model/gltf-binary MIME Type
MIME type details for model/gltf-binary
In active use| MIME type | model/gltf-binary |
|---|---|
| Extensions | .glb |
| Magic number | 67 6C 54 46 |
| First standardized | 2017 |
| Created by | Khronos Group |
| Browser support | Chrome, Edge, Firefox, Safari |
| Example applications | Blender, Khronos glTF Sample Viewer |
| Poly support | Yes. Poly recognizes Binary glTF scenes and makes their supported geometry and scene metadata available in the file experience. |
| Indexed by Poly | Yes. Poly indexes filenames and creates visual similarity information for supported 3D content; available scene metadata is shown in details. |
| Preview in Poly | Yes. Poly previews supported GLB geometry and scene content. |
| Poly agent | Yes. An optimized rendition of the 3D object or scene is provided to the agent, allowing compact yet information-rich multimodal interaction with 3D files. |
What does model/gltf-binary represent?
model/gltf-binary is the registered media type for Binary glTF, normally stored as .glb. The GLB header uses the little-endian magic value 0x46546C67, displayed in file order as 67 6C 54 46. A JSON chunk describes the scene, and a BIN chunk can carry the buffers used by meshes, skins, and animation.1
The container can include image data, but external resources are still allowed. A valid signature is only an initial identification check. Applications must validate chunk lengths, JSON, buffer ranges, and referenced resources before rendering.
Opening and converting Binary glTF
Blender documents import and export for glTF 2.0, including GLB.2 The Khronos glTF Sample Viewer provides a browser-based conformance-oriented view of sample assets.3 Export to .gltf when a readable JSON description and separate resources are more useful. Export to GLB when a single binary delivery file is easier to distribute.
Support in Poly
Poly previews supported geometry, makes the filename searchable, and provides visual similarity for supported 3D content. Available mesh, node, material, vertex, triangle, camera, light, and animation counts appear as metadata when present. An optimized rendition of the 3D object or scene is provided to the agent, allowing compact yet information-rich multimodal interaction with 3D files.
| Construct | Verified handling |
|---|---|
| Meshes, nodes, and materials | Supported when valid glTF data is present |
| Textures | Supported when usable image resources are available |
| Cameras and lights | Point, spot, and directional lights are supported; area-light behavior is approximate |
| Skins and animation | Supported when represented; individual extension behavior can vary |
Poly's view is an inspection and understanding surface. It does not replace Blender or another authoring application for editing, rigging, or exact export validation.
Format context and alternatives
Khronos designed glTF for efficient runtime delivery of 3D scenes. Binary glTF keeps the same scene model while reducing the number of separately managed delivery resources.1 .gltf is the natural companion when JSON and external resources should remain visible. STL is useful for simple triangle surfaces, while 3MF targets additive manufacturing.
Footnotes
- Khronos Group. glTF 2.0 Specification. ↩ ↩2
- Blender Manual. glTF 2.0 importer and exporter. ↩
- Khronos Group. glTF Sample Viewer. ↩