Blender DLA Point Cloud Generator¶
This work is licensed under a Creative Commons Attribution 4.0 International License.
3D Diffusion-Limited Aggregation (DLA) simulation using Blender's Geometry Nodes and Cycles rendering.
Overview¶
This tool provides a complete DLA simulation environment in Blender, featuring:
- Real-time simulation via Geometry Nodes
- Artistic flow fields for spiral, tree, coral, and vortex patterns
- Particle management with stochastic deletion and duplication
- Publication-quality rendering with Cycles GPU acceleration
- Export tools for Python analysis (NumPy, PLY, CSV formats)
Requirements¶
- Blender 4.2+ with Cycles
- GPU recommended (CUDA, OptiX, HIP, or Metal)
- Python 3.10+ (for analysis notebooks)
Quick Start¶
1. Install Blender¶
# Snap (recommended)
sudo snap install blender --classic
# Or official tarball
wget https://download.blender.org/release/Blender4.2/blender-4.2.0-linux-x64.tar.xz
tar -xf blender-4.2.0-linux-x64.tar.xz
brew install --cask blender
winget install BlenderFoundation.Blender
2. Run the Setup Script¶
- Open Blender
- Go to Scripting workspace
- Open
docs/notebooks/foundations/blender/dla_blender_setup.py - Run the script (Alt+P)
- Press Space to play the animation
3. Apply a Preset¶
In Blender's Python console:
# Apply artistic preset
apply_preset(bpy.data.objects['DLA_Seed'], 'spiral')
# Available presets:
# classic, spiral, tree, coral, vortex, turbulent, dense, sparse
Parameters¶
Basic DLA (Phase 2)¶
| Parameter | Default | Description |
|---|---|---|
| Initial Particles | 5000 | Starting particle count |
| Step Size | 0.02 | Brownian motion magnitude |
| Contact Radius | 0.03 | Sticking distance |
| Noise Scale | 2.0 | Spatial frequency of motion |
Flow Field (Phase 3)¶
| Parameter | Default | Description |
|---|---|---|
| Rotation Rate | 0.05 | Z-axis spiral (rad/frame) |
| Vertical Bias | 0.01 | Upward growth tendency |
| Radial Force | 0.005 | Expansion (+) / Contraction (-) |
| Flow Noise Scale | 0.5 | Large-scale structure frequency |
| Flow Noise Strength | 0.03 | Flow displacement magnitude |
Particle Management (Phase 4)¶
| Parameter | Default | Description |
|---|---|---|
| Deletion Probability | 0.01 | % particles deleted per frame |
| Duplication Probability | 0.005 | % particles duplicated per frame |
| Max Active Particles | 50000 | Memory limit for active particles |
| Boundary Radius | 5.0 | Delete particles beyond this distance |
Material Settings (Phase 5)¶
| Parameter | Default | Description |
|---|---|---|
| tip_threshold | 0.85 | Timepoint threshold for emission glow |
| emission_strength | 2.0 | Growth tip glow intensity |
| ao_distance | 0.1 | Ambient occlusion range |
| ao_factor | 0.5 | AO shadow strength |
Presets¶
| Preset | Description | Key Settings |
|---|---|---|
classic |
Traditional DLA | No flow field, pure brownian |
spiral |
Galaxy-like | High rotation, slight expansion |
tree |
Tree growth | Strong vertical bias, high duplication |
coral |
Coral branching | Radial expansion, moderate noise |
vortex |
Tight spiral | Very high rotation, contraction |
turbulent |
Chaotic | High noise strength |
dense |
Thick growth | Low deletion, high duplication |
sparse |
Thin branches | High deletion |
Rendering¶
GPU Configuration¶
- Edit > Preferences > System
- Cycles Render Devices: Select CUDA/OptiX/HIP/Metal
- In scene: Render Engine > Cycles, Device > GPU Compute
Material Features¶
The DLA material includes:
- Timepoint coloring: Deep blue → Cyan → Green → Yellow → White
- Growth tip emission: Recently added particles glow
- Ambient occlusion: Depth-enhancing shadows
Performance Testing¶
# Test render speeds at various sample counts
test_gpu_performance()
# Benchmark simulation speed
benchmark_simulation(frames=50)
Export Formats¶
Export point clouds for external analysis:
| Format | Extension | Description |
|---|---|---|
| NumPy | .npz |
Python analysis with all attributes |
| PLY | .ply |
Standard point cloud format |
| OBJ | .obj |
Mesh format (vertices only) |
| CSV | .csv |
Tabular format |
Quick Export¶
# Export current frame
quick_export('npz', '/tmp/dla_export.npz')
quick_export('ply', '/tmp/dla_export.ply')
# Export animation sequence
export_animation_sequence(obj, '/tmp/dla_anim/', format='npz')
Analysis Notebook¶
The included Jupyter notebook (dla_visualization.ipynb) provides:
- Interactive 3D visualization with Plotly
- Fractal dimension analysis using box-counting
- Growth pattern analysis over time
- Cross-section views (XY, XZ, YZ planes)
Fractal Dimension¶
Expected result for 3D DLA: D ≈ 2.5
dimension, scales, counts, r_squared = box_counting_dimension(positions)
print(f"Fractal dimension: {dimension:.3f}")
Batch Rendering¶
Render animations from the command line:
# Single frame
blender -b -P dla_blender_setup.py -P dla_batch_render.py -- \
--frame 100 --output /tmp/dla_frame.png
# Animation
blender -b -P dla_blender_setup.py -P dla_batch_render.py -- \
--animation --start 1 --end 250 --output /tmp/dla_frames/
File Reference¶
| File | Description |
|---|---|
dla_blender_setup.py |
Main setup script (Geometry Nodes + Material) |
dla_export.py |
Export to NumPy/PLY/OBJ/CSV |
dla_batch_render.py |
Headless batch rendering |
dla_visualization.ipynb |
Analysis and visualization notebook |
Performance Tips¶
| GPU VRAM | Max Active Particles | Spawn Rate |
|---|---|---|
| 4GB | 20,000 | 50 |
| 8GB | 50,000 | 100 |
| 12GB+ | 100,000 | 200 |
Optimization¶
- Reduce Spawn Rate if simulation lags
- Increase Deletion Probability to keep particle count stable
- Decrease Boundary Radius to remove wandering particles
Advanced Features (Phase 7)¶
After basic setup, use dla_advanced_features.py for advanced capabilities:
Multi-Seed Growth¶
import dla_advanced_features as adv
# Create multiple competing DLA structures
adv.create_multi_seed_dla(num_seeds=4, seed_arrangement='circle')
# Arrangements: circle, line, random, grid, spiral, vertical, tetrahedron
Animated Flow Fields¶
# Apply animated flow field
adv.setup_animated_flow_field(obj, animation_type='rotation_sweep')
# Types: rotation_sweep, pulsing_radial, wandering_bias,
# turbulence_wave, full_cycle, breathing
Viewport Optimization¶
# Optimize for real-time preview
adv.optimize_viewport_performance(obj, quality_level='medium')
# Levels: low (10k particles), medium (30k), high (100k)
Advanced Presets¶
# Combined presets for complex effects
adv.apply_advanced_preset(obj, 'galaxy')
# Presets: galaxy, forest, coral_reef, storm