SplatTransform - 3D Gaussian Splat Converter
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SplatTransform is an open source library and CLI tool for converting and editing Gaussian splats. It can:
📥 Read PLY, Compressed PLY, SOG, SPLAT, KSPLAT, SPZ and LCC formats
📤 Write PLY, Compressed PLY, SOG, GLB, CSV, HTML Viewer, LOD and Voxel formats
📊 Generate statistical summaries for data analysis
🔗 Merge multiple splats
🔄 Apply transformations to input splats
🎛️ Filter out Gaussians or spherical harmonic bands
🔀 Reorder splats for improved spatial locality
⚙️ Procedurally generate splats using JavaScript generators
The library is platform-agnostic and can be used in both Node.js and browser environments.
Installation
Install or update to the latest version:
npm install -g @playcanvas/splat-transform
For library usage, install as a dependency:
npm install @playcanvas/splat-transform
CLI Usage
splat-transform [GLOBAL] input [ACTIONS] ... output [ACTIONS]
Key points:
- Input files become the working set; ACTIONS are applied in order
- The last file is the output; actions after it modify the final result
- Use
nullas output to discard file output
Supported Formats
| Format | Input | Output | Description |
|---|---|---|---|
.ply |
✅ | ✅ | Standard PLY format |
.sog |
✅ | ✅ | Bundled super-compressed format (recommended) |
meta.json |
✅ | ✅ | Unbundled super-compressed format (accompanied by .webp textures) |
.compressed.ply |
✅ | ✅ | Compressed PLY format (auto-detected and decompressed on read) |
.lcc |
✅ | ❌ | LCC file format (XGRIDS) |
.ksplat |
✅ | ❌ | Compressed splat format (mkkellogg format) |
.splat |
✅ | ❌ | Compressed splat format (antimatter15 format) |
.spz |
✅ | ❌ | Compressed splat format (Niantic format) |
.mjs |
✅ | ❌ | Generate a scene using an mjs script (Beta) |
.glb |
❌ | ✅ | Binary glTF with KHR_gaussian_splatting extension |
.csv |
❌ | ✅ | Comma-separated values spreadsheet |
.html |
❌ | ✅ | HTML viewer app (single-page or unbundled) based on SOG |
.voxel.json |
❌ | ✅ | Sparse voxel octree for collision detection |
Actions
Actions can be repeated and applied in any order:
-t, --translate <x,y,z> Translate Gaussians by (x, y, z)
-r, --rotate <x,y,z> Rotate Gaussians by Euler angles (x, y, z), in degrees
-s, --scale <factor> Uniformly scale Gaussians by factor
-H, --filter-harmonics <0|1|2|3> Remove spherical harmonic bands > n
-N, --filter-nan Remove Gaussians with NaN values and most Inf values;
retains +Infinity in opacity and -Infinity in scale_*
-B, --filter-box <x,y,z,X,Y,Z> Remove Gaussians outside box (min, max corners)
-S, --filter-sphere <x,y,z,radius> Remove Gaussians outside sphere (center, radius)
-V, --filter-value <name,cmp,value> Keep Gaussians where <name> <cmp> <value>
cmp ∈ {lt,lte,gt,gte,eq,neq}
opacity, scale_*, f_dc_* use transformed values
(linear opacity 0-1, linear scale, linear color 0-1).
Append _raw for raw PLY values (e.g. opacity_raw).
-F, --decimate <n|n%> Simplify to n Gaussians via progressive pairwise merging
Use n% to keep a percentage of Gaussians
-G, --filter-floaters [size,op,min] Remove Gaussians not contributing to any solid voxel.
Evaluates each Gaussian at occupied voxel centers.
Default: size=0.05, opacity=0.1, min=0.004 (1/255)
-D, --filter-cluster [res,op,min] Keep only the connected cluster at --seed-pos.
GPU-voxelizes at coarse resolution (res world units/voxel).
Default: res=1.0, opacity=0.999, min=0.1
-p, --params <key=val,...> Pass parameters to .mjs generator script
-l, --lod <n> Specify the level of detail, n >= 0
-m, --summary Print per-column statistics to stdout
-M, --morton-order Reorder Gaussians by Morton code (Z-order curve)
Global Options
-h, --help Show this help and exit
-v, --version Show version and exit
-q, --quiet Suppress non-error output
--mem Show memory usage in progress output
-w, --overwrite Overwrite output file if it exists
-i, --iterations <n> Iterations for SOG SH compression (more=better). Default: 10
-L, --list-gpus List available GPU adapters and exit
-g, --gpu <n|cpu> Select device for SOG compression: GPU adapter index | 'cpu'
-E, --viewer-settings <settings.json> HTML viewer settings JSON file
-U, --unbundled Generate unbundled HTML viewer with separate files
-O, --lod-select <n,n,...> Comma-separated LOD levels to read from LCC input
-C, --lod-chunk-count <n> Approximate number of Gaussians per LOD chunk in K. Default: 512
-X, --lod-chunk-extent <n> Approximate size of an LOD chunk in world units (m). Default: 16
--voxel-params [size,opacity] Voxel size and opacity threshold for .voxel.json. Default: 0.05,0.1
--voxel-external-fill [size] Fill exterior voxels by dilation from seed. Default size: 1.6
--voxel-floor-fill [radius] Fill each column upward from bottom until hitting solid (runs before carve).
Optional radius (world units): only patch XZ areas surrounded by floor
within 2*radius; large empty exterior areas are left alone.
Default radius: 1.6
--voxel-carve [h,r] Carve navigable space using capsule flood fill from seed.
Default: height=1.6, radius=0.2
--seed-pos <x,y,z> Seed position for voxel processing and --filter-cluster. Default: 0,0,0
-K, --collision-mesh Generate collision mesh (.collision.glb) with voxel output
--mesh-simplify-error <n> Max geometric error for collision mesh simplification as a fraction of voxelResolution. Default: 0.08
Examples
Basic Operations
# Simple format conversion splat-transform input.ply output.csv # Convert from .splat format splat-transform input.splat output.ply # Convert from .ksplat format splat-transform input.ksplat output.ply # Convert to compressed PLY splat-transform input.ply output.compressed.ply # Uncompress a compressed PLY back to standard PLY # (compressed .ply is detected automatically on read) splat-transform input.compressed.ply output.ply # Convert to SOG bundled format splat-transform input.ply output.sog # Convert to SOG unbundled format splat-transform input.ply output/meta.json # Convert from SOG (bundled) back to PLY splat-transform scene.sog restored.ply # Convert from SOG (unbundled folder) back to PLY splat-transform output/meta.json restored.ply # Convert to standalone HTML viewer (bundled, single file) splat-transform input.ply output.html # Convert to unbundled HTML viewer (separate CSS, JS, and SOG files) splat-transform -U input.ply output.html # Convert to HTML viewer with custom settings splat-transform -E settings.json input.ply output.html
Transformations
# Scale and translate splat-transform bunny.ply -s 0.5 -t 0,0,10 bunny_scaled.ply # Rotate by 90 degrees around Y axis splat-transform input.ply -r 0,90,0 output.ply # Chain multiple transformations splat-transform input.ply -s 2 -t 1,0,0 -r 0,0,45 output.ply
Filtering
# Remove entries containing NaN and Inf splat-transform input.ply --filter-nan output.ply # Filter by opacity values (keep only splats with opacity > 0.5) splat-transform input.ply -V opacity,gt,0.5 output.ply # Strip spherical harmonic bands higher than 2 splat-transform input.ply --filter-harmonics 2 output.ply # Simplify to 50000 splats via progressive pairwise merging splat-transform input.ply --decimate 50000 output.ply # Simplify to 25% of original splat count splat-transform input.ply -F 25% output.ply
Advanced Usage
# Combine multiple files with different transforms splat-transform -w cloudA.ply -r 0,90,0 cloudB.ply -s 2 merged.compressed.ply # Apply final transformations to combined result splat-transform input1.ply input2.ply output.ply -t 0,0,10 -s 0.5
Statistical Summary
Generate per-column statistics for data analysis or test validation:
# Print summary, then write output splat-transform input.ply --summary output.ply # Print summary without writing a file (discard output) splat-transform input.ply -m null # Print summary before and after a transform splat-transform input.ply --summary -s 0.5 --summary output.ply
The summary includes min, max, median, mean, stdDev, nanCount and infCount for each column in the data.
Generators (Beta)
Generator scripts can be used to synthesize gaussian splat data. See gen-grid.mjs for an example.
splat-transform gen-grid.mjs -p width=10,height=10,scale=10,color=0.1 scenes/grid.ply -w
Voxel Format
The voxel format stores sparse voxel octree data for collision detection. It consists of two files: .voxel.json (metadata) and .voxel.bin (binary octree data).
# Generate voxel collision data from a splat file splat-transform input.ply output.voxel.json # Generate voxel data with custom resolution and opacity threshold splat-transform --voxel-params 0.1,0.3 input.ply output.voxel.json # Generate voxel data with exterior fill and carve splat-transform --voxel-external-fill --voxel-carve input.ply output.voxel.json # Generate voxel data with custom seed position and carve parameters splat-transform --seed-pos 1,0,0 --voxel-carve 2.0,0.3 input.ply output.voxel.json
Device Selection for SOG Compression
When compressing to SOG format, you can control which device (GPU or CPU) performs the compression:
# List available GPU adapters splat-transform --list-gpus # Let WebGPU automatically choose the best GPU (default behavior) splat-transform input.ply output.sog # Explicitly select a GPU adapter by index splat-transform -g 0 input.ply output.sog # Use first listed adapter splat-transform -g 1 input.ply output.sog # Use second listed adapter # Use CPU for compression instead (much slower but always available) splat-transform -g cpu input.ply output.sog
Note
When -g is not specified, WebGPU automatically selects the best available GPU. Use -L to list available adapters with their indices and names. The order and availability of adapters depends on your system and GPU drivers. Use -g <index> to select a specific adapter, or -g cpu to force CPU computation.
Warning
CPU compression can be significantly slower than GPU compression (often 5-10x slower). Use CPU mode only if GPU drivers are unavailable or problematic.
Getting Help
# Show version splat-transform --version # Show help splat-transform --help
Library Usage
SplatTransform exposes a programmatic API for reading, processing, and writing Gaussian splat data.
Basic Import
import { readFile, writeFile, getInputFormat, getOutputFormat, DataTable, processDataTable } from '@playcanvas/splat-transform';
Key Exports
| Export | Description |
|---|---|
readFile |
Read splat data from various formats |
writeFile |
Write splat data to various formats |
getInputFormat |
Detect input format from filename |
getOutputFormat |
Detect output format from filename |
DataTable, Column |
Core data structures for splat data |
combine |
Merge multiple DataTables into one |
convertToSpace |
Convert a DataTable between coordinate spaces |
processDataTable |
Apply a sequence of processing actions |
computeSummary |
Generate statistical summary of data |
sortMortonOrder |
Sort indices by Morton code for spatial locality |
sortByVisibility |
Sort indices by visibility score for filtering |
writeVoxel |
Write sparse voxel octree files |
File System Abstractions
The library uses abstract file system interfaces for maximum flexibility:
Reading:
UrlReadFileSystem- Read from URLs (browser/Node.js)MemoryReadFileSystem- Read from in-memory buffersZipReadFileSystem- Read from ZIP archives
Writing:
MemoryFileSystem- Write to in-memory buffersZipFileSystem- Write to ZIP archives
Example: Reading and Processing
import { Vec3 } from 'playcanvas'; import { readFile, writeFile, getInputFormat, getOutputFormat, processDataTable, UrlReadFileSystem, MemoryFileSystem } from '@playcanvas/splat-transform'; // Read a PLY file from URL const fileSystem = new UrlReadFileSystem(); const inputFormat = getInputFormat('scene.ply'); const dataTables = await readFile({ filename: 'https://example.com/scene.ply', inputFormat, options: { iterations: 10 }, params: [], fileSystem }); // Apply transformations const processed = processDataTable(dataTables[0], [ { kind: 'scale', value: 0.5 }, { kind: 'translate', value: new Vec3(0, 1, 0) }, { kind: 'filterNaN' } ]); // Write to in-memory buffer const memFs = new MemoryFileSystem(); const outputFormat = getOutputFormat('output.ply', {}); await writeFile({ filename: 'output.ply', outputFormat, dataTable: processed, options: {} }, memFs); // Get the output data const outputBuffer = memFs.files.get('output.ply');
Processing Actions
The processDataTable function accepts an array of actions:
type ProcessAction = | { kind: 'translate'; value: Vec3 } | { kind: 'rotate'; value: Vec3 } // Euler angles in degrees | { kind: 'scale'; value: number } | { kind: 'filterNaN' } | { kind: 'filterByValue'; columnName: string; comparator: 'lt'|'lte'|'gt'|'gte'|'eq'|'neq'; value: number } | { kind: 'filterBands'; value: 0|1|2|3 } | { kind: 'filterBox'; min: Vec3; max: Vec3 } | { kind: 'filterSphere'; center: Vec3; radius: number } | { kind: 'filterFloaters'; voxelResolution?: number; opacityCutoff?: number; minContribution?: number } // GPU | { kind: 'filterCluster'; voxelResolution?: number; seed?: Vec3; opacityCutoff?: number; minContribution?: number } // GPU | { kind: 'decimate'; count: number | null; percent: number | null } | { kind: 'param'; name: string; value: string } | { kind: 'lod'; value: number } | { kind: 'summary' } | { kind: 'mortonOrder' };
Note
filterFloaters and filterCluster require a GPU device — pass createDevice via the ProcessOptions argument to processDataTable.
Custom Logging
Configure the logger for your environment:
import { logger } from '@playcanvas/splat-transform'; logger.setLogger({ log: console.log, warn: console.warn, error: console.error, debug: console.debug, progress: (text) => process.stdout.write(text), output: console.log }); logger.setQuiet(true); // Suppress non-error output