6 Rigid Body Skeleton Markerset

Main PageSkeleton Tracking6 Rigidbody Skeleton Markerset
New in Motive 2.0

Page Scope

This page provides instructions on how to use the 6-Rigid Body skeleton markerset for full-body skeleton tracking.

Warning2.png

The 6 Rigid Body skeleton feature is not exposed in Motive 2.0. To access this skeleton template, please contact our support.


Overview


The 6 Rigidbody Skeleton markerset allows users to use just rigid bodies to establish full body skeleton tracking. A total of six rigid bodies are attached at specific locations of the subject and Motive solves the entire skeleton through inverse kinematics. The rigid bodies are attached to the head, left-hand, right-hand, hip, left-foot, and right-foot, and then the pivot point of those rigid bodies needs be translated over to the corresponding joints.

6RBSkeleton Overview 20.png

Creating 6RB skeleton markerset


Marker Placements

Step 1) Prepare 6 rigid bodies with markers.

Step 2) Attach rigid bodies at the following locations:

  • Head: Place the rigid body back of the head. This can be replaced by an HMD.
  • Hip: Place the rigid body on the back, slightly above the hip bone.
  • Right Hand / Left Hand

Step 3) Make sure the rigid bodies are securely attached.

Creating the Skeleton

Step 1

First of all, define rigid body assets for all of the attached rigid bodies.

Step 2

Name the rigid bodies with the following syntax:

Rigid body names
  • "(Skeleton Name)Head"
  • "(Skeleton Name)Hip"
  • "(Skeleton Name)LHand"
  • "(Skeleton Name)RHand"
  • "(Skeleton Name)LFoot"
  • "(Skeleton Name)RFoot".

Step 3

Attach the rigid bodies to the respective parts of the subject's body.

Step 4

Now you need to position the rigid body pivot points. Use the Gizmo tool and translate the rigid body pivot points so that each pivot point is located at its respective parent joint axis.

Step 5

Orient the rigid body pivot points so that all of its z-axis is facing in forward-direction. This can be done easily using the Rigid Body pane. Ask the subject to face towards the positive-z direction (determined by the global coordinate system) and use the Edit tab on the Rigid Body pane to reset the orientations of the each rigid body. This will align the rigid body orientation with the global coordinate axis, making the z-axis direct forward.

thumb|center|Reseting rigid body orientation

Step 6

The rigid body pivot point should be positioned and oriented something like the image below (Grayscale image).

Step 7

Open the Skeleton pane and select the 6 Rigidbody Skeleton markerset. Name the skeleton that matches the prefix given to the rigid bodies.
6RB CreatedSkeleton.png

Step 8

Select all six rigid bodies and press "Create" on the Skeleton pane.