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MOCAP Tutorials

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🌀 Re-targeting Movements in Blender

Using Motion Capture Data from Perception Neuron 3 (.bvh)

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📌 What is MOCAP and Retargeting?

Motion Capture (MOCAP) is a technique for recording human movement and translating it to a digital character. In this guide, we use .bvh files captured with Perception Neuron 3 (PN3) and apply that movement to a custom 3D model in Blender.

Retargeting refers to the process of mapping motion data from one skeleton (e.g., a BVH armature) onto another (e.g., your character model), allowing different rigs or body types to perform the same animation.

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Index

• Option 1: Manual Retargeting (No Armature on Import)
• Option 2: Retargeting with Auto-Rig Pro – Smart + Remap
• Option 3: Retargeting with Auto-Rig Pro – Existing Rig + Remap

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Option 1: Manual Retargeting (No Armature on Import)

This method works best when you want to manually align BVH motion to a static mesh model without pre-existing rig constraints.

💡 Tips

• Make sure your character is in T-pose or A-pose before rigging
• Avoid scaling bones in Edit Mode — this can break animation playback
• Use orthographic views (Numpad 1/3/7) to check alignment
• You can clean up or simplify keyframes using the Graph Editor

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Step-by-Step Instructions

First, create a new Blender project and save the file as Character-with-MOCAP-1.blend. Then, follow these steps:

1. Import Your Character Mesh

• In Blender, go to File → Import → OBJ/FBX (or whatever format your model is in)
• Make sure your model does not include an armature

2. Import Your BVH File

• Go to File → Import → Motion Capture (.bvh)
• Select your .bvh file
• Before importing: In the Transform panel on the right, set the Scale to 0.1
• Click Import BVH
• This will create a BVH armature with baked motion keyframes

3. Align BVH Scale with Character

• Your mocap character may appear larger/smaller than your mesh
• Use S (scale) on the BVH armature only (Object Mode)
• Do not scale the armature in Edit Mode or using non-uniform transforms

4. Match Bone Positions

• Select the BVH armature
• Enter Edit Mode
• Move and adjust bones so they visually align with your character’s mesh
• Focus on key joints like the shoulders, hips, knees, and feet for accurate alignment

5. Parent the Mesh

• To apply the BVH armature to your mesh, select the mesh first, then Shift+click the armature
• Press Ctrl+P and choose With Automatic Weights
• Note: This works best if your mesh is roughly aligned with the armature
• Tip: Use Weight Paint mode to fine-tune how bones influence the mesh if deformations look incorrect

6. Play the Timeline

• Press Spacebar or drag the timeline to preview the movement
• Your BVH skeleton should animate based on the captured motion

7. Export short video

• Go to the Output Properties tab (printer icon in the Properties Panel).
• Set the frame range to max 1-500.
• Under Output, choose a location to save and set the file format to FFmpeg video.
• In the Encoding section (appears when FFmpeg is selected):
  • Set Container to MPEG-4
  • Set Video Codec to H.264
• Go to Render → Render Animation (Ctrl + F12).
• Once done, your video file will be saved in the selected folder.

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Option 2: Retargeting with Auto-Rig Pro – Smart + Remap

This option uses the Auto-Rig Pro add-on for Blender — a powerful tool designed to simplify rigging, animation retargeting, and character preparation for games or film.

💡 Tips

• Make sure your character is in T-pose or A-pose before rigging
• If joints don’t align properly, you can manually adjust bone mapping in the Remap tab
• Auto-Rig Pro also supports batch retargeting for multiple animations

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Install Auto-Rig Pro

Auto-Rig Pro is a paid Blender add-on that provides tools for:

• Creating advanced rigging systems with controllers and constraints
• Retargeting motion from external sources (like BVH or FBX files)
• Exporting animations to game engines

➡️ Download and install it from your Blender Preferences:

• Edit → Preferences → Add-ons → Install...
• Select the .zip file, install, and enable Auto-Rig Pro: Rig Tools

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Step-by-Step Instructions

First, create a new Blender project and save the file as Character-with-MOCAP-2.blend. Then, follow these steps:

1. Import Your Character Mesh
   • In Blender, go to File → Import → OBJ/FBX (or whatever format your model is in)
   • Make sure your model does not include an armature
2. Watch the video tutorial
   • 🎥 Follow only the first 10 minutes of the linked tutorial video to complete the steps below.
   • The rest of the video covers advanced features that are not required for this exercise.
3. Play the Timeline
   • Press Spacebar or scrub through the timeline to preview the animation on your character
4. Export a Short Video
   • Use Render → Render Animation to export a short .mp4 showcasing the result

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Overview of the process

Create a Rig with Auto-Rig Pro: Smart

• Select your character mesh
• Open the Auto-Rig Pro → Smart panel (found in the N sidebar under the Auto-Rig tab)
• Place the rig markers following your character’s anatomy (chin, shoulders, hips, knees, etc.)
• Click Go! to generate a full Auto-Rig Pro armature

🛠️ You can tweak the rig to better fit your model after generation.

Retarget Using Auto-Rig Pro: Remap

• Go to Auto-Rig Pro → Remap
• Set:
  • Source Armature → your imported BVH armature
  • Target Armature → your newly created Auto-Rig Pro rig

Then configure the following:

• Enable Auto-Scale to match proportions
• Check Retarget Actions to transfer animation
• Set Root Bone to the hip of the source rig (usually hip or Hips)

Click Remap to complete the transfer.

Preview & Adjust

Play the timeline to see your character animated with the mocap data

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Tutorial

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Option 3: Retargeting with Auto-Rig Pro – Existing Rig + Remap

This method is ideal if your character already comes fully rigged with Auto-Rig Pro, such as a model you purchased or prepared earlier. Instead of creating a new rig from scratch, you simply retarget motion capture data onto the existing rig using Auto-Rig Pro’s Remap tool.

This is the fastest workflow if:

• Your model already has a working Auto-Rig Pro rig
• You want to test BVH motion on multiple characters quickly
• You’re only interested in applying and previewing motion data

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Step-by-Step Instructions

First, create a new Blender project and save the file as:
Character-with-MOCAP-3.blend

Then, follow these steps:

1. Import Your Character Mesh
   • Go to File → Import → FBX or open a Blender file that includes your Auto-Rig Pro rigged character
2. Import the BVH File
   • Go to File → Import → Motion Capture (.bvh)
   • Set scale to 0.1 in the Transform panel before importing
3. Use Auto-Rig Pro → Remap
   • Open the Remap panel from the Auto-Rig Pro tab
   • Set the BVH Armature as the source
   • Set your existing Auto-Rig Pro rig as the target
   • Enable Auto-Scale, Retarget Actions, and set the hip bone as Root
   • Click Remap

⚠️ Warning: Before retargeting, make sure your existing character rig has:

• Bone names that match the BVH armature (e.g., hip, spine, left_arm)
• Adjusted bone positions that align with the BVH motion structure

If needed, enter Edit Mode on the target armature to rename or reposition bones.

💡 Tips

• If animations look off, check the bone mapping or realign your source and target rigs

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1. Play the Timeline
   • Press Spacebar or scrub through the timeline to preview the animation on your character
2. Export a Short Video
   • Use Render → Render Animation to export a short .mp4 showcasing the result

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Tutorial

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