GLTF and GLB are two variants of the same 3D format - the GL Transmission Format developed by the Khronos Group. They store identical data (geometry, materials, PBR textures, animations, and scene hierarchy) but differ in how that data is packaged. Understanding the difference determines which variant to use in your workflow and what happens to textures when you convert GLB or GLTF to FBX or other formats.
GLTF vs GLB: What Is Actually Different
GLTF is a JSON text file (.gltf) that references external files for geometry data and textures:
- The .gltf file contains the scene structure, node hierarchy, material definitions, and metadata as human-readable JSON
- A separate .bin file contains binary geometry data (vertex positions, normals, UV coordinates, face indices)
- Texture images are stored as separate PNG or JPEG files referenced by the JSON
GLB is a binary container (.glb) that packs the JSON, binary geometry, and all texture images into a single file:
- Everything is in one file - no separate .bin or texture files needed
- The file is not human-readable but is self-contained and portable
- GLB files are typically smaller than the equivalent GLTF set due to binary encoding
| Feature | GLTF (.gltf) | GLB (.glb) |
|---|---|---|
| Format | JSON text + external files | Binary single file |
| Human readable | ✅ Yes - editable in a text editor | ❌ No - binary container |
| Textures | External files (or base64 embedded in JSON) | Bundled inside the .glb container |
| Portability | ❌ Move all files together (.gltf + .bin + textures) | ✅ Single file to move or share |
| File size | Larger (uncompressed text JSON + separate files) | Smaller (binary encoding) |
| Best use case | Development, debugging, manual JSON editing | Deployment, web viewers, AR, sharing |
For most delivery and deployment purposes - web 3D viewers, AR applications, e-commerce product visualization, sharing - use GLB. For development workflows where you need to inspect or modify the JSON structure, use GLTF.
Texture Embedding: Which Formats Bundle Textures and Which Don't
The single most common cause of missing textures when working with 3D formats is moving a file without its associated texture images. Understanding which formats embed textures and which reference them externally prevents this problem:
| Format | Texture Storage | Notes |
|---|---|---|
| GLB | ✅ Bundled internally | Textures embedded in binary container - single portable file |
| FBX | ✅ Embeddable (optional) | FBX supports embedded textures; Autoconverter embeds them by default on export |
| USD/USDZ | ✅ USDZ bundles; USD references | USDZ packages everything; USD/USDC reference external files |
| 3MF | ✅ Bundled in ZIP archive | Textures included in the 3MF package |
| GLTF | ⚠️ External by default; can be base64-embedded | Standard GLTF references separate texture files; embedded GLTF encodes textures as base64 in JSON (larger file) |
| OBJ | ❌ External only | OBJ references textures via MTL file; textures must accompany the OBJ |
| DAE (Collada) | ❌ External by default | References external image files; some tools embed as base64 |
| 3DM (Rhino) | ❌ External only | Texture images stored as separate files |
| STL | ❌ No texture support | Geometry only - no material or texture data |
When Autoconverter exports to FBX, it embeds textures directly in the FBX binary - the output FBX is self-contained with no separate texture files required.
How to Open a GLB File
GLB files can be opened in a range of tools:
- Autoconverter - opens GLB/GLTF files for viewing and conversion to OBJ, FBX, SKP, DAE, and other formats on Windows
- Windows 3D Viewer - built-in Windows application that opens GLB files for basic viewing without any installation
- Blender - File > Import > GLTF 2.0 (.glb/.gltf) to open GLB files for editing in a full 3D modeling environment
- Sketchfab - upload GLB directly for online 3D viewing and sharing
- Babylon.js Sandbox (sandbox.babylonjs.com) - free browser-based GLB viewer with material and animation inspection
- Three.js Editor (threejs.org/editor) - browser-based viewer for GLB/GLTF files
Convert GLB to FBX with Textures Using Autoconverter
Converting GLB to FBX is a three-step process in Autoconverter:
- Go to File > Open and load your .glb or .gltf file. The model loads into the 3D viewport with materials and textures visible.
- Go to File > Save As and select Filmbox FBX (*.fbx) from the format dropdown.
- Click Save. Autoconverter writes the FBX file with textures embedded - the output is a single self-contained FBX file with all material and texture data bundled internally.
The same workflow converts GLB to OBJ, SKP, DAE, STL, STEP, 3DM, USD, or any other supported format. For OBJ and DAE output, texture images are written as separate files alongside the main format file - keep them in the same folder when opening in Blender or other tools.
Common GLB/GLTF Conversion Use Cases
- GLB to FBX for Maya/3ds Max - convert GLB assets from web platforms or AR pipelines to FBX for editing in Maya, 3ds Max, or Cinema 4D with full material transfer
- GLB to FBX for Unity/Unreal Engine - while modern Unity and Unreal support GLB natively, FBX remains the standard import format for asset pipelines with animation and rig data
- OBJ/FBX/SKP to GLB for web - convert product models, architectural models, or design assets from any source format to GLB for deployment in web 3D viewers, e-commerce AR, or Sketchfab
- GLTF to GLB for deployment - convert a multi-file GLTF set to a single GLB file for simpler hosting and faster loading in web applications
Frequently Asked Questions
Is GLB better than GLTF?
Neither is inherently better - they serve different purposes. GLB is better for distribution and deployment: one file, smaller size, no missing texture risk. GLTF is better for development: human-readable JSON, easier to inspect and manually edit. For final assets going to web viewers, AR apps, or client delivery, use GLB. For development and debugging, use GLTF.
Why do textures disappear when I open a GLTF in some tools?
GLTF files reference texture images as external file paths. If the texture PNG/JPEG files are not in the same folder as the GLTF file when you open it, the textures won't load. Moving or sharing a GLTF requires moving all files together. Use GLB instead for portable sharing - all textures are embedded in the binary container.
Does converting GLB to FBX preserve all textures?
Yes. Autoconverter reads GLB texture data (which is embedded in the binary container) and writes it to the FBX file embedded internally. The output FBX carries all material and texture data from the source GLB without requiring separate image files.
Is there a free trial?
Yes. The free evaluation version of Autoconverter supports up to 10 file conversions, including GLB/GLTF import and export. The full licensed version provides unlimited conversions and batch processing.
Summary
GLTF is a multi-file text format (JSON + .bin + textures); GLB is a single binary container with everything bundled. For deployment, use GLB. For development, use GLTF. Autoconverter converts GLB and GLTF to FBX, OBJ, SKP, DAE, STL, STEP, USD, and other formats - with textures embedded in the output FBX file. Converting in the other direction (OBJ/FBX/SKP to GLB) packages the model for web 3D viewers, AR, and e-commerce.
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