Options

This appendix describes the command-line arguments accepted by rayshade. These options override defaults as well as any values or flags given in the input file, and are thus useful for generating test and other unusual, ``non-standard'' renderings.

The general form of a rayshade command line is:

rayshade [Options] [filename]

If given, the input file is read from filename. By default, the input file is read from the standard input. Recall that, by default, the image file is written to the standard output; you will need to redirect the standard output if you have not chosen to write the image to a file directly. The name of the input file may be given anywhere on the command line.

Command-line options fall into two broad categories: those that set numerical or other values and thus must be followed by further arguments, and those that simply turn features on and off. Rayshade's convention is to denote the value-setting arguments using capital letters, and feature-toggling arguments using lower-case letters.

: -A frame
Begin rendering (action) on the given frame.

The default starting frame is number zero.

: -a
Toggle writing of alpha channel.

This option is only available when the Utah Raster Toolkit is being used.

: -C R G B
Set the adaptive ray tree pruning color. If all channel contributions falls below the given cutoff values, no further rays are spawned.

Overrides the value specified via the cutoff keyword.

: -c
Continue an interrupted rendering.

When given, this option indicates that the image file being written to contains a partially-completed image. Rayshade will read the image to determine the scanline from which to continue the rendering. This option is only available with the Utah Raster Toolkit. The -O option must also be used.

: -D depth
Set maximum ray tree depth.

Overrides the value specified in the input file via the maxdepth keyword.

: -E separation
Set eye separation for rendering of stereo pairs.

Overrides the value specified via the eyesep keyword.

: -e
Write exponential RLE file.

This option is only available for use with the Utah Raster Toolkit. See the Utah Raster Toolkit's unexp manual page for details on exponential RLE files.

: -F freq
Set frequency of status report.

Overrides the value given using the report keyword.

: -f
Flip all computed polygon (and triangle) normals.

This option should be used when rendering polygons defined by vertices given in clockwise order, rather than counter-clockwise order as expected by rayshade.

: -G gamma
Use given gamma correction exponent writing writing color information to the image file.

The default value for gamma is 1.0.

: -g
Use a Gaussian pixel filter.

Overrides the filter selected through the use of the filter keyword.

: -h
Print a short use message.

: -j
Toggle the use of jittered sampling to perform antialiasing. If disabled, a fixed sampling pattern is used.

: -l
Render the left stereo pair image.

: -m
Write a sampling map to the alpha channel.

Rather than containing coverage information, the alpha channel values will be restricted to zero, indicating no supersampling, and full intensity, indicating supersampling. This option is only available if the Utah Raster Toolkit is being used.

: -N frames
Set the total number of frames to be rendered.

This option overrides any value specified through the use of the frames keyword. By default, a single frame is rendered.

: -n
Do not render shadows.

: -O outfile
Write the image to the named file.

This option overrides the name given with the outfile keyword, if any, in the input file.

: -o
Toggle the effect of object opacity on shadows.

This option is equivalent to specifying shadowtransp in the input file. By default, rayshade traces shadow rays through non-opaque objects.

: -P cpp-arguments
Specify the options that should be passed to the C preprocessor.

The C preprocessor, if available, is applied to all of the input passed to rayshade.

: -p
Perform preview-quality rendering.

This option is equivalent to -n -S 1 -D 0.

: -q
Do not print warning messages.

: -R xsize ysize
Produce an image xsize pixels wide by ysize pixels high.

This option overrides any screen size set by use of the screen keyword.

: -r
Render the right stereo pair image.

: -S samples
Use samples² jittered samples.

This option overrides any value set through the use of the samples keyword in the input file.

: -s
Disable caching of shadowing information.

It should never be necessary to use this option.

: -T r g b
Set the contrast threshold in the three color channels for use in adaptive supersampling.

This option overrides any value given through the use of the contrast keyword.

: -u
Toggle the use of the C preprocessor.

Rayshade usually feeds its input through a C preprocessor if one is available on your system. If this option is given, unadulterated input files will be used.

: -V filename
Write verbose output to the named file.

This option overrides any file named through the use of the report keyword.

: -v
Write verbose output.

When given, this option causes information about the options selected and the objects defined to be included in the report file.

: -W minx maxx miny maxy
Render the specified window.

The window must be properly contained within the screen. This option overrides any window specified using the window keyword in the input file.

: -X left right bottom top
Crop the rendering window using the given normalized values.

This option is provided to facilitate changing and/or examining a small portion of an image without having to re-render the entire image.