Compress Gaussian Splatting PLY — Reduce File Size by 90%

Compress your 3DGS PLY files from hundreds of megabytes down to a fraction of the size. Spherical harmonics preserved.

Last updated Mar 2026

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

What You Should Know

Why Compress Your Gaussian Splatting PLY Files?

Raw Gaussian Splatting PLY files are enormous. A typical phone capture produces 400-800 MB of PLY data, and complex scenes can exceed 1 GB. This makes storage expensive, sharing impractical, and web delivery impossible. Compressing PLY to SPZ reduces file size by approximately 90% — a 500 MB PLY becomes roughly 50 MB — while preserving all the data that matters for rendering: positions, covariance, opacity, base colors, and full spherical harmonics coefficients.

How SPZ Compression Works

SPZ compression applies two techniques in sequence. First, floating-point Gaussian parameters are quantized: positions to 12 bits per axis, spherical harmonics coefficients to 8 bits, and other properties to format-specific precision levels. This quantization introduces visually imperceptible precision changes. Second, the quantized data is compressed using gzip (libz), a widely supported compression algorithm that exploits the statistical redundancy in Gaussian parameter data. The combination of quantization and compression achieves the roughly 10x size reduction.

What Data Is Preserved After Compression?

All Gaussian data is preserved: positions, scales, rotations (quaternions), opacity values, base colors, and spherical harmonics coefficients up to degree 3. The total number of Gaussians remains exactly the same — there is no culling, simplification, or removal of Gaussians during compression. The only change is reduced floating-point precision from quantization, which is visually imperceptible at normal viewing distances. If you need bit-exact preservation of the original PLY data, compression is inherently lossy and PLY remains the only option.

Typical Use Cases for PLY Compression

PLY-to-SPZ compression is most valuable in three situations. First, web embedding: a 3DGS scene captured at a real estate property or architectural site typically produces a 600 MB PLY — far too large to deliver over the web. Compressing to SPZ (60 MB) makes direct browser rendering practical. Second, storage and sharing: researchers or content creators who accumulate many PLY captures can reduce storage costs dramatically by archiving in SPZ. Third, collaboration: sharing a 50 MB SPZ file with a client or collaborator is significantly more practical than a 500 MB PLY file. SPZ is also the format natively used by Niantic Scaniverse, so SPZ-compressed files are immediately compatible with that ecosystem.

PLY vs SPZ

Feature	PLY (Input)	SPZ (Compressed)
Typical File Size	400-800 MB (raw)	40-80 MB (compressed)
Compression Ratio	Uncompressed	~90% reduction
Spherical Harmonics	Full SH (up to degree 3)	Preserved through quantization
Gaussian Count	N Gaussians	Same N Gaussians (no culling)
Web Delivery	Impractical (PLY too large)	Optimized for web
Compression Method	None	Quantization + gzip

Frequently Asked Questions

Typical compression achieves 85-92% file size reduction. A 500 MB PLY file becomes approximately 40-75 MB. The exact ratio depends on scene complexity and the number of spherical harmonics bands present. Dense scenes with high SH degree tend to compress more efficiently.

The compression applies quantization which introduces minor floating-point precision changes. In practice, the compressed output looks identical to the original at normal screen resolutions. Spherical harmonics are preserved, so view-dependent color effects remain intact. Side-by-side comparisons at typical viewing distances show no perceptible difference.

Yes. Use our SPZ to PLY converter to decompress. The round-trip (PLY to SPZ to PLY) produces a PLY file that is visually equivalent to the original, though with minor quantization differences in floating-point values.

This compressor 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 processing. For very large scenes, consider using the niantic/spz command-line tool on a machine with 16+ GB RAM.

This compressor is specifically for Gaussian Splatting PLY files, not standard mesh PLY files. 3DGS PLY files contain special properties like spherical harmonics coefficients (f_rest_*), rotations (rot_*), and scales (scale_*). If you uploaded a mesh PLY, try our mesh conversion tools instead.

SPZ achieves much better compression than SPLAT: approximately 90% reduction vs. PLY for SPZ, compared to roughly 50% for SPLAT. More importantly, SPZ preserves spherical harmonics while SPLAT discards them. If you are compressing for web delivery and your target viewers support SPZ, it is the better choice in every dimension — smaller file, preserved SH, and the emerging Khronos standard.

Step-by-Step Guides

How to Create Gaussian Splatting from Video How to Deploy Gaussian Splatting to the Web: Complete Guide How to Reduce Gaussian Splatting File Size: Compression Guide Gaussian Splatting for Real Estate: Virtual Tours & Property Marketing Best Gaussian Splatting Apps & Software in 2026: Complete Comparison