plane.
- -i count
- Iterate (repeat) the following transformation (up
to the next -i option) count times. This option
is primarily to support the -a option, which is
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 followed by
an array count.
To rotate ``book'' 30 degrees about the x axis then move 20
in y, prepending the name book1:
xform -n book1 -rx 30 -t 0 20 0 book > book1
To expand all commands and see what information is actually
used by RADIANCE:
xform scene | more
To create a two dimensional array of 20 lights, after an
initial rotation and followed by a global translation (no
xform -c -rz 90 -a 5 -t 2 0 0 -a 4 -t 0 1.5 0 -i 1 -t 0 0
- path to search for scene files
Only regular (distortion-free) transformations are allowed.
genbox(1), gensurf(1), oconv(1), replmarks(1), rpict(1),
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XFORM(1) RADIANCE (6/18/96) XFORM(1)
Page 1 (printed 7/17/96)
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