How to set up body motion for your avatar, which can be driven by ARKit or Webcam tracking.

kemorig comes with tools to extrapolate the rotation down the character’s torso for a natural look.


Model Requirements

There are no specific requirements for your model or skeleton, other than to have a skeleton with a suitable number of bones to manipulate.

Add the Kemorig Tracking Node to your Anim Blueprint

Open your character’s animation blueprint, and navigate to the AnimGraph.

Right-click the graph and add these nodes:

  • Kemorig Tracking - kemorig helper node for applying tracked motion to your skeleton.
  • Get Final Pose Info - kemorig function for getting pose info for the current frame.

Connect the Kemorig Tracking node in your graph, and pass the output of Get Final Pose Info into it.

Where you place this node in your graph matters! The flow from left to right shows how the pose is built step-by-step. The ARKit Tracking node is additive, meaning whatever pose goes into it will have the ARKit motion added on top of it.

Enter Bone Information

Select the Kemorig Tracking node, and look at the Details panel.

The Category we care about is Tracking Settings.

Check the boxes for the type of motion you want to support:

  • Head Motion support
  • Torso Motion support
  • Arms Counter Rotation support
  • Eye Rotation support

When you check one of these boxes, additional parameters will appear prompting you to enter bone names.

In the dropdowns, select the bone in your character’s skeleton corresponding to the expected body part.

Go through all the fields in Tracking Settings and fill them out with your model’s information. The bones you can enter are:

Head Motion

  • Head
  • Neck

Torso Motion

  • Spine Upper
  • Spine Mid
  • Spine Low
  • Hip Bone Ref (for positional motion)

Arms Counter Rotation

  • Arm L (if using Arms Counter Rotation)
  • Arm R

Eye Rotation

  • Eye L
  • Eye R

Your model’s skeleton may not be a 1-to-1 match for these expected bones. If you skeleton has fewer bones, you can leave any of these fields blank and the rest will work. If your skeleton has more bones (e.g. more than 3 spine bones), you can skip some in the middle when you fill out Upper, Mid, and Low.

Manual Bone Orientations

kemorig automatically calculates the orientation of the bones in this animation node.

However, if you run into tracking issues, you may want to manually input the orientations of each bone.

In the Bone Orientations Category, you can do enter these.

What are Roll, Pitch, and Yaw?

Roll - “tilting”

Pitch - “looking up and down”

Yaw - “looking left and right”