Single Server Rendering

This guide demonstrates how to automate multi-camera rendering from a single .blend file using Blender’s bpy module on Brender Cloud.

Example Files

Download Sample File
Sample Script Code (see below)

Core Script


import bpy
import os
from pathlib import Path
 
def render_cameras():
    # Get the output folder from environment variable or use default
    output_folder = os.getenv('BC_OUTPUT_PATH', '/default/output/path')
    output_path = Path(output_folder)
 
    # Find all cameras in the scene
    cameras = [obj for obj in bpy.data.objects if obj.type == 'CAMERA']
 
    if not cameras:
        print("No cameras found in scene")
        return
 
    scene = bpy.context.scene
 
    for camera in cameras:
        # Set the scene camera to the current camera
        scene.camera = camera
 
        # Build the output path for the current camera
        camera_output_path = output_path / f"{camera.name}"
        scene.render.filepath = str(camera_output_path)
 
        print(f"Rendering {camera.name} => {scene.render.filepath}")
        bpy.ops.render.render(animation=False, write_still=True)
 
if __name__ == "__main__":
    render_cameras()

Key Components Explained

1. Camera Discovery


cameras = [obj for obj in bpy.data.objects if obj.type == 'CAMERA']

Finds all camera objects in the current Blender scene.

2. Output Configuration


scene.render.filepath = str(camera_output_path)

Uses BC_OUTPUT_PATH environment variable to set render destination paths.

⚠️

Use always BC_OUTPUT_PATH for proper path handling. Your render output may be lost if you use a hardcoded path.

3. Render Execution


bpy.ops.render.render(animation=False, write_still=True)

Renders single frame for each camera with final quality settings.

Environment Variables

Default Variables

Variable	Description	Example Usage
`BC_OUTPUT_PATH`	The output folder for the current server, where rendered frames and other files are saved.	`bpy.context.scene.render.filepath = str(Path(os.getenv("BC_OUTPUT_PATH")) / "frame_####")`
`BC_SERVER_INDEX`	The index of the current server within a server array; useful for distributing tasks.	Set automatically during execution.
`BC_SERVER_ARRAY_SIZE`	Total number of servers in use; this variable is only available when more than one server is active.	Used to coordinate parallel tasks across servers.

Custom Variables

Add custom key-value pairs via the Add Env button in job configuration:

Variable	Description	Example Usage
`BC_CUSTOM_VAR`	Custom environment variable	`os.getenv('BC_CUSTOM_VAR', 'default_value')`

Custom variables should begin with BC_CUSTOM to avoid conflicts with predefined variables. They can be used to pass parameters or configuration options without modifying the script code.

Usage Steps

Upload Script

Navigate to Scripts Dashboard
Upload multi_camera_render.py

Test Script

Click on script name to access detail view
Click Test Script to run a test render
If successful, proceed to job configuration

Configure Job

Navigate to New Render
Upload your .blend file or .zip containing .blend and assets
Select multi_camera_render.py from the script dropdown
Choose 1 server for rendering (for multi-server rendering, see Multi-Server Rendering)

Launch Render

Monitor progress via Render Job Details > Click on job ID cell to view details and logs

Expected Output


# BC_OUTPUT_PATH: /app/bc_output/
/app/bc_output/
├── cam_001.png
├── cam_002.png
└── cam_003.png

This script pattern works for 1-10 cameras. For larger quantities (>20 cameras), consider multi-server rendering.

Download Output

Navigate to Render Job Details > Click on job ID cell
Click Download to retrieve rendered frames (.zip)
Zip file contains all frames rendered by the script