glTF
Open standard for 3D delivery
Also known as: glb · GLB · GL Transmission Format · .gltf
Definition
glTF is an open 3D file format from the Khronos Group, often called the JPEG of 3D, designed for fast delivery and loading on the web and in apps. It stores meshes, PBR metal/roughness materials, textures, skeletons and animation, either as a .gltf file with separate resources or as a single binary .glb. It is supported by Blender, Sketchfab, Godot, web viewers and many AR tools.
In production
Use glTF or GLB to publish models to the web, share previews and exchange PBR assets, since the material travels inside the file. It uses the metal/roughness workflow, and its metallic-roughness texture keeps roughness in green and metallic in blue, so textures from Substance Painter map to it directly. For a game engine pipeline FBX is still more common, and glTF is a good second option when you want materials to travel with the model.
Tools that use glTF
See also
FBX
The standard 3D exchange format for games
USD (OpenUSD)
Scene description format for pipelines
PBR
Physically Based Rendering
Metal/Roughness vs Specular/Glossiness
The two PBR texture workflows
ORM Texture
Occlusion / Roughness / Metalness packed into one map
Textures Missing After Exporting From Blender
Model arrives in the engine without its materials
Principled BSDF
Blender's all-purpose PBR shader