Articles on: Integrations

Send data to OpenTrack

OpenTrack Setup Guide


This guide explains how to set up OpenTrack to receive head tracking data from Playability.


What is OpenTrack?


OpenTrack is an open-source head tracking application that translates head movements into game inputs. It's commonly used with flight simulators, racing games, and other applications that support head tracking.


Prerequisites


  • Playability installed and running
  • OpenTrack installed (Download from GitHub)
  • A webcam for face detection (required for Playability to track your head)


Step 1: Install OpenTrack


  1. Download the latest OpenTrack release from GitHub
  2. Extract the ZIP file to a folder (e.g., C:\Program Files\opentrack)
  3. Run opentrack.exe to launch OpenTrack


Step 2: Configure OpenTrack Input


OpenTrack needs to be configured to receive UDP data from Playability:


  1. In OpenTrack, click on Input (or press F1)
  2. Select UDP over network from the dropdown
  3. Click Start to begin listening for UDP data
  4. Verify the settings:
  • Protocol: UDP over network
  • Port: 4242 (default)
  • Bind address: 127.0.0.1 (localhost)


Step 3: Configure OpenTrack Output


Configure OpenTrack to send tracking data to your game or application:


  1. In OpenTrack, click on Output (or press F2)
  2. Select your preferred output method:
  • FreeTrack 2.0 Enhanced - For older games
  • vJoy - For games that support vJoy
  • SimConnect - For Microsoft Flight Simulator
  • UDP over network - For applications that accept UDP input
  • Wine - For Linux compatibility
  1. Configure the output settings according to your game's requirements
  2. Click Start to begin output


Step 4: Configure Playability


Enable OpenTrack output in Playability:


  1. Open Playability
  2. Navigate to Connections **in the sidebar then click on **OpenTrack tab
  3. Enable "Enable OpenTrack Output" toggle
  4. (Optional) Enable "Auto-start OpenTrack Output" if you want it to start automatically when Playability launches


What Happens When Enabled


When OpenTrack output is enabled, Playability will:

  • Automatically enable face detection (required for head tracking)
  • Start sending head pose data via UDP to 127.0.0.1:4242
  • Send data at approximately 30fps (whenever new camera data arrives)


Step 5: Verify Connection


To verify that data is flowing correctly:


  1. In OpenTrack: Look at the main window - you should see the head position indicator moving when you move your head
  2. In Playability: Ensure your webcam is active and face detection is running
  3. Test: Move your head slowly and watch the OpenTrack visualization respond


Data Format


Playability sends head tracking data in the following format:


  • Protocol: UDP (User Datagram Protocol)
  • Port: 4242
  • Host: 127.0.0.1 (localhost)
  • Format: Binary (48 bytes)
  • 6 double-precision floats (8 bytes each, little-endian)
  • Order: X, Y, Z, Yaw, Pitch, Roll
  • Translation values (X, Y, Z) are in meters
  • Rotation values (Yaw, Pitch, Roll) are in degrees


Coordinate System


  • X: Left/Right translation (meters)
  • Y: Up/Down translation (meters)
  • Z: Forward/Back translation (meters)
  • Yaw: Rotation around Y-axis (degrees)
  • Pitch: Rotation around X-axis (degrees)
  • Roll: Rotation around Z-axis (degrees)


Troubleshooting


OpenTrack Not Receiving Data


  1. Check OpenTrack is running: Ensure OpenTrack is started and listening on port 4242
  2. Check firewall: Windows Firewall may be blocking UDP port 4242
  • Add an exception for OpenTrack in Windows Firewall
  • Or temporarily disable firewall to test
  1. Check Playability settings: Verify "Enable OpenTrack Output" is toggled on
  2. Check face detection: Ensure your webcam is active and face detection is working
  • Look for the face detection indicator in Playability
  • Make sure you're facing the camera with good lighting


Data Not Smooth


  1. Lighting: Ensure you have good lighting on your face
  2. Camera position: Position your camera so it has a clear view of your face
  3. Calibration: In Playability, you may need to calibrate head tracking for better accuracy


OpenTrack Shows No Movement


  1. Verify input: In OpenTrack, check that the input source shows activity
  2. Check mapping: Ensure OpenTrack's input mapping is correct
  3. Test with another source: Try using OpenTrack's built-in test input to verify output is working


Port Already in Use


If you get an error that port 4242 is already in use:


  1. Check for other instances: Make sure no other application is using port 4242


Advanced Configuration


Adjusting Sensitivity


If head movements are too sensitive or not sensitive enough:


  1. In OpenTrack, use the Mapping tab to adjust sensitivity curves
  2. Adjust the Smoothing settings to reduce jitter
  3. Use Filtering options to fine-tune responsiveness


Coordinate System Adjustments


If the tracking feels inverted or rotated incorrectly:


  1. In OpenTrack, use the Mapping tab
  2. Adjust axis mappings and invert axes as needed
  3. Use the Relative translation option if needed


Additional Resources



Notes


  • Playability sends data continuously while OpenTrack output is enabled
  • The connection is one-way: Playability → OpenTrack
  • No configuration is needed in Playability beyond enabling the toggle
  • Face detection must be enabled for OpenTrack output to work (this happens automatically)


Updated on: 18/12/2025