Blender Web Pipeline

Blender Web Pipeline

Overview

Blender Web Pipeline skill provides workflows for exporting 3D models and animations from Blender to web-optimized formats (primarily glTF 2.0). It covers Python scripting for batch processing, optimization techniques for web performance, and integration with web 3D libraries like Three.js and Babylon.js.

When to use this skill:

• Exporting Blender models for web applications
• Batch processing multiple 3D assets
• Optimizing file sizes for web delivery
• Automating repetitive Blender tasks
• Creating production pipelines for 3D web content
• Converting legacy formats to glTF

Key capabilities:

• glTF 2.0 export with optimization
• Python (bpy) automation scripts
• Texture baking and compression
• LOD (Level of Detail) generation
• Batch processing workflows
• Material and lighting optimization for web

Core Concepts

glTF 2.0 Format

Why glTF for Web:

• Industry-standard 3D format for web
• Efficient binary encoding (.glb)
• PBR materials support
• Animation and skinning
• Extensible with custom data
• Wide library support (Three.js, Babylon.js, etc.)

glTF vs GLB:

.gltf = JSON + external .bin + external textures
.glb  = Single binary file (recommended for web)

Blender Python API (bpy)

Access Blender data and operations via Python:

import bpy

# Access scene data
scene = bpy.context.scene
objects = bpy.data.objects

# Modify objects
obj = bpy.data.objects['Cube']
obj.location = (0, 0, 1)
obj.scale = (2, 2, 2)

# Export glTF
bpy.ops.export_scene.gltf(
    filepath='/path/to/model.glb',
    export_format='GLB'
)

Web Optimization Goals

Target Metrics:

• File size: <5 MB per model (ideal <1 MB)
• Polygon count: <50k triangles for real-time
• Texture resolution: 2048x2048 max (1024x1024 preferred)
• Draw calls: Minimize via texture atlases
• Load time: <2 seconds on average connection

Common Patterns

1. Basic glTF Export (Manual)

# Blender Python Console or script

import bpy

# Select objects to export (optional - exports all if none selected)
bpy.ops.object.select_all(action='DESELECT')
bpy.data.objects['MyModel'].select_set(True)

# Export as GLB
bpy.ops.export_scene.gltf(
    filepath='/path/to/output.glb',
    export_format='GLB',                # Binary format
    use_selection=True,                 # Export selected only
    export_apply=True,                  # Apply modifiers
    export_texcoords=True,              # UV coordinates
    export_normals=True,                # Normals
    export_materials='EXPORT',          # Export materials
    export_colors=True,                 # Vertex colors
    export_cameras=False,               # Skip cameras
    export_lights=False,                # Skip lights
    export_animations=True,             # Include animations
    export_draco_mesh_compression_enable=True,  # Compress geometry
    export_draco_mesh_compression_level=6,      # 0-10 (6 recommended)
    export_draco_position_quantization=14,      # 8-14 bits
    export_draco_normal_quantization=10,        # 8-10 bits
    export_draco_texcoord_quantization=12       # 8-12 bits
)

2. Python Script for Batch Export

#!/usr/bin/env blender --background --python
"""
Batch export all .blend files in a directory to glTF
Usage: blender --background --python batch_export.py -- /path/to/blend/files
"""

import bpy
import os
import sys

# Get command line arguments after --
argv = sys.argv
argv = argv[argv.index("--") + 1:] if "--" in argv else []

input_dir = argv[0] if argv else "/path/to/models"
output_dir = argv[1] if len(argv) > 1 else input_dir + "_gltf"

# Create output directory
os.makedirs(output_dir, exist_ok=True)

# Find all .blend files
blend_files = [f for f in os.listdir(input_dir) if f.endswith('.blend')]

print(f"Found {len(blend_files)} .blend files")

for blend_file in blend_files:
    input_path = os.path.join(input_dir, blend_file)
    output_name = blend_file.replace('.blend', '.glb')
    output_path = os.path.join(output_dir, output_name)

    print(f"Processing: {blend_file}")

    # Open blend file
    bpy.ops.wm.open_mainfile(filepath=input_path)

    # Export as GLB with optimizations
    bpy.ops.export_scene.gltf(
        filepath=output_path,
        export_format='GLB',
        export_apply=True,
        export_draco_mesh_compression_enable=True,
        export_draco_mesh_compression_level=6
    )

    print(f"  Exported: {output_name}")

print("Batch export complete!")

Run batch script:

blender --background --python batch_export.py -- /models/source /models/output

3. Optimize Model for Web (Decimation)

import bpy

def optimize_mesh(obj, target_ratio=0.5):
    """Reduce polygon count using decimation modifier."""

    if obj.type != 'MESH':
        return

    # Add Decimate modifier
    decimate = obj.modifiers.new(name='Decimate', type='DECIMATE')
    decimate.ratio = target_ratio  # 0.5 = 50% of original polygons
    decimate.use_collapse_triangulate = True

    # Apply modifier
    bpy.context.view_layer.objects.active = obj
    bpy.ops.object.modifier_apply(modifier='Decimate')

    print(f"Optimized {obj.name}: {len(obj.data.polygons)} polygons")

# Optimize all selected meshes
for obj in bpy.context.selected_objects:
    optimize_mesh(obj, target_ratio=0.3)

4. Texture Baking for Web

import bpy

def bake_textures(obj, resolution=1024):
    """Bake all materials to single texture."""

    # Setup bake settings
    bpy.context.scene.render.engine = 'CYCLES'
    bpy.context.scene.cycles.bake_type = 'COMBINED'

    # Create bake image
    bake_image = bpy.data.images.new(
        name=f"{obj.name}_bake",
        width=resolution,
        height=resolution
    )

    # Create bake material
    mat = bpy.data.materials.new(name=f"{obj.name}_baked")
    mat.use_nodes = True
    nodes = mat.node_tree.nodes

    # Add Image Texture node
    tex_node = nodes.new(type='ShaderNodeTexImage')
    tex_node.image = bake_image
    tex_node.select = True
    nodes.active = tex_node

    # Assign material
    if obj.data.materials:
        obj.data.materials[0] = mat
    else:
        obj.data.materials.append(mat)

    # Select object
    bpy.context.view_layer.objects.active = obj
    obj.select_set(True)

    # Bake
    bpy.ops.object.bake(type='COMBINED')

    # Save baked texture
    bake_image.filepath_raw = f"/tmp/{obj.name}_bake.png"
    bake_image.file_format = 'PNG'
    bake_image.save()

    print(f"Baked {obj.name} to {bake_image.filepath_raw}")

# Bake selected objects
for obj in bpy.context.selected_objects:
    if obj.type == 'MESH':
        bake_textures(obj, resolution=2048)

5. Generate LOD (Level of Detail)

import bpy

def generate_lods(obj, lod_levels=[0.75, 0.5, 0.25]):
    """Generate LOD copies with decreasing polygon counts."""

    lod_objects = []

    for i, ratio in enumerate(lod_levels):
        # Duplicate object
        lod_obj = obj.copy()
        lod_obj.data = obj.data.copy()
        lod_obj.name = f"{obj.name}_LOD{i}"

        # Link to scene
        bpy.context.collection.objects.link(lod_obj)

        # Add Decimate modifier
        decimate = lod_obj.modifiers.new(name='Decimate', type='DECIMATE')
        decimate.ratio = ratio

        # Apply modifier
        bpy.context.view_layer.objects.active = lod_obj
        bpy.ops.object.modifier_apply(modifier='Decimate')

        lod_objects.append(lod_obj)

        print(f"Created {lod_obj.name}: {len(lod_obj.data.polygons)} polygons")

    return lod_objects

# Generate LODs for selected object
if bpy.context.active_object:
    generate_lods(bpy.context.active_object)

6. Export with Texture Compression

import bpy
import os

def export_optimized_gltf(filepath, texture_max_size=1024):
    """Export glTF with downscaled textures."""

    # Downscale all textures
    for img in bpy.data.images: