Motion Capture File Formats Explained: FBX, BIP, Unreal, Unity, and Blender
Introduction
Motion capture animation is delivered in a lot of different file formats, and picking the wrong one can cost you hours of cleanup work. This guide explains what each format is, where it came from, what it's good at, and when you should actually use it.
This is written for game developers, animators, and technical artists who want clear answers about format choice without wading through documentation.
Quick Reference
| Format | Type | Best For |
|---|---|---|
| FBX | Universal interchange | Any engine, any tool, safest default |
| BIP | 3ds Max Biped animation | 3ds Max pipelines using Biped rig |
| Unreal Engine native | UE skeletal mesh animation | Direct Unreal workflows, Epic Skeleton |
| Unity native | Unity Humanoid / Mecanim | Direct Unity workflows |
| Blender native | Blender-rigged FBX | Blender animators and game dev |
| iClone | Reallusion iClone format | iClone / Character Creator workflows |
| BVH | Raw mocap data | Research, inertial suit exports, legacy |
| USD | Emerging universal format | Pixar-influenced film pipelines |
| glTF | Web / real-time | WebGL, AR/VR, lightweight delivery |
FBX (Filmbox)
Developer: Autodesk (originally Kaydara, acquired 2006)
Extension: .fbx
Type: Binary or ASCII interchange format
What it is
FBX is the universal interchange format for 3D content. It was designed to move models, rigs, animations, cameras, lights, and materials between different 3D applications and game engines without losing data. Virtually every 3D tool you will ever use supports FBX import and export.
What it stores
- Mesh geometry and UVs
- Bone hierarchies and skinning weights
- Animation curves (rotation, translation, scale over time)
- Cameras, lights, and materials
- Optional blend shapes / morph targets
- Multiple animation takes in a single file
Why it's the default
FBX is the safest choice for mocap delivery because nearly every tool can read it. If you're unsure what format to use, use FBX.
Where it falls short
- Binary FBX versions are not backward compatible across major releases — an FBX exported from 2024 Autodesk tools may not import cleanly into 2018 tools
- Large mesh-plus-animation files can become unwieldy
- Some engine-specific features (UE5 IK bones, UE-specific curves, Unity Humanoid retargeting) require additional setup on top of the base FBX
When MoCap Online uses FBX
Every MoCap Online animation pack ships with an FBX version for universal compatibility. It's the format to grab when you're working in a tool we don't have a native version for, or when you want the most flexibility.
BIP (3ds Max Biped)
Developer: Autodesk (3ds Max Character Studio)
Extension: .bip
Type: Binary animation format for 3ds Max Biped rig
What it is
BIP is the native animation format for the Biped character rigging system in Autodesk 3ds Max. Biped has been part of 3ds Max since the 1990s as Character Studio, and it's still used in many established game development pipelines. A BIP file contains animation data specifically for a Biped rig — keyframes, footstep markers, and the Biped's layer system data.
What it stores
- Biped rig animation keys (body, limbs, tail, ponytail chains)
- Footstep data and foot planting information
- Layer information for animation editing
- In-place vs. root motion variants
Why it's still relevant
Many game studios built their pipelines on 3ds Max Biped years ago, and those pipelines still work. BIP files open instantly in Max, work directly with Biped-rigged characters, and don't require any conversion. For established Max pipelines, BIP is faster to work with than FBX.
Where it falls short
- Only usable inside 3ds Max with a Biped rig
- Cannot be opened directly in Maya, Blender, Unreal, Unity, or any other tool
- Tied to Autodesk's Biped implementation — custom rigs need bone mapping
When MoCap Online uses BIP
Every MoCap Online animation pack ships with a BIP version alongside FBX for studios using 3ds Max Biped. If you're working in Max, BIP is the fastest way to load animations onto a Biped character.
Unreal Engine Native Format
Developer: Epic Games
Extension: Unreal .uasset files (wrapping the animation)
Type: Unreal Engine Animation Sequence asset
What it is
"Native Unreal format" isn't a file extension — it's an animation pack that has been imported into Unreal Engine, applied to the Epic Skeleton, saved as .uasset files, and packaged as a plugin or content folder that drops directly into your Unreal project.
What it stores
- Animation sequences ready for Unreal's Animation Blueprint system
- Already on the Epic Skeleton (UE4 or UE5)
- Root motion variants where applicable
- Notifies, curves, and metadata for use in state machines and blend spaces
Why it matters
When an animation pack ships in native Unreal format, you skip the entire import/retarget workflow. The animations drop into your project already on the Epic Skeleton, already compatible with your character, already set up for the Animation Blueprint.
Where it falls short
- Tied to the Unreal Engine version used to package it — major version differences may require re-import
- Not usable outside Unreal without re-exporting
When MoCap Online uses Unreal native
Every MoCap Online pack ships with an Unreal Engine version set up on the Epic Skeleton. This is the fastest way to get animations into an Unreal project — copy the folder into Content/, and the animations are ready to wire into your character's Animation Blueprint.
Unity Native Format
Developer: Unity Technologies
Extension: .unitypackage or folder with .fbx + .meta files
Type: Unity Mecanim-ready asset package
What it is
A Unity native mocap pack is a .unitypackage or folder of files already configured for Unity's Mecanim animation system. The FBX files inside have their import settings pre-configured for the Humanoid rig type, and the pack typically includes demo Animator Controllers showing how to wire up the animations.
What it stores
- Humanoid-configured FBX animation files
- Avatar definitions ready for retargeting
- Optional demo Animator Controllers
- Optional sample scenes showing the animations in action
Why it matters
Unity's Humanoid system allows any Humanoid-configured animation to play on any Humanoid character with no manual retargeting. When an animation pack ships in Unity native format, the Humanoid configuration is already done — you just drop the pack into your project and reference the animations from your existing Animator Controllers.
Where it falls short
- Humanoid is great for human characters but doesn't work for creatures, vehicles, or non-biped characters
- Unity import settings can break between major Unity versions
When MoCap Online uses Unity native
Every MoCap Online pack ships with a Unity version configured for Humanoid. Drop the .unitypackage into your Unity project, the animations appear in your asset list ready to use with any Humanoid character.
Blender Native Format
Developer: Community / Blender Foundation
Extension: .blend file or rigged FBX import
Type: Blender scene with character rig and animation
What it is
Blender native mocap usually means a .blend file containing a rigged character with the animations pre-applied, or an FBX file designed to import cleanly into Blender with its rig and animation intact. Blender has become a serious game development animation tool over the last few years, and mocap packs designed for Blender workflows save significant setup time.
What it stores
- Rigged character ready for Blender's armature system
- Animation data in Blender's action system
- NLA tracks if multiple animations are packaged together
- Optional Rigify compatibility for retargeting
Why it matters
Blender's rig and armature system is different from 3ds Max, Maya, and Unity, so FBX files not designed for Blender often import with rig issues. A pack designed specifically for Blender solves these issues upfront.
Where it falls short
- Blender versions change significantly between releases — files from older versions may need re-import
- Rig compatibility with Rigify and other popular rigs requires per-project setup
When MoCap Online uses Blender native
MoCap Online Blender packs include rigged characters and FBX files configured for clean Blender import. Use these when your animation pipeline is Blender-first.
iClone Format
Developer: Reallusion Extension: iClone project files Type: Reallusion iClone character animation
What it is
iClone is Reallusion's character animation and virtual production tool, and it has its own native character rig and animation format. iClone integrates with Character Creator for character generation and with Unreal Engine for final rendering.
Why it matters
For content creators, cinematic animators, and virtual production workflows using iClone and Character Creator, a native iClone format saves significant setup time versus retargeting FBX files.
When MoCap Online uses iClone
MoCap Online ships iClone versions of animation packs for creators using the Reallusion workflow. Drop the pack into iClone and the animations are ready to use on Character Creator characters.
BVH (Biovision Hierarchy)
Developer: Biovision (now defunct)
Extension: .bvh
Type: Text-based skeleton and animation format
What it is
BVH is an older text-based motion capture format that stores a skeleton hierarchy and animation data. It dates back to the 1990s and is still the standard raw output format for inertial mocap suits and for motion capture research.
Why it's still used
- Human-readable text format makes it easy to inspect and debug
- Widely supported by mocap research and analysis tools
- Default output from many inertial mocap suits
Where it falls short
- Skeleton definition is embedded in every file — each BVH is a self-contained skeleton
- No standard for bone naming or orientation conventions
- Typically requires retargeting before use in a game engine
- No mesh, material, or multi-take support
When BVH shows up in mocap workflows
You'll encounter BVH primarily when working with raw mocap from inertial suits (Rokoko, Xsens) or with research datasets. Most commercial animation libraries ship FBX or engine-native formats instead of BVH because of the retargeting overhead.
USD (Universal Scene Description)
Developer: Pixar (open source)
Extension: .usd, .usda, .usdc, .usdz
Type: Universal 3D scene and animation interchange
What it is
USD is Pixar's open-source scene description format, originally developed for film production pipelines and now increasingly adopted in games and VFX. USD can represent geometry, materials, animation, lighting, and scene composition in a single file or layered across multiple files.
Why it matters
USD is the future of large-scale 3D pipelines. Apple's ARKit, NVIDIA Omniverse, Unreal Engine, and Maya all have strong USD support now. For pure mocap delivery it's not yet the standard, but it's growing.
Where it stands today
USD is still emerging in game development. FBX remains the more practical choice for mocap delivery in 2026, but expect USD adoption to grow.
glTF
Developer: Khronos Group
Extension: .gltf, .glb
Type: Efficient 3D delivery format for web, AR, and real-time
What it is
glTF is an open standard for delivering 3D content to real-time applications, especially web and AR/VR. It's lightweight, efficient, and well-supported by modern 3D web frameworks (Three.js, Babylon.js, model-viewer).
Why it matters for mocap
For delivering animated characters to web or AR projects, glTF is significantly more efficient than FBX. It's the preferred format for WebGL character animation and for mobile AR experiences.
Where it falls short
- Less complete for complex production pipelines than FBX
- Tooling is still catching up for heavy animation workflows
How to Choose the Right Format
The right format depends almost entirely on where the animation is going:
- Going to Unreal Engine? Native Unreal format first, FBX as fallback
-
Going to Unity? Native Unity format (
.unitypackagewith Humanoid) first, FBX as fallback - Going to Blender? Native Blender pack first, FBX as fallback with manual rig setup
- Going to 3ds Max with Biped? BIP file, fastest workflow
- Going to iClone / Character Creator? Native iClone format
- Going to a web or AR project? glTF
- Going to multiple engines or uncertain? FBX — it's the safest fallback everywhere
MoCap Online ships every animation pack in FBX, BIP, native Unreal, native Unity, Blender, and iClone, so you can pick the format that matches your workflow without any conversion.
Frequently Asked Questions
What is the best file format for motion capture?
FBX is the best universal format for motion capture because nearly every 3D application and game engine supports it. For specific workflows, engine-native formats (Unreal, Unity, Blender, 3ds Max Biped) are faster to work with because they skip the import and retarget step.
What is the difference between FBX and BIP?
FBX is a universal 3D interchange format supported by virtually every 3D tool, while BIP is a proprietary format for the 3ds Max Biped character rigging system. FBX is more portable; BIP is faster inside 3ds Max workflows that use Biped rigs.
Can I use FBX animations in Unreal Engine?
Yes, Unreal Engine imports FBX animations via its standard import pipeline. However, if the FBX is not targeted at the Epic Skeleton, you may need to retarget the animation using the Unreal IK Retargeter. MoCap Online ships native Unreal Engine versions of its packs on the Epic Skeleton to skip this step.
What format does Unity use for motion capture?
Unity imports FBX animations and configures them using its Humanoid or Generic rig types in Mecanim. For Humanoid characters, an FBX configured as Humanoid can be played on any other Humanoid character. MoCap Online ships native Unity versions of its packs pre-configured as Humanoid.
Can I use Mixamo FBX animations with MoCap Online packs?
Yes, both use FBX as the delivery format. However, Mixamo uses its own skeleton, so using Mixamo animations alongside MoCap Online animations on the same character requires retargeting one of them to match. MoCap Online packs ship on the Epic Skeleton (Unreal) or Unity Humanoid, which are more standard.
What is BVH format used for?
BVH (Biovision Hierarchy) is a text-based motion capture format that dates to the 1990s. It's still used as the raw output format for inertial mocap suits (like Rokoko Smartsuit) and for research datasets. Most commercial animation libraries ship FBX or engine-native formats instead of BVH because BVH typically requires retargeting before use in a game engine.
What is the difference between in-place and root motion FBX?
An in-place FBX has the animation playing at the origin without moving the character through the world — movement is handled by gameplay code. A root motion FBX has the character's world position driven by the animation itself, so the root bone moves through the scene. Many commercial packs ship both variants.
Does MoCap Online support all the major file formats?
MoCap Online ships every animation pack in FBX, BIP, native Unreal Engine, native Unity, Blender, and iClone formats. This covers the major game development and animation pipelines without requiring conversion or retargeting.
Related Resources
- MoCap Online vs Mixamo — professional studio capture compared to free auto-generated animations
- MoCap Online vs Rokoko — optical capture compared to DIY inertial motion capture suits
- MoCap Online vs Plask — studio mocap compared to AI video-to-animation tools
- Motion Capture Glossary — 20 essential motion capture terms defined
- Motion Capture Industry Statistics 2026 — market size, growth projections, and trends
- Complete Guide to Motion Capture for Indie Developers — how to choose and use mocap data
- Free Animation Packs — try professional Vicon-captured animations at no cost
- Browse All Animation Packs — 42 curated packs for every use case
Last updated: April 2026 | Reviewed quarterly for accuracy
