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glTF vs FBX: their 5 key features

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In this article we will help you understand the differences of glTF vs FBX file formats for 3D models. 
In a world where brands are becoming ever-more keen on using 3D rendering techniques for their product visuals. They analyzed the benefits they would perceive from it and concluded it was worth it.
However, there are no immagini 3D on a website without the modeling phase that comes first. What are the differences and similarities between the two most used 3D models storing file formats?
This is a recurring question that deserves an answer. So, if you are looking to take your digitization further but do not know how to start, we will give you 5 key aspects you should be aware of, of both file formats. 

glTF vs FBX: definitions

On one hand, FBX stands for FilmBox, the original name of the software that later became Autodesk MotionBuilder. Therefore, FBX is a closed-sourced file format that was originally developed by Autodesk for motion capture tools. The file format was commonly used for 3D computer graphics and animation.
FBX is mostly used to exchange 3D data between software applications such as Unity, Unreal Engines, or even Autodesk Maya.
On the other hand, glTF stands for Graphics Library Transmission Format. It was initially developed by the Khronos group and more specifically the COLLADA group. It is an open-sourced format frequently used for its balance between file size and runtime performance. 
glTF is mostly used today for purposes such as transferring 3D data and integration in web browsers.
Overall, both formats are used in different industries for realistic representations of products in 3D. However, there are some distinctions to be taken into account as well. 

glTF vs FBX: 2 common grounds

Augmented Reality visualization of a Glotbe-Trotter suitcase

1. Quickness and efficiency of both formats

Both formats store the data they collect through binary coding. This enables smoother and easier reading of the file. 
Specifically, concerning the glTF format, the JSON (JavaScript Object Notation) descriptor file is used as a guide. It enables the developer to read and write the format in a relatively simple way. The same applies to FBX but with the SDK (software development kit). 
For example, it is easier and faster to read a glTF, and/or FBX than OBJ file formats. As OBJ stores data about geometry in bulk text for human comprehension, the time to read the file is extended.  
Furthermore, binary code is more compact than bulk text. As such, the glTF file format is less voluminous than an OBJ format. 

2. Data that provides rich scenes

Another advantage shared by both formats is the storage of data from rich scenes. The files store information such as models, material, animation, data, bones, scene hierarchy skinning, and lights (with an extension). Both formats are able to support animated and static images. Thus, highly complicated images are not a problem for both file formats.    

3 key aspects unique to FBX

1. Closed format

A very specific characteristic of the FBX format is that it is close-sourced. In other words, it is only possible to access the file through an SDK (Software Development kit) that is official to FBX.
Furthermore, it is impossible for an outside user to modify the format. Indeed, updates, advancements, or any change to the FBX structure, features, capabilities, and much more can only be undertaken by the owner of the file format.
However, the FBX SDK is quite powerful, and importing or exporting FBX files is made easier. Therefore, the developer using the SDK cannot see the complexity behind FBX. Also, the file format is always supported by the FBX SDK as it is the official SDK for the format. 
In addition, the SDK will always read the old and newest versions of the FBX format. 

2. Storage of a wide range of features

A very specific characteristic of the FBX format is that it is close-sourced. In other words, it is only possible to The format is known to support a wide variety of data such as: 
Position data: refers to the coordinates of points in a 3D space. Thanks to this piece of information, it is possible to define and redefine the shapes and structures of a 3D modeling process.

UV data: used to implement or map textures rendered in 2D onto 3D models. Using the coordinates of specific points on a 3D model, the textures can be efficiently and accurately applied to the model.

Normal data: this data stores the information specific to the direction that each surface faces. This is particularly useful to determine the lighting on a model and how each part of the model will interact or react to the light. 
Overall, this feature of the format allows developers to use high-quality modeling tools and highly complicated division features on the 3D models.  
Nevertheless, because of such a big capacity for complex data storage, the models may be harder to load onto video game engines for example as all topologies are not unified and are done so in the process.  

3. FBX: a qualitative older existing format

Because FBX is an older format, some of its features are not up to date and others are not used today.  As a result, some of these features can be a downside to the file format.
For example, vintage surfaces and curves: FBX also supports NURBS surfaces and curves. This represents a slight downside to the format as it is more difficult for the format to support this kind of data. Moreover, the complexity of its integration makes it harder to integrate in applications that restrict the size of files. 

Nevertheless, this feature does not affect its performance nor the preference for an FBX format for highly qualitative 3D visuals of brands’ products. 

3 key aspects unique to glTF

1. Augmented Reality

Today whether it is web or application-based, Realtà Aumentata is a pressing matter that intrigues more than one. 

In fact, glTF has become the standard format to use when implementing Realtà Aumentata onto software or websites.  This is due to their rapidity and efficiency, their readability by game engines, and their monitoring by groups. 

With the increasing request for Realtà Aumentata, the optimal format would therefore be glTF. As it is a demanding opportunity for businesses it is better to use the right file format that will guarantee the best use of its features. 

2. AR pro features with glTF

As the glTF format is used for AR, the features that enable it to be converted as such are:
Fast to read for game engines: glTF is extremely fast to read for game engines compared to FBX. The game engine can read the file data from the high-speed memory that stores the necessary data for rendering images, and videos and display them as well (GPU or VRAM). 
Follow-ups: il glTF format is followed by Standards Groups. Therefore, the file format can evolve thanks to a party other than the owner of the file. This enables the format to follow technological advances and always be up to date with the latest technological trends.

Standards Groups

Standard Groups are organizations that establish standards for different industries. In the case of the glTF format, the Standards Groups make sure that the format is updated to further its growth.
Paco Rabanne glTF file format

3. Simplistic storage

Similar to the FBX format, glTF has a quite simplistic storage model. However, the features in both cases differ. Therefore, the glTF format is less practical when storing data.
glTF stores the data under a unified typology. This enables a higher speed when game engines intend to read the file. However, it means that UV, positions, and normal data may not have differing typologies. Thus, it is harder to edit the 3D model inside the file. Therefore, if you wish to later edit your 3D model, glTF is not the best option as it is difficult to do so with this file format. 

Moreover, glTF does not support shader networks which reduces its material complexity. Today the use of such a feature is important to produce high-quality 3D visuals. Thus, lacking this feature is an important aspect to consider when making the decision of which format to choose.  

To conclude on glTF vs FBX

In this article we explained the differences of glTF vs FBX formats but also analyzed their similarities. Indeed, the formats converge in certain ways. However, it is necessary to carefully choose the file that best suits your situation.
Overall, FBX file formats are optimal for hyper-realistic renderings of your products. However, glTF is more commonly used to turn your product’s immagini 3D into Realtà Aumentata. That being said, they are both quick and efficient in their own way. Finally, the consequences of drawbacks of such file formats must be nuanced, taking into account the array of tools to which we have access today. 
If even by reading this article you are still wondering “glTF vs FBX, which one should I choose?”, let SmartPixels help you.