FILE FORMAT GUIDE
What Is a GLB File?
The binary container for glTF 2.0 — the "JPEG of 3D" that powers web viewers, AR, and AI model generators.
glTF 2.0 in a single file
GLB is the binary packaging of glTF 2.0 — the GL Transmission Format standardized by the Khronos Group. A .gltf is JSON plus separate .bin buffers and image files. A .glb wraps that same payload into one binary blob: a 12-byte header, a JSON chunk describing the scene, and a BIN chunk that holds geometry, animations, and embedded textures. One file to drop, one file to share, one HTTP request to load.
That container stores mesh geometry, PBR materials (baseColor, metallic, roughness), textures, skeletal animation, morph targets, cameras, lights, and the scene hierarchy that ties them together — everything STL cannot. Khronos calls glTF the “JPEG of 3D” for a reason: it is the interchange format the web, AR, and a growing wave of AI model generators actually speak.
Where GLB files come from
If you have a GLB, it almost certainly came from one of these pipelines. The format is native to the web and to Android AR; everything else exports it because those two destinations matter.
| Source | What it exports |
|---|---|
| AI model generators (Meshy, Tripo, Rodin, Luma) | Textured GLB ready for web/AR |
| Web 3D viewers (three.js, Babylon.js, model-viewer) | Native format, loads fastest |
| Game engines (Unity, Unreal via plugin) | Scene exchange |
| AR platforms (Android SceneViewer, iOS QuickLook via USDZ) | GLB is the Android AR standard |
| 3D marketplaces (Sketchfab, Turbosquid) | Download format alongside FBX/OBJ |
What is inside a GLB
The glTF 2.0 spec is explicit about what lives in the file. Units are always meters — not a convention, a requirement — which is why a model that looks right in a web viewer can import at the wrong size in a slicer that assumes millimeters.
| Data | Stored in GLB? |
|---|---|
| Triangle/polygon mesh | Yes |
| PBR materials (baseColor, metallic, roughness) | Yes |
| Textures (embedded as images) | Yes |
| Skeletal animation, morph targets | Yes |
| Scene hierarchy, cameras, lights | Yes |
| Units | Meters (always — glTF spec mandates it) |
| Print settings, infill, supports | No — use 3MF for that |
GLB vs STL
GLB is rich: materials, textures, animation, a scene graph. STL is bare triangles. To print a GLB you must convert to STL and lose everything except geometry. That is not a converter bug; STL has nowhere to put a metallic-roughness map or a skeleton.
| GLB | STL | |
|---|---|---|
| What it is | Binary glTF 2.0 container | Raw triangle list |
| Geometry | Meshes with indexed vertices | Triangles only |
| PBR materials / textures | Yes | No |
| Animation | Skeletal, morphs, clips | No |
| Units | Meters (spec-mandated) | None — slicers assume mm |
| Typical use | Web, AR, games, AI exports | 3D-print interchange |
Use the GLB to STL converter on this site for that extraction, or the STL to GLB converter for the reverse direction. Conversion runs in the browser; the file is not uploaded. Check the bounding-box readout — glTF meters versus slicer millimeters is the usual scale surprise.
FAQ
What does GLB stand for?+
GL Binary — the binary container for glTF (GL Transmission Format). The Khronos Group maintains the glTF 2.0 specification. A .glb is the same scene graph as a .gltf, packed into one file instead of a JSON sidecar plus external buffers and images.
How do I open a GLB file?+
Any browser with three.js or model-viewer, plus Blender, Windows 3D Viewer, and (partially) macOS Preview. For a quick look without installing anything, the viewer on this site opens GLB in the browser. Parsing runs in your tab; the file is not uploaded.
Can I 3D-print a GLB?+
Not directly. Slicers want STL or 3MF. Convert with the GLB to STL page on this site — materials, textures, and animation are dropped, geometry is kept. If the mesh is not watertight, run a repair pass in the slicer before printing.
GLB vs GLTF — which should I use?+
Same format, different packaging. A .gltf is JSON plus external .bin and image files, which is easier to edit by hand. A .glb is one binary file, which is easier to share and faster to load. Most tools export .glb by default; use that unless you need to poke at the JSON.
Does GLB support animation?+
Yes — skeletal animation, morph targets, and keyframe clips. That is one reason game and web pipelines use it. STL and 3MF cannot store animation; converting a GLB to either of those keeps the rest pose (or a chosen frame) as static triangles.