Command Line Arguments#

Blender 4.1

Usage: blender [args ...] [file] [args ...]

Render Options#

-b, --background

Run in background (often used for UI-less rendering).

-a, --render-anim

Render frames from start to end (inclusive).

-S, --scene <name>

Set the active scene <name> for rendering.

-f, --render-frame <frame>

Render frame <frame> and save it.

+<frame> start frame relative, -<frame> end frame relative.
A comma separated list of frames can also be used (no spaces).
A range of frames can be expressed using .. separator between the first and last frames (inclusive).

-s, --frame-start <frame>

Set start to frame <frame>, supports +/- for relative frames too.

-e, --frame-end <frame>

Set end to frame <frame>, supports +/- for relative frames too.

-j, --frame-jump <frames>

Set number of frames to step forward after each rendered frame.

-o, --render-output <path>

Set the render path and file name. Use // at the start of the path to render relative to the blend-file.

The # characters are replaced by the frame number, and used to define zero padding.

animation_##_test.png becomes animation_01_test.png
test-######.png becomes test-000001.png

When the filename does not contain #, The suffix #### is added to the filename.

The frame number will be added at the end of the filename, eg:

blender -b animation.blend -o //render_ -F PNG -x 1 -a

//render_ becomes //render_####, writing frames as //render_0001.png

-E, --engine <engine>

Specify the render engine. Use -E help to list available engines.

-t, --threads <threads>

Use amount of <threads> for rendering and other operations [1-1024], 0 for systems processor count.

Cycles Render Options#

Cycles add-on options must be specified following a double dash.

--cycles-device <device>

Set the device used for rendering. Valid options are: CPU CUDA OPTIX HIP ONEAPI METAL.

Append +CPU to a GPU device to render on both CPU and GPU.

Example:

blender -b file.blend -f 20 -- --cycles-device OPTIX

--cycles-print-stats

Log statistics about render memory and time usage.

Format Options#

-F, --render-format <format>

Set the render format. Valid options are: TGA RAWTGA JPEG IRIS AVIRAW AVIJPEG PNG BMP HDR TIFF.

Formats that can be compiled into Blender, not available on all systems: OPEN_EXR OPEN_EXR_MULTILAYER FFMPEG CINEON DPX JP2 WEBP.

-x, --use-extension <bool>

Set option to add the file extension to the end of the file.

Animation Playback Options#

-a <options> <file(s)>

Instead of showing Blender’s user interface, this runs Blender as an animation player, to view movies and image sequences rendered in Blender (ignored if -b is set).

Playback Arguments:

-p <sx> <sy>: Open with lower left corner at <sx>, <sy>.
-m: Read from disk (Do not buffer).
-f <fps> <fps_base>: Specify FPS to start with.
-j <frame>: Set frame step to <frame>.
-s <frame>: Play from <frame>.
-e <frame>: Play until <frame>.
-c <cache_memory>: Amount of memory in megabytes to allow for caching images during playback. Zero disables (clamping to a fixed number of frames instead).

Window Options#

-w, --window-border: Force opening with borders.
-W, --window-fullscreen: Force opening in full-screen mode.
-p, --window-geometry <sx> <sy> <w> <h>: Open with lower left corner at <sx>, <sy> and width and height as <w>, <h>.
-M, --window-maximized: Force opening maximized.
-con, --start-console: Start with the console window open (ignored if -b is set), (Windows only).
--no-native-pixels: Do not use native pixel size, for high resolution displays (MacBook Retina).
--no-window-focus: Open behind other windows and without taking focus.

Python Options#

-y, --enable-autoexec: Enable automatic Python script execution.
-Y, --disable-autoexec: Disable automatic Python script execution (Python-drivers & startup scripts), (default).
-P, --python <filepath>: Run the given Python script file.
--python-text <name>: Run the given Python script text block.
--python-expr <expression>: Run the given expression as a Python script.
--python-console: Run Blender with an interactive console.
--python-exit-code <code>: Set the exit-code in [0..255] to exit if a Python exception is raised (only for scripts executed from the command line), zero disables.
--python-use-system-env: Allow Python to use system environment variables such as PYTHONPATH and the user site-packages directory.
--addons <addon(s)>: Comma separated list (no spaces) of add-ons to enable in addition to any default add-ons.

Logging Options#

--log <match>: Enable logging categories, taking a single comma separated argument. Multiple categories can be matched using a .* suffix, so --log "wm.*" logs every kind of window-manager message. Sub-string can be matched using a * prefix and suffix, so --log "*undo*" logs every kind of undo-related message. Use “^” prefix to ignore, so --log "*,^wm.operator.*" logs all except for wm.operators.* Use “*” to log everything.
--log-level <level>: Set the logging verbosity level (higher for more details) defaults to 1, use -1 to log all levels.
--log-show-basename: Only show file name in output (not the leading path).
--log-show-backtrace: Show a back trace for each log message (debug builds only).
--log-show-timestamp: Show a timestamp for each log message in seconds since start.
--log-file <filepath>: Set a file to output the log to.

Debug Options#

-d, --debug

Turn debugging on.

Enables memory error detection
Disables mouse grab (to interact with a debugger in some cases)
Keeps Python’s sys.stdin rather than setting it to None

--debug-value <value>

Set debug value of <value> on startup.

--debug-events

Enable debug messages for the event system.

--debug-ffmpeg

Enable debug messages from FFmpeg library.

--debug-handlers

Enable debug messages for event handling.

--debug-libmv

Enable debug messages from libmv library.

--debug-cycles

Enable debug messages from Cycles.

--debug-memory

Enable fully guarded memory allocation and debugging.

--debug-jobs

Enable time profiling for background jobs.

--debug-python

Enable debug messages for Python.

--debug-depsgraph

Enable all debug messages from dependency graph.

--debug-depsgraph-eval

Enable debug messages from dependency graph related on evaluation.

--debug-depsgraph-build

Enable debug messages from dependency graph related on graph construction.

--debug-depsgraph-tag

Enable debug messages from dependency graph related on tagging.

--debug-depsgraph-no-threads

Switch dependency graph to a single threaded evaluation.

--debug-depsgraph-time

Enable debug messages from dependency graph related on timing.

--debug-depsgraph-pretty

Enable colors for dependency graph debug messages.

--debug-depsgraph-uid

Verify validness of session-wide identifiers assigned to ID data-blocks.

--debug-ghost

Enable debug messages for Ghost (Linux only).

--debug-wintab

Enable debug messages for Wintab.

--debug-gpu

Enable GPU debug context and information for OpenGL 4.3+.

--debug-gpu-force-workarounds

Enable workarounds for typical GPU issues and disable all GPU extensions.

--debug-gpu-compile-shaders

Compile all statically defined shaders to test platform compatibility.

--debug-gpu-renderdoc

Enable Renderdoc integration for GPU frame grabbing and debugging.

--debug-wm

Enable debug messages for the window manager, shows all operators in search, shows keymap errors.

--debug-xr

Enable debug messages for virtual reality contexts. Enables the OpenXR API validation layer, (OpenXR) debug messages and general information prints.

--debug-xr-time

Enable debug messages for virtual reality frame rendering times.

--debug-all

Enable all debug messages.

--debug-io

Enable debug messages for I/O (Collada, …).

--debug-fpe

Enable floating-point exceptions.

--debug-exit-on-error

Immediately exit when internal errors are detected.

--debug-freestyle

Enable debug messages for Freestyle.

--disable-crash-handler

Disable the crash handler.

--disable-abort-handler

Disable the abort handler.

--verbose <verbose>

Set the logging verbosity level for debug messages that support it.

GPU Options#

--gpu-backend: Force to use a specific GPU backend. Valid options: vulkan (experimental), metal, opengl.

Misc Options#

--open-last: Open the most recently opened blend file, instead of the default startup file.
--app-template <template>: Set the application template (matching the directory name), use default for none.
--factory-startup: Skip reading the startup.blend in the users home directory.
--enable-event-simulate: Enable event simulation testing feature bpy.types.Window.event_simulate.
--env-system-datafiles: Set the BLENDER_SYSTEM_DATAFILES environment variable.
--env-system-scripts: Set the BLENDER_SYSTEM_SCRIPTS environment variable.
--env-system-python: Set the BLENDER_SYSTEM_PYTHON environment variable.
-noaudio: Force sound system to None.
-setaudio: Force sound system to a specific device. None SDL OpenAL CoreAudio JACK PulseAudio WASAPI.
-h, --help: Print this help text and exit.
/?: Print this help text and exit (Windows only).
-r, --register: Register blend-file extension for current user, then exit (Windows only).
--register-allusers: Register blend-file extension for all users, then exit (Windows only).
--unregister: Unregister blend-file extension for current user, then exit (Windows only).
--unregister-allusers: Unregister blend-file extension for all users, then exit (Windows only).
-v, --version: Print Blender version and exit.
--: End option processing, following arguments passed unchanged. Access via Python’s sys.argv.

Argument Parsing#

Arguments must be separated by white space, eg:

blender -ba test.blend

…will exit since -ba is an unknown argument.

Argument Order#

Arguments are executed in the order they are given. eg:

blender --background test.blend --render-frame 1 --render-output "/tmp"

…will not render to /tmp because --render-frame 1 renders before the output path is set.

blender --background --render-output /tmp test.blend --render-frame 1

…will not render to /tmp because loading the blend-file overwrites the render output that was set.

blender --background test.blend --render-output /tmp --render-frame 1

…works as expected.

Environment Variables#

BLENDER_USER_RESOURCES:: Top level directory for user files. (other BLENDER_USER_* variables override when set).
BLENDER_USER_CONFIG:: Directory for user configuration files.
BLENDER_USER_SCRIPTS:: Directory for user scripts.
BLENDER_USER_DATAFILES:: Directory for user data files (icons, translations, ..).
BLENDER_SYSTEM_RESOURCES:: Top level directory for system files. (other BLENDER_SYSTEM_* variables override when set).
BLENDER_SYSTEM_SCRIPTS:: Directory for system wide scripts.
BLENDER_SYSTEM_DATAFILES:: Directory for system wide data files.
BLENDER_SYSTEM_PYTHON:: Directory for system Python libraries.
OCIO:: Path to override the OpenColorIO configuration file.
TEMP:: Store temporary files here (MS-Windows).
TMPDIR:: Store temporary files here (UNIX Systems). The path must reference an existing directory or it will be ignored.