File extension

.gltf

glTF (GL Transmission Format)

.gltf and .glb files are glTF (GL Transmission Format) assets: a modern, runtime-oriented 3D format for efficiently delivering scenes and models — geometry, materials, textures, animation, and PBR shading — to engines and the web.

Known meanings

Formats and reference material for .gltf

glTF (GL Transmission Format)

Royalty-free runtime 3D asset format for scenes and models, with JSON (.gltf) and binary (.glb) forms

  • 3d-graphics internet
  • The Khronos Group
Open link

Details

Format notes

glTF (GL Transmission Format)

glTF is a modern 3D asset format from the Khronos Group, often described as “the JPEG of 3D,” designed for the efficient transmission and runtime loading of 3D scenes and models. Unlike authoring/interchange formats aimed at editing, glTF is optimized to be loaded directly by engines and browsers: its structure maps closely onto how GPUs and real-time renderers consume data, minimizing the work an application must do at load time.

A glTF asset describes a full scene graph: nodes with transforms, meshes, materials using physically based rendering (PBR), textures, cameras, skins for skeletal animation, and keyframe animations. It comes in two serializations. The .gltf form is a JSON document that references external binary buffers (.bin) and image files, while the .glb form packs the JSON, binaries, and textures into a single self-contained binary file — convenient for distribution. An extension mechanism lets vendors and the community add features (such as compression or advanced materials) without breaking the core.

Adoption

glTF 2.0 is widely supported across game engines, 3D web frameworks, model viewers, AR/VR platforms, and content pipelines, making it a common target for delivering 3D content to end users. The media types are model/gltf+json for .gltf and model/gltf-binary for .glb.

Preservation And Security Notes

glTF is open, documented, and (in JSON form) partly human-readable, which suits it for interchange and archiving of runtime assets; keep external buffers and textures with a .gltf, or prefer the self-contained .glb. As a format that references external resources and carries binary buffers, a loader handling untrusted assets should validate buffer and accessor bounds and constrain external and data-URI fetches.

Further Reading

  • glTF overview (Khronos): https://www.khronos.org/gltf/
  • glTF 2.0 specification: https://registry.khronos.org/glTF/specs/2.0/glTF-2.0.html