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NAME

xform - transform a RADIANCE scene description

SYNOPSIS

xform [ -c ][ -I ][ -n name ][ -m newmod ][ xf0 ][ -a n1 xf1 .. ][ -i 1 xff ] file ..

DESCRIPTION

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.

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.

OPTIONS

-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.

-mx
Mirror the scene about the yz plane.

-my
Mirror the scene about the xz plane.

-mz
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 described below.

Arrays
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.

EXAMPLE

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 command expansion):

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

RAYPATH
path to search for scene files

AUTHOR

Greg Ward

BUGS

Only regular (distortion-free) transformations are allowed.

SEE ALSO

genbox(1), gensurf(1), oconv(1), replmarks(1), rpict(1), rview(1)


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XFORM(1) RADIANCE (6/18/96) XFORM(1)
Page 1 (printed 7/17/96)

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