Create 3D Scene

Set up full Blender scene by code. Python API (bpy). Configure scene hierarchy, add mesh objects, make PBR materials with node shaders, position lighting and cameras, set world.

When Use

• Building reproducible 3D visualization scenes from scratch
• Automating product visualization or architectural rendering setup
• Making many scene variations by code
• Template scenes for batch rendering workflows
• Prototyping scene layouts before hand-refinement
• Plugging 3D visualization into data pipelines or reporting

Inputs

Input	Type	Description	Example
Scene specifications	Configuration	Objects, materials, lighting requirements	Product dimensions, material colors, lighting setup
Output requirements	Parameters	Resolution, render engine, quality settings	1920x1080, Cycles, 128 samples
Asset paths	File paths	External models, textures, HDRIs	/path/to/hdri.exr, product_model.obj
Camera settings	Parameters	Position, rotation, focal length, DOF	location=(7,-7,5), lens=50mm
Environment	Configuration	World shader, background, ambient settings	HDRI lighting, solid color, gradient

Steps

1. Set Up Script Structure

Make Python script with imports and structure:

#!/usr/bin/env python3
"""
Scene setup script for Blender.
Usage: blender --background --python setup_scene.py
"""

import bpy
import math
import os
from pathlib import Path

def clear_scene():
    """Remove all objects from the scene."""
    bpy.ops.object.select_all(action='SELECT')
    bpy.ops.object.delete(use_global=False)

    # Clear orphaned data
    for block in bpy.data.meshes:
        if block.users == 0:
            bpy.data.meshes.remove(block)

    for block in bpy.data.materials:
        if block.users == 0:
            bpy.data.materials.remove(block)

def main():
    clear_scene()
    # Scene setup steps follow

if __name__ == "__main__":
    main()

Got: Script structure with clear_scene() and main() functions If fail: Check Python syntax. Verify bpy import works in Blender Python env

2. Add Mesh Objects

Create primitive or imported mesh objects:

def add_objects():
    """Add mesh objects to scene."""
    # Add cube
    bpy.ops.mesh.primitive_cube_add(
        size=2.0,
        location=(0, 0, 1)
    )
    cube = bpy.context.active_object
    cube.name = "Product_Base"

    # Add sphere
    bpy.ops.mesh.primitive_uv_sphere_add(
        radius=1.0,
        segments=32,
        ring_count=16,
        location=(3, 0, 1)
    )
    sphere = bpy.context.active_object
    sphere.name = "Detail_Sphere"

    # Import external model (optional)
    # bpy.ops.import_scene.obj(filepath="model.obj")

    return cube, sphere

Got: Objects show in scene with right names and positions If fail: Check operator syntax. Verify coordinates. No naming conflicts

3. Create Materials with Node-Based Shaders

Build PBR materials using shader nodes:

def create_material(name, base_color, metallic=0.0, roughness=0.5):
    """Create a PBR material with node setup."""
    # Create material
    mat = bpy.data.materials.new(name=name)
    mat.use_nodes = True
    nodes = mat.node_tree.nodes
    links = mat.node_tree.links

    # Clear default nodes
    nodes.clear()

    # Add Principled BSDF
    node_bsdf = nodes.new(type='ShaderNodeBsdfPrincipled')
    node_bsdf.location = (0, 0)
    node_bsdf.inputs['Base Color'].default_value = base_color + (1.0,)  # Add alpha
    node_bsdf.inputs['Metallic'].default_value = metallic
    node_bsdf.inputs['Roughness'].default_value = roughness

    # Add Material Output
    node_output = nodes.new(type='ShaderNodeOutputMaterial')
    node_output.location = (300, 0)

    # Link nodes
    links.new(node_bsdf.outputs['BSDF'], node_output.inputs['Surface'])

    return mat

def apply_materials(cube, sphere):
    """Apply materials to objects."""
    # Create materials
    mat_red = create_material("RedPlastic", (0.8, 0.1, 0.1), metallic=0.0, roughness=0.4)
    mat_metal = create_material("Metal", (0.8, 0.8, 0.8), metallic=1.0, roughness=0.2)

    # Assign to objects
    if cube.data.materials:
        cube.data.materials[0] = mat_red
    else:
        cube.data.materials.append(mat_red)

    if sphere.data.materials:
        sphere.data.materials[0] = mat_metal
    else:
        sphere.data.materials.append(mat_metal)

Got: Materials show in shader editor with right node connections If fail: Check node types exist. Verify link syntax. Color values in [0,1] range

4. Set Up Lighting

Configure lights for scene:

def setup_lighting():
    """Add lights to scene."""
    # Sun light
    bpy.ops.object.light_add(
        type='SUN',
        location=(5, 5, 10)
    )
    sun = bpy.context.active_object
    sun.name = "KeyLight"
    sun.data.energy = 3.0
    sun.rotation_euler = (math.radians(45), 0, math.radians(45))

    # Area light (fill light)
    bpy.ops.object.light_add(
        type='AREA',
        location=(-4, -4, 6)
    )
    area = bpy.context.active_object
    area.name = "FillLight"
    area.data.energy = 200.0
    area.data.size = 5.0
    area.rotation_euler = (math.radians(60), 0, math.radians(-135))

    # Point light (rim light)
    bpy.ops.object.light_add(
        type='POINT',
        location=(2, -5, 3)
    )
    point = bpy.context.active_object
    point.name = "RimLight"
    point.data.energy = 500.0

Got: Three lights with right intensities and positions If fail: Tune energy values for render engine (Cycles vs EEVEE). Check rotation format

5. Position Camera

Set up camera with good framing:

def setup_camera():
    """Add and configure camera."""
    bpy.ops.object.camera_add(
        location=(7, -7, 5)
    )
    camera = bpy.context.active_object
    camera.name = "MainCamera"

    # Point camera at origin
    direction = (0, 0, 1) - camera.location
    rot_quat = direction.to_track_quat('-Z', 'Y')
    camera.rotation_euler = rot_quat.to_euler()

    # Camera settings
    camera.data.lens = 50  # Focal length in mm
    camera.data.dof.use_dof = True
    camera.data.dof.focus_distance = 10.0
    camera.data.dof.aperture_fstop = 2.8

    # Set as active camera
    bpy.context.scene.camera = camera

Got: Camera positioned with right focal length and DOF settings If fail: Use simpler rotation method if track_to fails. Verify lens units

6. Configure World Environment

Set up world shader and background:

def setup_world():
    """Configure world environment."""
    world = bpy.data.worlds['World']
    world.use_nodes = True
    nodes = world.node_tree.nodes
    links = world.node_tree.links

    # Clear default nodes
    nodes.clear()

    # Add Environment Texture (for HDRI)
    node_env = nodes.new(type='ShaderNodeTexEnvironment')
    node_env.location = (-300, 0)

    # Load HDRI if available
    hdri_path = "/path/to/hdri.exr"
    if os.path.exists(hdri_path):
        node_env.image = bpy.data.images.load(hdri_path)

    # Add Background shader
    node_bg = nodes.new(type='ShaderNodeBackground')
    node_bg.location = (0, 0)
    node_bg.inputs['Strength'].default_value = 1.0

    # Add World Output
    node_output = nodes.new(type='ShaderNodeOutputWorld')
    node_output.location = (300, 0)

    # Link nodes
    links.new(node_env.outputs['Color'], node_bg.inputs['Color'])
    links.new(node_bg.outputs['Background'], node_output.inputs['Surface'])

Got: World shader with HDRI or solid background configured If fail: Skip HDRI loading if file missing. Use Background node alone with color

7. Configure Render Settings

Set basic render params:

def setup_render_settings():
    """Configure render settings."""
    scene = bpy.context.scene

    # Render engine
    scene.render.engine = 'CYCLES'  # or 'BLENDER_EEVEE'
    scene.cycles.samples = 128
    scene.cycles.use_denoising = True

    # Output settings
    scene.render.resolution_x = 1920
    scene.render.resolution_y = 1080
    scene.render.resolution_percentage = 100

    # File format
    scene.render.image_settings.file_format = 'PNG'
    scene.render.image_settings.color_mode = 'RGBA'
    scene.render.image_settings.color_depth = '16'
    scene.render.filepath = "/tmp/render_"

Got: Render settings configured. Ready for rendering If fail: Check engine name spelling. Verify resolution values are positive ints

8. Organize Scene Hierarchy

Build collections for organization:

def organize_collections():
    """Organize objects into collections."""
    # Create collections
    col_geometry = bpy.data.collections.new("Geometry")
    col_lights = bpy.data.collections.new("Lights")
    col_cameras = bpy.data.collections.new("Cameras")

    # Link to scene
    bpy.context.scene.collection.children.link(col_geometry)
    bpy.context.scene.collection.children.link(col_lights)
    bpy.context.scene.collection.children.link(col_cameras)

    # Move objects to collections
    for obj in bpy.data.objects:
        # Unlink from main collection
        bpy.context.scene.collection.objects.unlink(obj)

        # Link to appropriate collection
        if obj.type == 'MESH':
            col_geometry.objects.link(obj)
        elif obj.type == 'LIGHT':
            col_lights.objects.link(obj)
        elif obj.type == 'CAMERA':
            col_cameras.objects.link(obj)

Got: Objects organized in named collections. Easier management If fail: Check collection already exists before creating. Handle orphaned objects

Checks

• Script runs without errors in Blender background mode
• All expected objects present in scene outliner
• Materials show right colors and properties in shader editor
• Camera positioned with objects in frame
• Lighting provides enough brightness (test render)
• World environment loads right (HDRI or background color)
• Render settings configured for output requirements
• Scene organized logically in collections
• No orphaned data blocks (materials, meshes with no users)
• Script has clear_scene() for reproducibility

Pitfalls

1. Object naming conflicts: Use unique names. Check for existing objects before creating
2. Incorrect color format: RGB values must be tuples (r, g, b, a) in [0,1] range
3. Missing alpha channel: When setting colors, include alpha: (r, g, b, 1.0)
4. Node connection errors: Verify node types have expected inputs/outputs before linking
5. Camera not active: Must set bpy.context.scene.camera = camera_object
6. Relative vs absolute paths: Use absolute paths or Path() for cross-platform compatibility
7. Units confusion: Blender uses meters by default. Camera lens in millimeters
8. Rotation formats: Use math.radians() for degree-to-radian conversion
9. Render engine differences: EEVEE and Cycles have different features and params
10. Memory leaks: Clear orphaned data blocks to stop memory buildup in batch ops

See Also

• script-blender-automation: Advanced scripting patterns for procedural modeling and batch operations
• render-blender-output: Configure rendering pipeline and execute renders
• create-2d-composition: 2D graphics composition using similar scripting approaches