What is a .gltf file?
GL Transmission Format · 3D model · Khronos Group · 2015
glTF is the modern, open standard for 3D on the web, often called the JPEG of 3D. It is compact and fast to load, carrying meshes, materials, textures and animation, and it renders directly in browsers and AR viewers.
What is a .gltf file used for?
glTF was designed for efficient delivery and quick rendering. The text .gltf form is JSON, while the binary .glb packs everything, including textures, into one file.
It supports physically based materials and animation, so a single glTF can present a fully shaded, moving model in a browser without plugins.
It is now the preferred web and AR format, with strong support in engines, viewers and phones.
What opens a .gltf file?
The .gltf format opens in the following apps, grouped by operating system. If one app does not work, try another from the same list.
Windows
- Windows 3D Viewer
- Blender
- Babylon.js Sandbox (web)
macOS
- Preview (some)
- Blender
- web viewers
Linux
- Blender
- web viewers
Web
- Browsers via WebGL viewers
Open a .gltf file step by step
- Confirm the file really is a .gltf. Drop it into the WhatFileType identifier, which reads its signature in your browser without uploading anything.
- On Windows, open it with Windows 3D Viewer or Blender.
- On Mac, use Preview (some) or Blender.
- On Linux, try Blender or web viewers.
- Still stuck? Convert the .gltf to OBJ, which opens more widely.
Why can't I open my .gltf file?
Almost always because no installed app understands glTF. Install one of the apps above, or convert the file to a format your existing software already reads. If double-clicking opens the wrong program instead of nothing at all, the file association is set to the wrong app rather than the file being broken.
The other possibility is that the file is not really a .gltf at all. Drop it into the file identifier to check it by its bytes instead of its name. Nothing is uploaded.
How to convert a .gltf file
You can convert a .gltf file to OBJ, FBX, STL using a conversion tool or the export menu of an app that opens it.
What is the .gltf file signature (magic bytes)?
A .gltf file starts with the hex bytes 67 6C 54 46, which read as glTF in ASCII. Programs identify glTF by those bytes, not by the filename, so a renamed file still gives itself away.
These are the documented signatures for glTF. For a full breakdown, see the glTF (binary GLB) file signature page.
| Hex signature | Offset | ASCII | Note |
|---|---|---|---|
| 67 6C 54 46 | 0 | glTF | 'glTF' (binary .glb) |
| 7B | 0 | { | '{' (text .gltf is JSON) |
See the full magic-numbers reference for every format.
Frequently asked questions
What is a .gltf file?
glTF is the modern, open standard for 3D on the web, often called the JPEG of 3D. It is compact and fast to load, carrying meshes, materials, textures and animation, and it renders directly in browsers and AR viewers.
What is the difference between glTF and GLB?
They are the same format. .gltf is the text (JSON) version with separate asset files, .glb packs everything into one binary file.
Related formats
Sources
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