Content pipeline tools for optimizing glTF assets by Richard Lee and the Cesium team.
Supports common operations including:
- Converting glTF to glb (and reverse)
- Saving buffers/textures as embedded or separate files
- Converting glTF 1.0 models to glTF 2.0
- Applying Draco mesh compression
gltf-pipeline can be used as a command-line tool or Node.js module.
Install Node.js if you don't already have it, and then:
npm install -g gltf-pipeline gltf-pipeline -i model.gltf -o model.glb
gltf-pipeline -i model.gltf -b
gltf-pipeline -i model.glb -o model.gltf
gltf-pipeline -i model.glb -j
gltf-pipeline -i model.gltf -o modelDraco.gltf -d
gltf-pipeline -i model.gltf -t
const gltfPipeline = require("gltf-pipeline"); const fsExtra = require("fs-extra"); const gltfToGlb = gltfPipeline.gltfToGlb; const gltf = fsExtra.readJsonSync("./input/model.gltf"); const options = { resourceDirectory: "./input/" }; gltfToGlb(gltf, options).then(function (results) { fsExtra.writeFileSync("model.glb", results.glb); });const gltfPipeline = require("gltf-pipeline"); const fsExtra = require("fs-extra"); const glbToGltf = gltfPipeline.glbToGltf; const glb = fsExtra.readFileSync("model.glb"); glbToGltf(glb).then(function (results) { fsExtra.writeJsonSync("model.gltf", results.gltf); });const gltfPipeline = require("gltf-pipeline"); const fsExtra = require("fs-extra"); const processGltf = gltfPipeline.processGltf; const gltf = fsExtra.readJsonSync("model.gltf"); const options = { dracoOptions: { compressionLevel: 10, }, }; processGltf(gltf, options).then(function (results) { fsExtra.writeJsonSync("model-draco.gltf", results.gltf); });const gltfPipeline = require("gltf-pipeline"); const fsExtra = require("fs-extra"); const processGltf = gltfPipeline.processGltf; const gltf = fsExtra.readJsonSync("model.gltf"); const options = { separateTextures: true, }; processGltf(gltf, options).then(function (results) { fsExtra.writeJsonSync("model-separate.gltf", results.gltf); // Save separate resources const separateResources = results.separateResources; for (const relativePath in separateResources) { if (separateResources.hasOwnProperty(relativePath)) { const resource = separateResources[relativePath]; fsExtra.writeFileSync(relativePath, resource); } } });If a resourceDirectory is not specified, the only possible paths in a glTF object are absolute. In the event processGltf is called without a resourceDirectory and the glTF references absolute paths, it will behave as if allowAbsolute is true, but also emit a warning if it's not. To get rid of this warning, add allowAbsolute: true to your options, e.g.,:
const options = { /*... */ }; const results = await processGltf(gltf, options);should be changed to:
const options = { allowAbsolute: true, /*... */ }; const results = await processGltf(gltf, options);| Flag | Description | Required |
|---|---|---|
--help, -h | Display help | No |
--input, -i | Path to the glTF or glb file. | ✅ Yes |
--output, -o | Output path of the glTF or glb file. Separate resources will be saved to the same directory. | No |
--binary, -b | Convert the input glTF to glb. | No, default false |
--allowAbsolute, -a | Allow glTF files to refer to file URLs outside of their source path | No, default false |
--json, -j | Convert the input glb to glTF. | No, default false |
--separate, -s | Write separate buffers, shaders, and textures instead of embedding them in the glTF. | No, default false |
--separateTextures, -t | Write out separate textures only. | No, default false |
--stats | Print statistics to console for output glTF file. | No, default false |
--keepUnusedElements | Keep unused materials, nodes and meshes. | No, default false |
--keepLegacyExtensions | When false, materials with KHR_techniques_webgl, KHR_blend, or KHR_materials_common will be converted to PBR. | No, default false |
--draco.compressMeshes, -d | Compress the meshes using Draco. Adds the KHR_draco_mesh_compression extension. | No, default false |
--draco.compressionLevel | Draco compression level [0-10], most is 10, least is 0. A value of 0 will apply sequential encoding and preserve face order. | No, default 7 |
--draco.quantizePositionBits | Quantization bits for position attribute when using Draco compression. | No, default 11 |
--draco.quantizeNormalBits | Quantization bits for normal attribute when using Draco compression. | No, default 8 |
--draco.quantizeTexcoordBits | Quantization bits for texture coordinate attribute when using Draco compression. | No, default 10 |
--draco.quantizeColorBits | Quantization bits for color attribute when using Draco compression. | No, default 8 |
--draco.quantizeGenericBits | Quantization bits for skinning attribute (joint indices and joint weights) and custom attributes when using Draco compression. | No, default 8 |
--draco.unifiedQuantization | Quantize positions of all primitives using the same quantization grid. If not set, quantization is applied separately. | No, default false |
--draco.uncompressedFallback | Adds uncompressed fallback versions of the compressed meshes. | No, default false |
--baseColorTextureNames | Names of uniforms that should be considered to refer to base color textures when updating from the KHR_techniques_webgl extension to PBR materials. | No. (The defaults are not specified here) |
--baseColorFactorNames | Names of uniforms that should be considered to refer to base color factors when updating from the KHR_techniques_webgl extension to PBR materials. | No. (The defaults are not specified here) |
Run the tests:
npm run test To run ESLint on the entire codebase, run:
npm run eslint To run ESLint automatically when a file is saved, run the following and leave it open in a console window:
npm run eslint-watch Some functionality of gltf-pipeline is used by CesiumJS as a third party library. The necessary files can be generated using:
npm run build-cesium This will output a portion of the gltf-pipeline code into the dist/cesium folder for use with CesiumJS in the browser. Copy the files into Source/Scene/GltfPipeline/ in the cesium repository and submit a pull request.
Coverage uses nyc. Run:
npm run coverage For complete coverage details, open coverage/lcov-report/index.html.
The tests and coverage covers the Node.js module; it does not cover the command-line interface, which is tiny.
To generate the documentation:
npm run jsdoc The documentation will be placed in the doc folder.
Pull requests are appreciated! Please use the same Contributor License Agreement (CLA) and Coding Guide used for Cesium.