Gaussian Splat file formats explained: .ply, .splat, .spz, .ksplat, .sog and .rad

Which Gaussian Splat format should you use? A practical comparison of PLY, SPLAT, SPZ, KSPLAT, SOG and RAD, covering size, quality and how to open each one in your browser.

12 November 2026 · 3 min read · SpatialSense team

Gaussian Splatting is young, so its files come in several formats. They all store the same thing (a list of 3D Gaussians with position, shape, colour and opacity) but they make different trade-offs between file size, visual quality and loading speed.

Here is what each one is, and how to open it.

Quick comparison

All six open in the SpatialSense Splat Viewer: drop the file onto the page and it renders locally in your browser, with nothing uploaded.

PLY (.ply)

The standard output of the original 3D Gaussian Splatting code and most training tools (Nerfstudio, Postshot, Polycam exports and others). Each Gaussian stores its full set of properties as 32-bit floats, including spherical-harmonic coefficients for view-dependent colour. That is about 248 bytes per Gaussian at full quality.

Use it as your master copy and for editing tools. Avoid it for sharing large scenes on the web: a few million Gaussians quickly becomes hundreds of megabytes.

Note that .ply is also used for ordinary point clouds and meshes. A PLY only works as a splat if it contains Gaussian properties (scale, rotation, opacity). The viewer checks this and tells you if a file is a plain point cloud.

SPLAT (.splat)

A compact format popularised by early WebGL splat viewers. Each Gaussian is packed into 32 bytes: position, scale, an RGBA colour and a quantised rotation. It drops spherical harmonics, so reflections and sheen are flattened, but files are much smaller and very simple to stream.

Files are often sorted by importance, so the first part of a file is already a recognisable preview. The viewer uses this: our garden scene shows its first 12 MB in seconds, then refines to the full 95 MB.

SPZ (.spz)

An open-source compressed format released by Niantic. It quantises and gzip-compresses the Gaussian attributes, keeping spherical harmonics, and is typically around a tenth of the size of the equivalent PLY with very little visible loss.

Use it when you want to share a scene at near-original quality without the PLY file size. It is a good default for publishing.

KSPLAT (.ksplat)

The native format of the GaussianSplats3D library for Three.js. It supports several compression levels and optional spherical harmonics. You will mostly meet it in projects built on that library.

SOG (.sog)

PlayCanvas's compressed format, used by its SuperSplat editor. It packs Gaussian attributes into compressed images, giving very small files that are fast to download.

RAD (.rad)

The level-of-detail format of the Spark renderer. A RAD file stores the scene at several levels of detail so a viewer can show a coarse version first and refine as you look around, fetching only the parts it needs. It is the right choice for very large captures, such as a whole site or a street, where downloading everything up front would take too long.

Which format should I use?

• Archiving or editing: keep the original .ply.
• Sharing a scene on the web: .spz for quality, .splat for maximum simplicity.
• Very large scenes: convert to .rad so they stream.
• Working in a particular engine: use its native format (.ksplat, .sog).

How to open any Gaussian Splat file

1. Go to the SpatialSense Splat Viewer.
2. Drop your .ply, .splat, .spz, .ksplat, .sog or .rad file anywhere on the page, or click Open your file.
3. Drag to orbit, scroll to zoom, and open the Scene report for its size, Gaussian count and tips to make it load faster.

Your file is decoded on your own device and never uploaded.

Sharing with a team

A file on your laptop is hard to share with a client or a site team. SpatialSense hosts captures so anyone can open them by link, on any device, and adds measurement, comparison over time and BIM overlay. Read how construction teams use Gaussian Splats.