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PLY to SPZ Converter — Compress Your Gaussian Splatting Scene

Reduce PLY file size by up to 90% while preserving full spherical harmonics. All in your browser.

Last updated Mar 2026

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Drag PLY (Gaussian Splatting) file here, or click to upload

What You Should Know

Why Convert PLY to SPZ?

Raw Gaussian Splatting PLY files are enormous — a 30-second phone capture can produce a 400–800 MB PLY file. SPZ compresses the same scene to 40–80 MB using quantization and gzip compression, making it practical to store, share, and embed in web applications. Critically, SPZ preserves full spherical harmonics (SH) data, so view-dependent color effects are retained after conversion. This distinguishes SPZ from SPLAT, which strips SH entirely.

What Data Is Preserved?

SPZ preserves all Gaussian positions, covariance (scale and rotation), opacity, base color, and spherical harmonics coefficients up to degree 3. The conversion applies lossy quantization to floating-point values — position is quantized to 12 bits per axis, SH coefficients to 8 bits — introducing a precision difference that is visually imperceptible at normal viewing distances. The total number of Gaussians is always preserved exactly. There is no Gaussian culling or simplification during conversion.

PLY to SPZ: The Practical Workflow

This converter is the recommended first step when you receive raw 3DGS output from a training pipeline and need to publish it. After training completes, you have a large PLY file. Convert it to SPZ here, verify the output in our SPZ Viewer, then embed the SPZ in your web application or share it with collaborators. SPZ is the format recommended by Niantic for Scaniverse exports and is aligned with the emerging Khronos 3DGS standard. Note: this converter processes Gaussian Splatting PLY files specifically. If your PLY file is a mesh (exported from Blender or MeshLab), use our mesh converter tools instead. Learn about the difference at /formats/ply-3dgs.

PLY vs SPZ
FeaturePLYSPZ
File SizeLarge — uncompressed (~236 bytes/Gaussian)Very small — ~10% of equivalent PLY
Spherical HarmonicsYes — full SH up to degree 3Yes — preserved through gzip compression
Web CompatibilityLimited — size makes direct delivery impracticalExcellent — Khronos/Niantic standard
CompressionNone — raw parameter storageExcellent — quantization + gzip (~90% vs PLY)
Progressive LoadingNoNo
Typical UseResearch, desktop editing, source of truthWeb delivery, archiving, Scaniverse, long-term storage
Frequently Asked Questions
Typical compression ratios are 85–92% reduction. A 500 MB PLY file becomes approximately 40–75 MB SPZ. The exact ratio depends on scene complexity and spherical harmonics degree. Scenes with sparse Gaussians or low SH degree compress less than dense, high-SH scenes.
SPZ uses quantization, which introduces minor floating-point precision changes. In practice, this is visually imperceptible — the render looks identical to the original at normal screen resolutions. Spherical harmonics are preserved, so view-dependent color effects remain intact. If you need lossless storage, PLY is the only option.
Yes. Use our SPZ to PLY converter. The round-trip (PLY → SPZ → PLY) produces a PLY file that is visually equivalent to the original, with minor quantization differences in floating-point precision.
This converter supports PLY files up to 200 MB on desktop browsers. Files larger than 200 MB require more memory than most browsers can allocate for WebAssembly. For very large scenes, convert on a machine with 16+ GB RAM using the niantic/spz command-line tool.
Yes. SPZ was developed by Niantic and is the native export format of their Scaniverse app. SPZ files produced by this converter are fully compatible with Niantic's tooling.

Related Converters

PLY to SPLATPLY to KSPLATSPLAT to PLYSPLAT to KSPLATSPLAT to SPZKSPLAT to PLYKSPLAT to SPLATKSPLAT to SPZSPZ to PLYSPZ to SPLATSPZ to KSPLAT

Step-by-Step Guides

Gaussian Splatting for Beginners: Convert and View PLY Files OnlineSPZ Format: Technical Guide to Compressed Gaussian SplattingGaussian Splatting in Unity and Unreal Engine: Complete WorkflowWhat Is 3D Gaussian Splatting? The Technology Replacing NeRFGaussian Splatting Tutorial: From Photos to Interactive 3D SceneHow to Create Gaussian Splatting from Photos: Capture GuideHow to Create Gaussian Splatting from Video3D Gaussian Splatting Software Comparison (2026)Gaussian Splatting in Blender: Complete Import, Edit & Render Workflow