Developed by Niantic Labs and popularized by the Scaniverse mobile app, the SPZ (.spz) format achieves an extraordinary $10\times$ lossless file size reduction compared to raw 3D Gaussian Splatting PLY files.
A typical 500 MB capture captured from an iPhone or drone scan compresses down to roughly 40 to 50 MB, making it suitable for mobile sharing, instant messaging, and bandwidth-constrained WebAR applications.
The Technology Behind SPZ Compression
SPZ achieves extreme compression through a multi-stage entropy coding and attribute packing pipeline:
[PLY to SPZ Encoding Architecture]
├── 1. Fractional Coordinate Quantization ──► 16-bit Fixed-Point Spatials
├── 2. Octahedral Quaternion Encoding ──► Compact 2-Component Normal Projection
├── 3. Spherical Harmonics Truncation ──► Perceptually Guided Color Packing
└── 4. Deflate / Gzip Stream Container ──► Universal Fast WebAssembly Decompression| Metric | Raw 3D Gaussian PLY | Niantic .spz | Compression Ratio |
|---|---|---|---|
| File Footprint | ~500 MB | ~45 MB | Over 90% Savings |
| Visual Fidelity | Full Float Precision | Perceptually Identical | Zero Visible Artifacts |
| Mobile Loading | 15–30 Seconds | Under 2 Seconds | Instant 4G/5G streaming |
| Compatibility | Desktop DCCs | Scaniverse, Babylon.js | Modern Web 3D Ecosystem |
Converting PLY to SPZ in Browser
- Drop your
.plyGaussian Splat into the FreeConvert3D converter. - Select SPZ as the target format.
- Click Convert & Download .SPZ for 10x smaller file sizes ready for mobile sharing.
