Blender CLI

Blender CLI

3D creation suite with full command-line interface. Render scenes, batch process, and run Python scripts headlessly.

• Official site: https://www.blender.org
• Docs: https://docs.blender.org/manual/en/latest/advanced/command_line/arguments.html

Common Commands

Rendering

blender -b scene.blend -o /tmp/frame_ -f 1                    # Render frame 1
blender -b scene.blend -o /tmp/frame_ -s 1 -e 250 -a          # Render animation (frames 1-250)
blender -b scene.blend -o /tmp/render.png -f 1 -F PNG          # Render as PNG
blender -b scene.blend -o /tmp/render_ -F OPEN_EXR -a          # Render as OpenEXR

Engine Selection

blender -b scene.blend -E CYCLES -f 1                          # Render with Cycles
blender -b scene.blend -E BLENDER_EEVEE_NEXT -f 1              # Render with EEVEE

Resolution

blender -b scene.blend -o /tmp/out -x 1920 -y 1080 -f 1       # Custom resolution

Python Scripting

blender -b --python script.py                                   # Run Python script
blender -b scene.blend --python script.py                       # Run script on file
blender -b --python-expr "import bpy; print(bpy.data.objects.keys())"  # Inline Python

File Conversion

# Import/export via Python script
blender -b --python-expr "
import bpy
bpy.ops.wm.read_factory_settings(use_empty=True)
bpy.ops.import_scene.fbx(filepath='model.fbx')
bpy.ops.wm.save_as_mainfile(filepath='model.blend')
"

# Export to glTF
blender -b model.blend --python-expr "
import bpy
bpy.ops.export_scene.gltf(filepath='model.glb', export_format='GLB')
"

Scene Info

blender -b scene.blend --python-expr "
import bpy
for obj in bpy.data.objects:
    print(f'{obj.name}: {obj.type}')
"

Agent Best Practices

• Always use -b (background) flag for headless/CLI operation
• Use -o to set output path, -f for single frame, -a for animation
• Use --python or --python-expr for automation and batch processing
• Use -F to set output format: PNG, JPEG, OPEN_EXR, FFMPEG
• CYCLES is higher quality but slower; EEVEE is faster for previews
• Use --python-text to run a text block already in the .blend file
• Check Blender's Python API docs for scripting: https://docs.blender.org/api/current/

Example Workflows

Batch render a scene

blender -b scene.blend -E CYCLES -o /tmp/renders/frame_ -s 1 -e 100 -a

Convert FBX to glTF

blender -b --python-expr "
import bpy
bpy.ops.wm.read_factory_settings(use_empty=True)
bpy.ops.import_scene.fbx(filepath='input.fbx')
bpy.ops.export_scene.gltf(filepath='output.glb', export_format='GLB')
"