Animation File Formats for Game Developers
Motion capture animation data is distributed in several file formats. Choosing the wrong format means hours of troubleshooting. Here is what each format is, what tools support it, and which one you should be using for your pipeline.
FBX (Filmbox)
FBX is the universal standard for game development pipelines. Developed by Autodesk, FBX stores a full scene: skeletal hierarchy, mesh data, materials, blend shapes, and animation sequences. It is the native exchange format for Unreal Engine 5, Unity, Maya, 3ds Max, Cinema 4D, Blender (via import), and MotionBuilder.
Use FBX when: You are importing motion capture animations into any game engine or professional DCC tool. This is the format you want 90% of the time.
MoCap Online packs include FBX as standard. The FBX animation collection covers all motion categories — locomotion, combat, sports, zombie, and character animations.
BVH (BioVision Hierarchy)
BVH is a simple, text-based format that stores skeletal hierarchy and rotation/position data. It is lightweight, human-readable, and very widely supported — even by older tools that predate FBX. BVH lacks mesh data, material information, and some rigging detail.
Use BVH when: You need to inspect animation data in a text editor, you are working with academic or research tools, or you are using an older pipeline that does not support FBX.
BVH limitations for games: No mesh data, less detailed rigging information, less widely supported in modern game engine import dialogs than FBX. Blender can import BVH; Unreal and Unity both prefer FBX for game development use.
BIP (3ds Max Biped)
BIP is the native animation format for 3ds Max's Character Studio Biped system. It stores animation data specifically for the Biped skeleton rig. If your pipeline is 3ds Max with Biped characters, BIP files load directly without any conversion.
Use BIP when: Your entire pipeline runs in 3ds Max with the Biped rig system. MoCap Online provides BIP format for this workflow.
BIP limitations: Not portable outside 3ds Max. To use BIP animations in Unreal, Unity, or Blender, export from 3ds Max to FBX first.
iClone / BIP for iClone
iClone uses its own animation format for Reallusion's Character Creator pipeline. MoCap Online provides iClone-compatible exports for studios using that toolchain. If you are not in a Reallusion pipeline, you do not need this format.
Which Format Do You Need?
| Your Pipeline | Format to Use |
|---|---|
| Unreal Engine 5 | FBX (UE5-format or standard humanoid) |
| Unity | FBX (with Humanoid rig type in import settings) |
| Blender | FBX |
| Maya | FBX |
| 3ds Max with Biped | BIP |
| MotionBuilder | FBX |
| iClone / Character Creator | iClone format |
| Research or academic tools | BVH |
MoCap Online Format Coverage
Every MoCap Online animation pack includes multiple format options in a single purchase: FBX, Unreal Engine-optimized, Unity, Blender, BIP (3ds Max), and iClone. You buy once and get the format your pipeline needs without conversion overhead.
Browse the full animation library or download a free pack to test all included formats with your own toolchain before purchasing.
FBX File Format: Technical Background
Understanding what the FBX format actually contains — and why it became the universal standard — helps you make better decisions about export settings and troubleshoot import problems.
Developed by Kaydara. FBX was created by the Canadian company Kaydara in the late 1990s as the native file format for their FilmBox motion capture software. Autodesk acquired Kaydara in 2006, bringing FBX into the Autodesk ecosystem (Maya, 3ds Max, MotionBuilder). From there it became the cross-application exchange standard across every major game engine and DCC tool. The "FBX" name predates Autodesk — it stands for FilmBox, not anything Autodesk named it.
FBX binary vs. FBX ASCII. Every FBX file exists in one of two serialization formats. FBX binary is the compact encoding — smaller file sizes, faster to parse, but not human-readable. FBX ASCII is a text-based version of the same data structure — readable in any text editor, useful for debugging, but significantly larger on disk. Both formats contain identical data. Most DCC tools default to FBX binary for production export. If you need to inspect skeleton bone names, hierarchy structure, or track down why an animation is importing incorrectly, exporting as ASCII and searching for bone names in a text editor is the fastest diagnostic approach.
What an FBX file stores. A single FBX file is a container for scene data: the mesh geometry (vertices, normals, UV coordinates), the skeletal hierarchy (named bones and their parent-child relationships), skin binding weights (per-vertex influence values for each bone), material and texture references, animation curves (keyframe data for each bone's translation, rotation, and scale over time), and blend shape or morph target data. For game development workflows, you typically import only the skeleton and animation curves — the mesh is imported separately to avoid duplicating geometry for every animation clip.
Export settings that affect animation quality. The two settings that most frequently cause problems are axis orientation and unit scale. Unreal Engine uses a left-handed, Z-up coordinate system; Maya and Blender default to right-handed systems. The FBX exporter converts between these — but only if the settings match your engine's expectations. Incorrect axis conversion produces characters that arrive rotated 90 degrees or facing backward. Unit scale mismatches produce characters imported at 1% or 100x their intended size. MoCap Online packs include engine-specific format variants with axis and scale settings pre-applied so import works without reconfiguration.
FBX, BVH, and BIP in Practice: Import Pipelines and Compatibility Trade-offs
FBX is the de facto interchange format for game animation because it carries skeleton hierarchy, bind poses, animation curves, and mesh data in a single file, and both Unreal Engine and Unity have mature, well-tested FBX importers that handle the full range of standard humanoid animation content correctly. The practical FBX compatibility pitfall for game developers is the axis convention difference between content creation tools: Maya exports FBX with Y-up orientation, while Blender defaults to Z-up, and 3ds Max exports with Z-up as well. Unreal Engine applies automatic axis conversion on import, but the conversion is applied differently depending on the FBX version and the "Force Front XAxis" import setting. When a locomotion clip imports with the character facing the wrong direction, the root cause is almost always an axis convention mismatch between the exporting tool and the importer's expected orientation — not an error in the animation data itself.
BVH (BioVision Hierarchy) is the original motion capture interchange format and remains widely used for raw capture data from consumer inertial suits, academic databases, and free motion capture repositories. Its limitation for game production is that BVH does not carry mesh data — it is skeleton and animation curves only — and the skeleton hierarchy and joint naming are not standardized across capture systems. Every BVH file from a different capture source may use a different skeleton structure, joint naming convention, and reference pose. This means BVH files almost always require a retargeting pass before they can be applied to a game character, and the retargeting quality depends on how closely the BVH skeleton matches the target rig. For game developers, BVH is most appropriate as a stepping-stone format when working with raw mocap data that will be processed and retargeted — not as the final delivery format.
The BIP format is specific to 3ds Max Biped and carries the full benefit of Biped's native workflow: layers, constraints, and figure mode data are preserved in a way that FBX export cannot replicate. For studios built around a 3ds Max Biped pipeline, BIP files from a professional library like MoCap Online eliminate the export/import round-trip that FBX requires and produce faster iteration cycles when adjusting animations. The BIP workflow limitation is exclusivity — BIP files are only useful if the entire animation pipeline stays within 3ds Max Biped; if the workflow moves to any other tool or engine, the BIP data must be exported to FBX first, at which point the Biped-native layer data is baked out. For cross-tool pipelines, FBX remains the better primary format even when part of the pipeline uses 3ds Max.
Animation Format Conversion: Avoiding Data Loss Between Tools
Converting animation data between formats is where subtle quality loss accumulates. The safest conversion path for game production is the one with the fewest steps: source tool to FBX to game engine, without additional passes. Each additional tool in the chain introduces another opportunity for axis convention mismatches, curve interpolation changes, or constraint data loss. When a conversion is unavoidable, validate the result by comparing a known-correct frame from the source against the same frame in the converted output. This catches axis flips, scale errors, and missing bone data that look correct in isolation but break during the full animation range.
FBX version compatibility is an underappreciated conversion pitfall. FBX files come in different versions (FBX 2013, 2016, 2019, 2020) and the importing engine's SDK version determines which it handles correctly. Problems arise at the edges: a file exported from a very recent version of Maya using the latest FBX SDK may use features not supported by an older engine's importer. If an FBX import produces errors in the engine console, checking the FBX version and downgrading to FBX 2016 resolves most importer compatibility issues without changing any animation data. For more on animation file formats, see our full format guide.