Export body animations from the control rig to FBX files compatible with Unreal Engine.

Overview

The Export Body Animation operator bakes the control rig's visual transforms and writes them to a binary FBX file. The export handles axis conversion and scaling automatically so the resulting file imports correctly into Unreal Engine.

How to Export

1. Select the rig instance in the sidebar panel
2. Make sure the instance has a body_rig (the MetaHuman body skeleton)
3. Open the Animation sub-panel
4. Click Export in the Body FK Animation section
5. Choose a file path and name (default: {instance_name}_body.fbx)
6. Set the Bake Step if desired (default: 1)
7. Confirm the export

Export Settings

Bake Step

• Step 1 — Bake every frame (highest quality, largest file)
• Step 2 — Bake every other frame
• Step 10 — Bake every 10^th frame (fastest export, lower quality)

Higher step values skip frames during the visual bake pass. Intermediate frames are interpolated during playback. Use step 1 for final exports and higher values for previews.

Frame Range

The export uses the scene's playback range:

• Start frame: context.scene.frame_start
• End frame: context.scene.frame_end

Set your scene's frame range before exporting to control which frames are included.

What Happens During Export

1. Document creation — Creates a new FBX document with:

   • Right-hand coordinate system, Z-up axis (matches Unreal Engine)
   • Scene frame rate from Blender

2. Rest data collection — Reads the body rig's bone rest transforms:

   • Parent-relative positions, rotations (quaternion WXYZ), and scales
   • Full bone hierarchy preserved

3. Visual animation bake — Samples the rig pose at each frame (respecting bake_step):

   • Evaluates pose_bone.matrix (post-constraint visual transform)
   • Converts to parent-relative local space
   • Extracts location, quaternion rotation, and scale

4. Skeleton hierarchy — Builds the FBX node hierarchy matching the bone parent-child structure with a scale factor of 100.0 (Blender meters → Unreal centimeters)

5. Animation curves — Writes per-bone animation data:

   • Quaternion rotation converted to Euler XYZ (degrees)
   • Location scaled by 100.0
   • One FBX animation take named "Unreal Take"

6. Binary FBX write — Encodes and writes the file in FBX binary format

Unreal Engine Import

The exported FBX is configured for direct import into Unreal Engine:

In Unreal Engine's FBX import dialog:

• Set the skeleton asset to your MetaHuman's skeleton
• Animation should import with correct bone transforms and timing