SPZ to PLY Converter — Decompress for Full Editing Access
Convert compressed SPZ files back to PLY for use in desktop 3DGS editing and research tools.
Last updated Mar 2026
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Drag SPZ file here, or click to upload
What You Should Know
Why Convert SPZ to PLY?
SPZ is optimized for storage and web delivery, but many 3DGS editing and research tools work exclusively with PLY. If you have received an SPZ file (for example, from Niantic Scaniverse or a collaborator) and need to fine-tune the scene in a desktop tool, retrain from the Gaussian parameters, or load it into a research pipeline that expects PLY, converting SPZ to PLY restores full compatibility. The PLY output contains all Gaussian parameters in the standard format expected by the official 3D Gaussian Splatting viewer.
What the Decompression Recovers
SPZ to PLY conversion reconstructs all original Gaussian parameters: position, scale, rotation (as quaternion), opacity, base color, and spherical harmonics up to degree 3. Because SPZ uses quantization, there is a minor floating-point precision difference from the original PLY — position values are quantized to 12-bit precision. In practice, this is visually imperceptible. If you need exact bit-for-bit reconstruction of the original PLY, no compressed format can provide that; SPZ gives you the closest approximation.
File Size After Decompression
SPZ is about 10x smaller than PLY. Converting back to PLY expands the file to its original size — a 50 MB SPZ will produce approximately 500 MB of PLY. Ensure you have adequate storage space before converting very large SPZ files. The output PLY uses the same property layout as standard 3DGS training output (x, y, z, nx, ny, nz, f_dc_0..2, f_rest_0..44, opacity, scale_0..2, rot_0..3). Note: the resulting PLY is a Gaussian Splatting PLY, not a mesh PLY. It will not open correctly in standard Blender mesh import. To learn more about the two types of PLY files, see /formats/ply-3dgs.
SPZ vs PLY
| Feature | SPZ | PLY |
|---|---|---|
| File Size | Very small — ~10% of equivalent PLY | Large — uncompressed (~236 bytes/Gaussian) |
| Spherical Harmonics | Yes — preserved through gzip compression | Yes — full SH up to degree 3 |
| Web Compatibility | Excellent — Khronos/Niantic standard | Limited — size makes direct delivery impractical |
| Compression | Excellent — quantization + gzip (~90% vs PLY) | None — raw parameter storage |
| Progressive Loading | No | No |
| Typical Use | Web delivery, archiving, Scaniverse, long-term storage | Research, desktop editing, source of truth |