CLI Headless Execution (+3)
CLI Headless Execution
# Run Python script headlessly (no GUI)
blender --background --python script.py
# Run with specific .blend file
blender model.blend --background --python script.py
# Render single frame
blender model.blend --background --render-output //renders/frame_ --render-frame 1
# Render animation (frames 1-250)
blender model.blend --background --render-output //renders/frame_ --render-anim
# Render specific frame range
blender model.blend --background --frame-start 1 --frame-end 100 --render-anim
# Pass custom arguments (after --)
blender --background --python script.py -- --input mesh.stl --output render.png
CLI Flags Reference
| Flag |
Purpose |
--background / -b |
Run without GUI (headless) |
--python / -P |
Execute Python script |
--python-expr |
Execute Python expression inline |
--render-output / -o |
Set render output path |
--render-frame / -f |
Render single frame |
--render-anim / -a |
Render full animation |
--frame-start / -s |
Set start frame |
--frame-end / -e |
Set end frame |
--factory-startup |
Ignore user preferences |
--addons |
Enable specific addons |
--threads |
Set thread count |
Accessing Custom Arguments in Script
import sys
# Arguments after "--" are passed to the script
argv = sys.argv
if "--" in argv:
custom_args = argv[argv.index("--") + 1:]
else:
custom_args = []
# Parse with argparse
import argparse
parser = argparse.ArgumentParser()
parser.add_argument("--input", required=True)
parser.add_argument("--output", required=True)
args = parser.parse_args(custom_args)
Complete Headless Render Pipeline
#!/usr/bin/env python3
"""Headless Blender render script for engineering visualization."""
import bpy
import sys
import argparse
def parse_args():
argv = sys.argv
custom = argv[argv.index("--") + 1:] if "--" in argv else []
parser = argparse.ArgumentParser()
parser.add_argument("--input-stl", required=True)
parser.add_argument("--output-png", required=True)
parser.add_argument("--resolution", type=int, nargs=2, default=[1920, 1080])
return parser.parse_args(custom)
def main():
args = parse_args()
# Clear scene
bpy.ops.object.select_all(action='SELECT')
bpy.ops.object.delete()
# Import geometry (Blender 4.x)
try:
bpy.ops.wm.stl_import(filepath=args.input_stl)
except AttributeError:
bpy.ops.import_mesh.stl(filepath=args.input_stl) # 3.x fallback
obj = bpy.context.selected_objects[0]
# Auto-center and scale
bpy.ops.object.origin_set(type='ORIGIN_GEOMETRY', center='BOUNDS')
obj.location = (0, 0, 0)
# Setup scene
setup_engineering_camera(distance=max(obj.dimensions) * 2)
setup_lighting()
configure_render(resolution=tuple(args.resolution))
# Render
bpy.context.scene.render.filepath = args.output_png
bpy.ops.render.render(write_still=True)
print(f"Rendered: {args.output_png}")
if __name__ == "__main__":
main()
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