glTF

glTF (GL Transmission Format) is an open standard developed by the Khronos Group for the efficient transmission and loading of 3D scenes and models. It is designed to be lightweight and extensible, enabling fast parsing and minimal runtime work. The format exists as a JSON-based file (.gltf) with separate binary buffers and textures, or as a single binary container (.glb) that packages all assets together.

Core to glTF is a scene graph that describes nodes, meshes, materials, textures, skins, animations, and cameras. The default material model uses physically based rendering (PBR) shading, and the specification supports morph targets, animation, and skinning for animated characters. The format is designed to be extensible through official and community extensions that add features such as advanced materials, compression, or nonstandard lighting.

glTF has become widely adopted as a neutral 3D interchange format and as a runtime asset format for web and real-time applications. It enjoys broad support across game engines, 3D authoring tools, and web libraries, including three.js, Babylon.js, Unity, and Unreal Engine through plugins or native support.

Texture compression, binary packaging, and streaming are common advantages of glTF. The ecosystem includes many extensions, such as KHR_materials_pbrSpecularGlossiness, KHR_materials_unlit, KHR_texture_transform, and KHR_draco_mesh_compression, reflecting an emphasis on interoperability and efficient delivery for web and mobile platforms.