Description - glTF Draco Mesh Compression Extension

The draco3dgltf package is a subset of the draco3d package, containing only features of the Draco library that are relevant to compression in the glTF file format. glTF files (.gltf, .glb) can contain Draco-compressed mesh geometry, as defined by the glTF extension KHR_draco_mesh_compression.

This library does not directly read/write glTF files, but is intended for use within tools and applications that deal with the glTF format. Examples of tools using the Draco library to apply compression to glTF files include:

Blender, glTF Transform, and glTF Pipeline.

Draco github glTF branch URL: https://github.com/google/draco/tree/gltf_2.0_draco_extension

News

Check out the README file for news about this release.

NPM Package

The code shows a simple example of using Draco encoder and decoder with Node.js. draco_encoder_node.js and draco_decoder_node.js are modified Javascript encoding/decoding files that are compatible with Node.js. draco_nodejs_example.js has the example code for usage. Here we use a Draco file as an example, but when it's used with glTF assets, the Draco file should be instead some buffer data contained in the binary data.

How to run the code:

(1) Install draco3dgltf package :

$ npm install draco3dgltf

(2) Run example code to test:

$ cp node_modules/draco3dgltf/draco_nodejs_example.js .
$ cp node_modules/draco3dgltf/bunny.drc .
$ node draco_nodejs_example.js

The code loads the Bunny model, it will first decode to a mesh and then encode it with different settings.

glTF Extension

The above example shows how to decode compressed data from a binary file. To use with glTF assets. The decoder should be applied to the data of the bufferView that belongs to a Draco extension. Please see the spec for detailed instruction on loading/exporting Draco extension.

References

Bunny model from Stanford's graphic department https://graphics.stanford.edu/data/3Dscanrep/