Store Kinect’s v2.0 Motion to BVH File

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The code you used for Kinect 1.0 to obtain a BVH file use the joints information to build bone vectors by reading the Skeleton.

public static double[] getBoneVectorOutofJointPosition(BVHBone bvhBone, Skeleton skel)
{
    double[] boneVector = new double[3] { 0, 0, 0 };
    double[] boneVectorParent = new double[3] { 0, 0, 0 };
    string boneName = bvhBone.Name;

    JointType Joint;
    if (bvhBone.Root == true)
    {
        boneVector = new double[3] { 0, 0, 0 };
    }
    else
    {
        if (bvhBone.IsKinectJoint == true)
        {
            Joint = KinectSkeletonBVH.String2JointType(boneName);

            boneVector[0] = skel.Joints[Joint].Position.X;
            boneVector[1] = skel.Joints[Joint].Position.Y;
            boneVector[2] = skel.Joints[Joint].Position.Z;
..

Source: Nguyên Lê Đặng – Kinect2BVH.V2

Except in Kinect 2.0, Skeleton class has been replaced by the Body class, so you need to change it to deal with a Body instead, and obtain the joints by following the steps quoted below.

// Kinect namespace
using Microsoft.Kinect;

// ...

// Kinect sensor and Kinect stream reader objects
KinectSensor _sensor;
MultiSourceFrameReader _reader;
IList<Body> _bodies;

// Kinect sensor initialization
_sensor = KinectSensor.GetDefault();

if (_sensor != null)
{
    _sensor.Open();
}

We also added a list of bodies, where all of the body/skeleton related
data will be saved. If you have developed for Kinect version 1, you
notice that the Skeleton class has been replaced by the Body class.
Remember the MultiSourceFrameReader? This class gives us access on
every stream, including the body stream! We simply need to let the
sensor know that we need body tracking functionality by adding an
additional parameter when initializing the reader:

_reader = _sensor.OpenMultiSourceFrameReader(FrameSourceTypes.Color |
                                             FrameSourceTypes.Depth |
                                             FrameSourceTypes.Infrared |
                                             FrameSourceTypes.Body);

_reader.MultiSourceFrameArrived += Reader_MultiSourceFrameArrived;

The Reader_MultiSourceFrameArrived method will be called whenever a
new frame is available. Let’s specify what will happen in terms of the
body data:

  1. Get a reference to the body frame
  2. Check whether the body frame is null – this is crucial
  3. Initialize the _bodies list
  4. Call the GetAndRefreshBodyData method, so as to copy the body data into the list
  5. Loop through the list of bodies and do awesome stuff!

Always remember to check for null values. Kinect provides you with
approximately 30 frames per second – anything could be null or
missing! Here is the code so far:

void Reader_MultiSourceFrameArrived(object sender,
            MultiSourceFrameArrivedEventArgs e)
{
    var reference = e.FrameReference.AcquireFrame();

    // Color
    // ...

    // Depth
    // ...

    // Infrared
    // ...

    // Body
    using (var frame = reference.BodyFrameReference.AcquireFrame())
    {
        if (frame != null)
        {
            _bodies = new Body[frame.BodyFrameSource.BodyCount];

            frame.GetAndRefreshBodyData(_bodies);

            foreach (var body in _bodies)
            {
                if (body != null)
                {
                    // Do something with the body...
                }
            }
        }
    }
}

This is it! We now have access to the bodies Kinect identifies. Next
step is to display the skeleton information on-screen. Each body
consists of 25 joints. The sensor provides us with the position (X, Y,
Z) and the rotation information for each one of them. Moreover, Kinect
lets us know whether the joints are tracked, hypothsized or not
tracked. It’s a good practice to check whether a body is tracked
before performing any critical functions.

The following code illustrates how we can access the different body
joints:

if (body != null)
{
    if (body.IsTracked)
    {
        Joint head = body.Joints[JointType.Head];

        float x = head.Position.X;
        float y = head.Position.Y;
        float z = head.Position.Z;

        // Draw the joints...
    }
}

Source: Vangos Pterneas Blog – KINECT FOR WINDOWS VERSION 2: BODY TRACKING

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