File extension

.fbx

Autodesk FBX

.fbx files are Autodesk FBX 3D files: a proprietary format for exchanging 3D models, materials, skeletons, and animation between content creation tools and game engines.

Known meanings

Formats and reference material for .fbx

Autodesk FBX

Proprietary 3D interchange format for geometry, materials, rigs, and animation, in binary or ASCII form

  • 3d-graphics game-files
  • Autodesk (originally Kaydara)
Open link

Details

Format notes

Autodesk FBX

FBX is a 3D file format owned by Autodesk, originally created by Kaydara for its motion capture software Filmbox, which gave the format its name. Alias acquired Kaydara in 2004, and Autodesk acquired Alias in 2006. The format carries meshes, materials, texture references, cameras, lights, skeletons, skinning, blend shapes, and animation, and is widely used to move assets between tools such as Maya, 3ds Max, MotionBuilder, Blender, Unity, and Unreal Engine.

Technical Notes

FBX exists in a binary and an ASCII variant. Binary files begin with the text Kaydara FBX Binary followed by a null-padded header and a version number, with data stored as a tree of nodes holding properties. The format has had many versions, and files from newer versions are not always readable by older software. The format is proprietary and not published as an open specification; Autodesk provides the FBX SDK for reading and writing it under its own license terms. Other tools rely on this SDK or on reverse-engineered readers.

Adoption

FBX is a de facto standard in game development and animation workflows, particularly for characters and animation. Its closed nature and inconsistent implementations between tools can lead to differences in materials, units, or axis conventions, so open formats such as glTF or USD are often used for delivery.

Preservation And Security Notes

Because FBX is proprietary and versioned, archive the original authoring files in addition to FBX exports, and record the FBX version and the exporting application. As with other complex binary formats, importers can contain memory-safety bugs, so handle untrusted FBX files with up-to-date software.

Further Reading

  • Autodesk FBX SDK overview: https://aps.autodesk.com/developer/overview/fbx-sdk