Deep-dive into glTF file format

During recent years, the glTF file format has gained more and more prominence, due to its functionality and the wide variety of applications. Therefore, this article will explain what a glTF file consists of and how it can best be used.

 

What is a glTF file format?

glTF file format realized by SmartPixels for TAG HEUER

The very first glTF file format was developed in 2012 by COLLADA working group members. It was then made available to the general public in October 2015. The purpose was to create a file format that :

 

dealt with compact files,

 

acted quickly when loading,

 

was well-processed during runtime,

 

was capable of converting a thorough 3D scene representation.

 

glTF is the most efficient file format for 3D renderings, covering geometries, textures, and animations. However, it is still missing features for physical behavior, sounds, and interactions, which are crucial when working on complex scenes.

 

A more technical definition d' glTF file format can be explained as follows: “glTF (Graphic Language Transmission Format) is a royalty-free specification for transmitting and loading 3D scenes and models into engines and software applications. The size of 3D assets and the runtime procedure necessary for unpacking and use in applications are reduced by glTF”.

 

To enable the interoperable use of 3D content across industry applications, glTF defines a publishing format that streamlines creative workflows et interactive services.

The need for glTF, why?

3D rendering of a Paco Rabanne perfume
Augmented Reality filter for luggage

The need for efficient file formats became increasingly clear as the digital revolution progressed with its many applications. Technologies like Réalité Augmentée et virtual-try-on gained popularity, so a new file format was needed to transfer 3D data models easily.

 

Before the advent of the glTF file format, the most used file types were the FBX and the OBJ. However, both of them proved to be not as efficient, fast, and smooth as the glTF one.

 

The FBX file format was mainly exploited for its motion acquisition capabilities. Furthermore, this file typology has been widely used for its high-end modeling features. Finally, the speed et effectiveness of the FBX played a major role in its implementation. In fact, the FBX file is easy et fast to both write et read.

 

On the other hand, the OBJ file is a common 3D image format that can be exported et opened by a variety of 3D image editing software programs. OBJ files are utilized by Wavefront’s Advanced Visualizer program in order to outline and store three-dimensional objects. To illustrate, these file formats can easily encode the surface geometry d' 3D objects.

 

Although, if the purpose is to transfer 3D renderings’ software quickly and in real time, and the used platform supports a more contemporary format, glTF overperforms compared to FBX and OBJ

Which is the main exploitation of a glTF file format?

3D rendering of a Paco Rabanne perfume realized by SmartPixels (360° motion)

The glTF format, known for its low weight et superior visuals, is gaining traction as an open-source norm in 3D trade et many web services.

 

3D scenes’ depiction: glTF can compress the mesh (3D geometries) very effectively.

 

3D catalogs for e-commerce: it works flawlessly with the major 3D APIs available on Web (WebGL) and desktop (OpenGL, Vulkan ecc.).

 

Réalité Augmentée: due to of its rapidity and legibility, this format is quickly taking over as the industry standard for Augmented Reality solutions.

 

NFTs and Metaverse: glTFs have the ability to reduce the runtime process necessary for unpacking and using 3D assets in applications. For its ease of transportability, this file can be widely used for web3 applications.

glTF for Augmented Reality

Augmented Reality filter for luggage
Augmented Reality filter for luggage

Augmented Reality (AR) is an interactive experience that combines the real world with computer-generated content. AR is defined as a system that combines real and virtual realms, allows for real-time interaction , and accurately registers virtual and real objects as 3D renderings.

 

To facilitate and make Gestion des actifs 3D interoperable across applications, there has always been a considerable effort in search of shared file formats. It seems that the glTF file format might have solved these issues.

 

In terms of technology, glTF describes the 3D asset hierarchy using JSON, as well as geometries, and textures. For animations, it uses a binary payload. On the other hand, it supports textures in JPEG et PNG formats. Furthermore, it supports PBR (Physically Based Rendered) materials, which are the current most popular standard in 3D applications.

 

Because of its characteristics, its speed, and readability, this format is swiftly taking over as the industry norm for Réalité Augmentée applications. In fact, the glTF format is recommended if the need is to effectively transfer 3D scene data over the Internet for visual representation in a remote application, like Augmented Reality.

 

SmartPixels exploits glTF file formats to produce Augmented Reality solutions. Once a product’s 3D rendering has been finalized, it can be exported in a glTF file format in order to create engaging and interactive 3D experiences for our clients.

SmartPixels is an expert in the creation of photo-realistic 3D visuals and personalization experiences. Do not hesitate to contact the team to learn more!