3D’s advancement over the past few decades has been a massive, shared effort. That’s why there’s no one size fits all solution to file formatting. As the 3D industry has advanced in many industries and areas many formats have emerged often with their specific use. Here is everything you need to know about file types and how to use them.
With more and more companies entering the 3D space and continual advancements in technology such as VR (Virtual Reality), AR (Augmented Reality), game design, VFX, and the evolution of long-standing CAD (Computer Aided Design) applications, it is only natural that new file types of surfaces to handle these different capabilities.
Generally speaking, you’ll encounter two types of formats: polygonal geometric data, and boundary representation (BREP) depending on where the geometry was originally constructed. CAD applications can output both methods of storing geometric data. To preserve the higher-level geometric information in the CAD world, you’ll encounter a separate set of file formats which also contain standard polygonal data used in 3D printing and in gaming applications. Both types of geometric definition can be complex and result in large file-sizes.
Here are some of the most common 3D file types you may encounter and when you should consider using them.
OBJ files (.obj) contain 3D geometry information. This is one of the older and most common formats you will find when exporting an object from most modeling software. This polygonal format can have a sense of scale (cm, inches etc.). Its material definition is dated compared to more modern material and shading techniques. When it comes to straight geometry export it is a solid standard to leverage.
FBX files (.fbx are like OBJ in that it contains 3D object data; however, it also contains animation data. This makes this file type most popular in film, gaming, and VFX—all industries that need complex models, materials, and animation. This file format is owned by Autodesk and supported widely in both VFX and game engines. It can retain a higher level of material definition and supports many rendering engines.
GL Transmission Format (.glTF & .glb) is a polygonal file format that serves as an open-source, royalty-free counterpart to formats like FBX. Originally created by the COLLDA working group, now this KROHON Group maintains this shared open file format for model and scene exchange. This file supports static models, animation, and moving scenes, like FBX. Developers often use this format in native web applications. As one of the more modern file formats it supports the latest methods for shading and material definition and as of the updated 2.0 version it supports the Physically Based rendering materials (PBR).
USD (Universal Scene Descriptor) is a polygonal file format developed internally by Pixar that is now open source. This extensible file format is growing in its capability via its open standards and working committee include NVIDIA, PIXAR, and ADOBE to name a few. This format represents the latest concepts for 3D models, material, and interop across several unique content creation tools. It contains geometric, material, scene, and animation data. In many ways, USD is superseding typical expectations of a file format, as it efficiently stores entire scene data.
USDZ is a proprietary format created jointly by Apple and Pixar specifically for AR. This format is used for 3D augmented reality apps on Apple devices.
The list of file formats across 3D industries is extensive. Here are some more common files you might encounter:
Image by ZUH Visuals.
Deciding which file format, you should use for your project may depend on a few factors. First, verify compatibility more than anything else. If you need to transfer 3D components between software, you don’t want to waste time exporting to a file type that won’t work.
Other considerations may include the size of the exported file. This can be especially important when developing a video game or any 3D project that has specific hardware constraints. Remember that file formats are created for specific reasons, so understanding your software and why each format is included will help you make knowledgeable decisions about every export.
Photoshop can open the following 3D formats: DAE (Collada), OBJ, 3DS, U3D, and KMZ (Google Earth).
To open a 3D file on its own in Photoshop, choose File > Open, and select the file.
To add a 3D file as a layer in an open file, choose 3D > New Layer From 3D File, and then select the 3D file. The new layer reflects the dimensions of the open file and presents the 3D model over a transparent background.
