What is GLB File

GLB is a file format known as GL Transmission Format Binary. It is the binary version of the GLTF (GL Transmission Format) and is widely used for transmitting and rendering 3D models, especially on the web and mobile devices

Features of GLB File

  1. Binary Format: Unlike GLTF, which is a text-based format, GLB is a binary format. This makes the files more compact and efficient to transfer.

  2. Self-contained: A GLB file packages all relevant 3D model data—geometry, textures, materials, animations—into a single file. This simplifies model management and transmission.

  3. Efficient Transfer: Because of its binary nature, GLB file are smaller in size and load faster compared to traditional 3D model formats like OBJ and FBX, making them ideal for web and mobile applications.

  4. Web-friendly: GLB is optimized for web use, supporting fast loading and easy integration with WebGL, making it popular for interactive 3D content on websites.

GLB File Structure

The structural features of GLB make it an efficient format for transmitting 3D models. Below are the key structural characteristics of a GLB file:

  1. Binary Packaging: A GLB file uses a binary format to package all 3D data into a single file. This reduces the file size and avoids the separation of multiple files (such as .gltf, .bin, .jpg/.png) commonly seen in GLTF.

  2. File Header: The first 12 bytes of a GLB file constitute the file header, which includes:

  • Magic Number: A fixed value (glTF) that identifies the file type.
  • Version: The version of the GLB file, typically 2.
  • Total Length: The total size of the GLB file in bytes.
  1. Chunk Structure: GLB file contain multiple chunks, each with its own type and length. Common chunks include:
  • JSON Chunk: The first chunk in a GLB file, containing metadata about the model, such as the node hierarchy, material properties, and animation data. This chunk is in JSON format.
  • Binary Chunk: The second chunk typically contains the actual geometric data, like vertices, normals, and texture coordinates, as well as binary data such as texture images.

  1. Efficient Loading: The binary structure of GLB file allows for faster parsing and loading, particularly in network transmission and WebGL applications. WebGL can extract data directly from a GLB file without additional parsing steps.

  2. Cross-Platform Compatibility: The structure of GLB is designed for cross-platform compatibility, supporting various devices and browsers, making it a standard format for sharing and displaying 3D content on the web.

This structural design not only enhances file transfer and loading efficiency but also simplifies the distribution and use of 3D models.

Applications Support

  1. 3D Modeling and Animation Software:
  • Blender: An open-source 3D creation suite that can import and export GLB file.
  • Autodesk Maya: A professional 3D modeling and animation software with plugins that support GLB.
  • Autodesk 3ds Max: Similar to Maya, 3ds Max can work with GLB file through plugins.
  • Cinema 4D: A 3D software that can handle GLB file, especially for exporting 3D models.
  1. Game Engines:
  • Unity: Unity supports GLB file natively, making it easy to use GLB models in game development.
  • Unreal Engine: With plugins or converters, Unreal Engine can work with GLB file.
  1. Web-Based Tools:
  • Three.js: A popular JavaScript library for 3D graphics on the web, which supports GLB file directly.
  • Babylon.js: Another powerful JavaScript framework that allows for loading and displaying GLB models.
  • Sketchfab: An online platform that allows users to upload, view, and share 3D models, including GLB file.
  1. 3D Viewers and Converters:
  • Microsoft 3D Viewer: A built-in Windows tool for viewing 3D models, including GLB.
  • Adobe Dimension: A 3D rendering and design tool that supports GLB.
  • Khronos Group glTF Viewer: A dedicated tool by the creators of the GLTF format for viewing GLB and GLTF files.
  1. Virtual Reality and Augmented Reality (VR/AR):
  • Google ARCore: Google's AR development kit that supports GLB file for augmented reality experiences.
  • Apple ARKit: Similarly, Apple's ARKit can work with GLB models for AR applications.