glTF (GL Transmission Format)
glTF is an open standard for 3D scenes and models, using JSON for the scene description with external binary (.bin) and texture files. It is designed for efficient real-time rendering and is the standard for WebGL, AR/VR, and 3D commerce. The binary variant (GLB) bundles everything into one file.
MIME Type
model/gltf+json
Type
Binary
Compression
Lossless
Advantages
- + Open, royalty-free Khronos Group standard
- + Human-readable JSON scene description for debugging
- + PBR materials for physically accurate rendering
- + Supports skeletal animation, morph targets, and instancing
Disadvantages
- − Multi-file format (JSON + .bin + textures) requires bundling or GLB
- − Not suited for CAD or manufacturing — those use STEP/IGES
- − Large textures can dominate file size
When to Use .GLTF
Use glTF for real-time 3D applications, WebGL viewers, and AR content. Use the GLB variant for single-file distribution.
Technical Details
A glTF asset consists of a .gltf JSON file (scene graph, nodes, materials, animations), .bin files (vertex and index buffers), and image textures. The JSON references binary data via URI or buffer views.
History
The Khronos Group released glTF 1.0 in 2015 and glTF 2.0 in 2017. Called the 'JPEG of 3D,' it was designed as a delivery format — compact, GPU-ready, and vendor-neutral. Adoption spans three.js, Babylon.js, Unity, and Unreal Engine.