Glossary

Draco Compression

Draco is Google's open-source 3D mesh compression algorithm, integrated into the glTF and GLB pipeline as the optional KHR_draco_mesh_compression extension. It typically reduces 3D model geometry to a third of the original file size with no visible quality loss, which directly improves load times for web 3D and AR. Most authoring tools and renderers, including Blender and Google's model-viewer, support Draco natively. PausAR Viewer handles Draco-encoded GLB files transparently.

Quick Facts

Developer
Google
License
Apache 2.0 (open source)
Standard
KHR_draco_mesh_compression (glTF extension)
Compression ratio
typically about one third of the original file size
Trade-off
small decode overhead at load time, usually negligible
Tool support
Blender (native export), Three.js (DracoLoader), model-viewer (automatic), gltf-transform

Draco solves the bandwidth problem of web 3D. A detailed product model can easily be 20 MB or more uncompressed, which is too much for fast loading on a mobile network. Draco compresses the geometry (vertices, normals, UVs, indices) into a form that is typically a third of the original size, sometimes smaller, without losing visual quality at typical web display sizes.

The integration is clean. Draco lives inside the glTF/GLB file as the KHR_draco_mesh_compression extension, so the model stays standards-based and works in any glTF 2.0 renderer that supports the extension. Blender, the most common authoring tool, exports Draco-compressed GLB natively: you tick a checkbox at export time. Google’s model-viewer decodes Draco automatically in the browser, and the same applies in Three.js with the DracoLoader.

For a WordPress site, the practical impact is faster load times. A 12 MB uncompressed product GLB might end up at 3 to 4 MB with Draco, and the user sees the model that much sooner. Core Web Vitals (particularly Largest Contentful Paint) benefit measurably. PausAR Viewer handles Draco-encoded GLB files transparently: once the file is uploaded, the plugin’s underlying model-viewer decodes it at runtime, with no extra setup.

Comparison

PropertyWithout DracoWith Draco
Typical file size (detailed product)10 to 20 MB3 to 7 MB
Initial load on mobile networkSlowSubstantially faster
Decode overhead in browserNoneSmall (one-time, at load)
Visible quality at web sizeOriginalNo visible loss
Renderer supportUniversalUniversal in modern glTF viewers

FAQ

Does Draco affect 3D model quality?

At typical web display sizes, no visible loss. Draco is a lossy compression algorithm tuned for 3D mesh data, with parameters that let you trade compression strength against accuracy. Default settings are designed for the web and AR use case.

Do I need to do anything to use Draco in PausAR Viewer?

No. Export your GLB from Blender with the Draco checkbox enabled, then upload it to the PausAR Viewer Elementor widget. The plugin's model-viewer renderer decodes Draco automatically.

How much can Draco shrink my GLB?

Typical reductions are to one third of the original size. The exact ratio depends on the geometry complexity and the Draco compression level. A 12 MB product GLB usually ends up at 3 to 5 MB.

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