PLOT3ROT(1)

NAME

plot3rot - rotate, translate, or scale a UnixPlot file

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SYNOPSIS
DESCRIPTION
OPTIONS
EXAMPLES
SEE ALSO
AUTHOR
COPYRIGHT
BUG REPORTS

SYNOPSIS

plot3rot [-x _angle_] [-y _angle_] [-z _angle_] [-X _dist_] [-Y _dist_] [-Z _dist_] [-s _factor_] [-a _az_] [-e _el_] [-g] [-M] [-m _matrix_] [-S _space_] [-v] [_file_ ...] > unix_plot

plot3rot rotates, translates, and/or scales a UnixPlot file (see plot3(5)). Input is read from the named file arguments (a file of - means standard input), or from standard input if no files are given, and the transformed plot is written to standard output.

Any number of transformation options may be given. Each operation is applied left to right in the order it appears on the command line, and the operations are concatenated into a single transform. Because rotations are not commutative, the order in which they are specified matters. Invoking the command with no arguments prints a usage summary.

The lower case -x, -y, and -z options rotate about the X, Y, and Z axes respectively by the given number of degrees; a positive value is a right handed rotation. The upper case -X, -Y, and -Z options translate along those axes in whatever units the plot file uses. The -s option applies a scale factor, up (> 1) or down (< 1).

The -a and -e options are azimuth and elevation about the center point. They are shorthand for a positive Z axis and a negative X axis rotation respectively, and should be given in that order for the proper combined effect. They also cause the plot to be auto-centered based on the "space" command found in the input, with the new "space" command shrunk to fit the rotated plot as tightly as possible. (This differs from -M, which instead fits a sphere to the space; see below.)

The -M option auto-centers the plot on its "space" command in much the same way that the rt(1) ray tracer treats a model bounding box: a sphere is fit to the space, and the diameter and center of that sphere are used as the width and center of the plot in all three dimensions. This keeps the entire model in view from any angle and is invariant with respect to viewing direction, but the "space" is enlarged on every cascaded pass through plot3rot in which -M is used.

The -g option is a convenient shorthand to transform azimuths and elevations expressed in gift/MGED front-view notation (degrees off the -X view) into the UnixPlot screen coordinate system, where X increases to the right and Y increases up. It should usually appear last, because it modifies the rotation already established, and is exactly equivalent to giving -z -90 -x -90 in the same place. Do not combine -m with -a, -e, or -g.

OPTIONS

-x angle: Rotate angle degrees about the X axis.
-y angle: Rotate angle degrees about the Y axis.
-z angle: Rotate angle degrees about the Z axis.
-X dist: Translate dist units along the X axis.
-Y dist: Translate dist units along the Y axis.
-Z dist: Translate dist units along the Z axis.
-s factor: Scale by factor (> 1 enlarges, < 1 shrinks). A factor of zero is rejected.
-a az: Apply azimuth az, a positive Z axis rotation. Auto-centers the plot and re-bounds the "space" tightly to the rotated plot; should precede -e.
-e el: Apply elevation el, a negative X axis rotation. Auto-centers the plot and re-bounds the "space" tightly to the rotated plot.
-g: Convert gift/MGED front-view azimuth and elevation into UnixPlot display coordinates. Equivalent to -z -90 -x -90; usually given last.
-M: Auto-center the "space" command like the rt(1) model RPP, fitting a sphere so the model stays in view from any angle.
-m matrix: Apply the 4x4 transformation matrix given as a quoted string of 16 floating point numbers (see h/vmath.h). Do not combine with -a, -e, or -g.
-S space: Force the output "space" to a quoted string of six floats ("min_x min_y min_z max_x max_y max_z"). This is emitted immediately and overrides any space derived from the input or other options.
-v: Verbose mode. Print the initial transformation matrix, and for every "space" command encountered print the old and new bounding RPP.

EXAMPLES

Example 1. Rotate a plot about two axes

plot3rot -z 30 -x 20 < file.plot3 > file2.plot3

Performs a 30 degree positive rotation about the Z axis (counter clockwise as viewed from the top), then a 20 degree rotation about the already-rotated X axis. Reversing the order of the options would not produce the same result, since rotations do not commute.

Example 2. View a model as a ray tracer would, then frame buffer display it

rthide -a 35 -e 25 -o file.plot3 model.g component
plot3rot -a 35 -e 25 -g < file.plot3 | plot3-fb

rthide(1) renders a hidden-line plot at azimuth 35 and elevation 25. The trailing -g converts that gift-style azimuth/elevation into the conventional UnixPlot screen coordinate system before plot3-fb(1) displays it on a frame buffer.