Technique for creating accurate 3D models from multiple photographs – uses overlapping images from different angles to reconstruct geometry and texture, widely used in film VFX for scanning locations, props, actors, and creating photorealistic digital assets.
What is Photogrammetry?
Photogrammetry is a technique for 3D reconstruction from photographs. By analyzing overlapping images from different angles, precise 3D models with geometry and textures are created.
Basic Principle
| Aspect | Description |
|---|---|
| Input | Multiple photos |
| Process | Triangulation |
| Output | 3D mesh + textures |
| Basis | Computer Vision |
Workflow
| Step | Description |
|---|---|
| 1. Capture | Take photos |
| 2. Alignment | Calculate camera positions |
| 3. Point Cloud | Generate point cloud |
| 4. Mesh | Create geometry |
| 5. Texturing | Project colors |
Applications in Film
| Area | Example |
|---|---|
| Location Scan | Digitize sets |
| Prop Scan | Capture props |
| Actor Scan | Digital Doubles |
| Vehicle | Cars, airplanes |
Capture Requirements
| Factor | Recommendation |
|---|---|
| Overlap | 60-80% between images |
| Coverage | All angles |
| Lighting | Even, diffuse |
| Sharpness | Consistent |
Equipment
| Component | Description |
|---|---|
| Camera | DSLR, Mirrorless |
| Lens | Prime lens preferred |
| Lighting | Diffuse, even |
| Targets | Reference points optional |
Capture Techniques
| Method | Application |
|---|---|
| Walk-Around | Circle objects |
| Turntable | Object rotates |
| Array | Fixed camera arrangement |
| Drone | Large locations |
Software
| Program | Type |
|---|---|
| RealityCapture | Premium |
| Metashape | Professional |
| 3DF Zephyr | Mid-range |
| Meshroom | Open Source |
RealityCapture
| Feature | Description |
|---|---|
| Speed | Very fast |
| Quality | High |
| LIDAR Integration | Yes |
| Price | Pay-per-input |
Metashape (Agisoft)
| Feature | Description |
|---|---|
| Established | Industry standard |
| Features | Comprehensive |
| Scripting | Python |
| Price | One-time purchase |
Point Cloud
| Aspect | Description |
|---|---|
| Dense Cloud | Millions of points |
| Sparse Cloud | Feature points |
| Cleaning | Manual cleanup |
| Export | PLY, LAS, XYZ |
Mesh Generation
| Parameter | Description |
|---|---|
| Polygon Count | Quality vs. performance |
| Decimation | Reduction |
| Retopology | Clean topology |
| UV Mapping | For textures |
Texturing
| Type | Description |
|---|---|
| Diffuse | Color texture |
| Normal Map | Detail preservation |
| Displacement | Geometric detail |
| Specular | Reflections |
Quality Factors
| Factor | Influence |
|---|---|
| Number of images | More = better |
| Resolution | Detail level |
| Overlap | Reconstruction quality |
| Lighting | Texture quality |
Challenges
| Problem | Solution |
|---|---|
| Reflections | Matte spray |
| Transparency | Not suitable |
| Monochromatic surfaces | Add targets |
| Movement | Stabilization |
Scan Examples
| Object | Particularity |
|---|---|
| Face | Neutral, expressions |
| Clothing | Capture wrinkles |
| Buildings | Drone + ground |
| Vehicles | All around |
Actor Scanning
| Aspect | Description |
|---|---|
| Light Stage | Controlled lighting |
| Expressions | Multiple poses |
| Textures | High-res |
| Output | Digital double |
Location Scanning
| Method | Application |
|---|---|
| Ground-Based | Interiors, details |
| Drone | Aerials, exteriors |
| Combined | Full coverage |
| LIDAR+Photo | Hybrid |
Post-Processing
| Step | Tool |
|---|---|
| Cleanup | ZBrush, Maya |
| Retopo | TopoGun, Maya |
| UV | RizomUV, Maya |
| Textures | Substance |
Integration
| Software | Workflow |
|---|---|
| Maya | Asset creation |
| Houdini | FX integration |
| Unreal | Real-time |
| Nuke | Compositing |
Photogrammetry vs. LIDAR
| Aspect | Photogrammetry | LIDAR |
|---|---|---|
| Cost | Lower | Higher |
| Textures | Integrated | Separate |
| Accuracy | Good | Very high |
| Speed | Slower | Faster |
Best Practices
| Practice | Reason |
|---|---|
| Consistent lighting | Clean textures |
| Many photos | Better reconstruction |
| RAW format | Maximum quality |
| Reference targets | Scaling |
Today
Photogrammetry is a fundamental technique in the modern VFX pipeline. From simple prop scans to complete environments, it enables the creation of photorealistic digital assets. Continuous improvements in software and hardware have democratized the technique, making it accessible for productions of all sizes.