Nuke Environment Variables

The following table lists the environment variables Nuke recognizes.

Environment Variable

Description

CUDA_CACHE_MAXSIZE

Allows you to increase the size of the CUDA cache to accommodate kernels compiled by AIR nodes on Ampere GPUs.

See AIR Nodes on Ampere GPUs for more information.

CUDA_CACHE_PATH

Allows you to change the location of the CUDA cache. The default paths are:

Windows

%APPDATA%\NVIDIA\NukeComputeCache

macOS

$HOME/Library/Application Support/NVIDIA/NukeComputeCache

Linux

~/.nv/NukeComputeCache

FN_CRASH_DUMP_PATH

Allows you to specify where Issue Reporter dumps are saved by default.

FN_DISABLE_LICENSE_DIALOG

or

FN_NUKE_DISABLE_TMPLIC_NOTIFY_DIALOG

By default, if you have installed a temporary license, Nuke displays a dialog at start-up alerting you to the number of days remaining. If you want to disable this behavior, you can set either of these environment variables to 1 to suppress the warning message about imminent license expiration.

Note:  You still get a warning if no license is found, for example if you only have a Nuke license but you try to run NukeX.

FN_LICENSE_DIALOG_DAYS_LEFT_BEFORE_PROMPT

By default, if you have installed a temporary license, Nuke displays a dialog at start-up alerting you to the number of days remaining. If you want to disable this behavior until a set number of days before expiry, you can set this environment variables to the required number of days.

Note:  You still get a warning if no license is found, for example if you only have a Nuke license but you try to run NukeX.

FN_NUKE_DISABLE_GPU_ACCELERATION

This variable disables Nuke's CUDA and OpenCL capabilities. When enabled, any GPUs installed locally are disabled and cannot be selected from Preferences > Performance > Hardware > default blink device dropdown. Any GPU accelerated nodes, such as Kronos and Denoise, default to processing on the CPU.

FN_SUBSCRIPTION_LICENSE_DIR

On Windows, user names containing non-ASCII characters can cause subscription licensing to fail. If a licensing error similar to the following displays:

Unable to create subscription license directory: C:\Users\Zoë Hernández\FoundryLicensing\

Try changing the license directory to an alternate location using this environment variable.

foundry_LICENSE

The location of the Nuke RLM license file, if the following recommended location is not used:

On Mac and Linux:

/usr/local/foundry/RLM

On Windows:

drive letter:\Program Files\The Foundry\RLM

Note:  If you still use FLEXlm licenses and you're interested in making a move to RLM licensing, please contact sales@foundry.com to obtain a replacement license.

FOUNDRY_LICENSE_DEBUG

This variable prints additional licensing information to the command line or Terminal.

FOUNDRY_LICENSE_FILE

The location of the Nuke FLEXlm license file, if the following recommended location is not used:

On Mac and Linux:

/usr/local/foundry/FLEXlm

On Windows:

drive letter:\Program Files\The Foundry\FLEXlm

Note:  If you still use FLEXlm licenses and you're interested in making a move to RLM licensing, please contact sales@foundry.com to obtain a replacement license.

FOUNDRY_LOG_FILE

This variable specifies the location of Nuke Studio’s logfile. If you don’t specify a logfile, all output is to screen.

FOUNDRY_LOG_LEVEL

This variable sets the level of logging Nuke Studio produces during operation. There are four levels of detail, on a sliding scale from minimal to verbose:

error

warning

message

verbose

Note:  Setting the logging level to verbose can produce large log files when FOUNDRY_LOG_FILE is specified.

FRAMESERVER_LOG_DIR

This variable is used to specify a different location for the Frame Server to write log files to, if you'd like to keep them separate from the default NUKE_TEMP_DIR.

See Using the Frame Server on Render Machines for more information.

HIERO_DISABLE_THUMBNAILS

Set this variable to stop Nuke Studio loading thumbnails.

HIERO_DISABLE_THUMBNAILS_CACHE

Set this variable to stop Nuke Studio caching thumbnails for improved access once loaded.

Note:  This variable does not clear the cache, you must remove cached files manually.

NUKE_AJA_CHANNEL

AJA cards take a 3G level signal (mostly for 12-bit 444 RGB) and combine it into a single 3G-B (B denotes B level, hence the 3G-B) stream through SDI1 by default. Set this environment variable to 2, 3, or 4 to output a single stream through SDI2, SDI3, or SDI4.

NUKE_ALLOW_GIZMO_SAVING

Nuke does not allow you to Overwrite and Save as gizmos by default, without copying the gizmo to a Group. Setting this environment variable to 1 enables this behavior, so artists don't need to copy a gizmo before editing it.

NUKE_CRASH_HANDLING

Breakpad crash reporting allows you to submit crash dumps to Foundry in the unlikely event of a crash. By default, crash reporting is enabled in GUI mode and disabled in terminal mode.

When NUKE_CRASH_HANDLING is set to 1, crash reporting is enabled in both GUI and terminal mode.

When NUKE_CRASH_HANDLING is set to 0, crash reporting is disabled in both GUI and terminal mode.

NUKE_DEBUG_IMAGECACHE

When enabled, Comp Viewer image cache data is printed to the command line or Terminal. Information on disk space used, the number of files cached, and the cache location is displayed.

NUKE_DEBUG_MEMORY

When working on large images, Nuke may need to free up memory during rendering. When this happens and NUKE_DEBUG_MEMORY is set to 1, Nuke prints the following information to the console:

Memory: over maximum usage, trying to reduce usage from 1 GB to 924 MB.

If this variable is not set, you cannot see the debug memory messages.

Note that here, KB, MB, GB, and TB mean units of 1000. For example, 1MB means 1,000,000 bytes.

NUKE_DISK_CACHE

The location where Nuke saves all recent images displayed in the Viewer. Ideally, this should be a local disk with the fastest access time available.

NUKE_DISK_CACHE_GB

The maximum size the disk cache can reach (in gigabytes).

NUKE_EXR_TEMP_DIR

On Linux, this is the location Nuke uses for temporary files while reading PIZ-compressed .exr files. This environment variable is only relevant on Linux.

If this variable is not set, the location is determined by NUKE_TEMP_DIR.

NUKE_EXR_TEMP_NAME

Changes the naming convention of .exr temporary files during rendering.

Setting the variable to 1 writes temporary .exr files as <filename>.exr.tmp, rather than <filehash>.tmp as in previous releases.

NUKE_FONT_PATH

The location that Nuke checks for available font files when the Text node properties panel is opened.

NUKE_IGNORE_ROTO_INCOMPATIBILITY

This variable disables the warning dialog displayed when you open scripts containing pre-Nuke 8 RotoPaint nodes.

NUKE_INTERACTIVE

The import nuke function checks-out a nuke_r render license by default. If you want to use Nuke interactively, and you have an interactive license, set this environment variable to 1.

See Nuke as a Python Module for more information.

NUKE_LEGACY_CHANNEL_SORTING

This variable disables the new channel sorting behavior, where the RGBA layer is sorted first. Enabling this variable causes Nuke to sort channels alphabetically.

NUKE_LOCALIZATION_NUMWATCHERS

Controls the number of threads used for querying the file system, such as checking if localized files are out of date, if they exist, and so on. The actual copying of files is done in a separate thread pool with only 1 thread, which is fixed.

NUKE_NO_CRASH_PROMPT

When crash handling is enabled in GUI mode, this allows you to control whether reports are automatically submitted or not:

When NUKE_NO_CRASH_PROMPT is set to 1, crash reports are submitted automatically without displaying a crash reporter dialog.

When NUKE_NO_CRASH_PROMPT is set to 0, Nuke always displays a crash reporter dialog before submitting a crash report.

NUKE_NO_VIEWER_GPU

Disables Nuke's Comp Viewer OpenGL hardware acceleration.

NUKE_OCIO_ROLES

Controls the state of the Prioritize OCIO Roles preference. This variable allows you to set the desired behavior at an environment level for all artists, rather than allowing individual artists to change the preference.

NUKE_OCIO_ROLES=0 Roles are hidden.

NUKE_OCIO_ROLES=1 Roles are prioritized, which is the same behavior as Nuke 12.2 releases.

NUKE_OCIO_ROLES=2 Roles are de-prioritized.

Note:  If the variable is set, the Prioritize OCIO Roles preference is disabled.

NUKE_PATH

The location where files related to Nuke customizations are stored. For more information, see Loading Gizmos, NDK Plug-ins, and Python and Tcl Scripts.

NUKE_TEMP_DIR

The location where Nuke saves any temporary files that do not have a particular place defined for them.

You can find the current location of Nuke's temporary directory from within Nuke by pressing X on your keyboard, when the focus is on the Node Graph, and then running the following TCL command:

getenv NUKE_TEMP_DIR

NUKE_WINDOWMANAGER_DEBUG

When enabled, data from Nuke's window manager is printed to the command line or Terminal.

OCIO

Set this variable to the location of your OCIO configuration file for color conversion.

Note:  If you plan to use the OCIO config file specified in the Preferences, ensure that the Preferences > Project Defaults > Color Management > Export > use OCIO nodes when exportingto a Comp checkbox is enabled.

OFX_PLUGIN_PATH

The location where Nuke looks for OFX plug-ins. For more information, see Loading OFX Plug-ins.

QT_AUTO_SCREEN_SCALE_FACTOR

Controls whether or not automatic interface scaling for high resolution screens is enabled. On Windows, this variable is enabled (1) by default. On Linux distributions, scaling is currently disabled (0) by default.

Note:  macOS handles scaling automatically, so this variable is not required.

QT_COMPRESS_TABLET_EVENTS

Due to recent updates to Qt, running Nuke on CentOS 7 Linux distributions with a tablet can cause lag when moving Roto shapes around the Viewer. Setting this environment variable compresses tablet events, eliminating the lag.

QT_SCALE_FACTOR

Sets the automatic interface scaling factor when QT_AUTO_SCREEN_SCALE_FACTOR is enabled. You can set scaling to 1, 1.5, or 2. The recommended scaling factor is 1.5.

Note:  Other scaling factors may work but have not been tested.

QT_SCREEN_SCALE_FACTORS

In multi-monitor setups, sets the interface scale independently by screen using the QT_SCREEN_SCALE_FACTORS variable. Scaling uses the same recommended factors, separated by ; (semicolon). For example, QT_SCREEN_SCALE_FACTORS="1.5;1" where the first monitor is higher resolution than the second.

QT_PLUGIN_PATH

The location where Nuke looks for custom Qt libraries if you don't want to use those shipped with Nuke. Setting this environment variable adds the custom path to Nuke's Qt library paths.

TIMELINE_DISABLE_PBO_UPLOADS

When enabled, the performance benefit from using pixel buffer objects (PBO) for texture uploads from RAM to the GPU is disabled.

You can try disabling PBOs if you notice playback degradation.