Arnold's command line renderer is called kick. This reads an .ass file, renders the scene using Arnold and outputs an image file. Kick can also be used to query Arnold nodes for their parameters and default values. It can also be used for scene debugging.
Kick is included in the plug-in downloads. After installation you will find it in the bin subdirectory of the Arnold distribution.
To run kick, first open a shell (terminal). Change directory to the bin subdirectory of the Arnold distribution, and then type "kick". Here's an example on Windows OS.
Probably the most useful command is "-h" or "--help". This will display a list of all the available options in kick.
Use the "-i" option to read an .ass file and render it.
Note that the "-i" option is not strictly necessary, kick automatically recognizes arguments ending in .ass, so this works too:
By default, a window will pop up displaying the image as it's being rendered. You can turn off the display window with the '-dw' option.
If the geometry is colored pink it could be because the path to the shaders may be required. This can be added using the "-l" flag.
An output gamma can be added to the output by using the '-g' flag.
Log information is sent to stdout. You can increase or decrease the log verbosity with the "-v <n>" option (default verbosity is 1). The most verbose option is "-v 6".
Switch off the log output with "-v 0"
To save the rendered image in an output file use the "-o" flag.
Change the render display size with the "-r <width> <height>" option.
Print the Arnold version number.
Print diagnostic information about the license servers and list installed licenses available and in use.
To override the antialiasing samples:
To override the diffuse GI samples (aka hemi samples):
To disable the progressive refinement mode:
For debugging purposes you can globally disable several features like textures, lights and shaders, motion blur, subdivs, displacement or SSS:
You can install custom Arnold nodes by loading them from a dynamic library (.dll or .so) with:
You can also get a list of all the installed nodes (both built-in and dynamically-loaded) with:
You can inspect nodes with "-info".
Or get more information about a given parameter.
Override any parameter of any node using the "-set" command.
Get kick to abort the render if no valid license is found, rather than rendering with a watermark.
Override several parameters:
To render in interactive mode use the "-interactive q" option. This will allow you to (very crudely) navigate the scene and switch to various debug shading modes such as flat/smooth normals, UVs, wireframe, etc:
Click in the render window and press lowercase "i" to ignore any existing shaders. Then use the number keys (0,1,2,3,4,5,6,7,8,9) to switch between the various debug shading modes. You can restore the scene shaders by pressing uppercase "i").
Navigate (pan/zoom) with the chosen interaction mode - q for Quake controls (WASD) and m for Maya controls (Alt + Mouse).