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Send Head Tracking Data to OpenTrack

PlayAbility sends six-degree-of-freedom head-pose data to OpenTrack over local UDP. OpenTrack can then filter, map, and expose that data through a protocol supported by the target game.

What you need

A webcam that PlayAbility can use for face detection.
OpenTrack installed on the same Windows computer as PlayAbility.
A game or application with an OpenTrack-compatible output method.

Download OpenTrack from the official OpenTrack releases.

Configure OpenTrack

Open OpenTrack.
Select UDP over network as the tracking input.
Open the input settings.
Set the listening port to 4242.
If an address or interface option is shown, use 127.0.0.1 or localhost.
Select the output protocol required by the target game.
Optionally select an OpenTrack filter and configure its mapping curves.
Select Start in OpenTrack.

The correct OpenTrack output protocol is game-specific. Use the game's or OpenTrack's current documentation rather than assuming that one protocol works with every title.

Enable OpenTrack output in PlayAbility

Open Connections in PlayAbility.
Select OpenTrack.
Turn on Enable OpenTrack Output.
Turn on Main Output.
Optionally turn on Auto-start OpenTrack Output if PlayAbility should enable this output at launch.
Face the selected webcam and allow face detection to start.

Enabling OpenTrack output also enables the PlayAbility face-detection components needed to produce head-pose data.

Auto-start does not launch OpenTrack. It only enables PlayAbility's OpenTrack output when PlayAbility starts. OpenTrack must still be running and listening.

Verify the connection

Confirm that OpenTrack is running with UDP over network selected as its input.
Confirm that PlayAbility's Main Output and Enable OpenTrack Output are on.
Move your head slowly left and right.
Watch the pose values or model in OpenTrack.
Start the target game and confirm that its view responds.

If OpenTrack moves but the game does not, PlayAbility's connection is working. Check the OpenTrack output protocol and the game's head-tracking configuration.

Troubleshooting

OpenTrack shows no movement

Confirm that its UDP input listens on port 4242.
Turn on Main Output and Enable OpenTrack Output in PlayAbility.
Open Settings → General → Webcam and confirm that the intended camera is selected.
Make sure PlayAbility can see a well-lit, unobstructed face.
Stop other software that may already be listening on UDP port 4242.
Restart OpenTrack, then toggle PlayAbility's OpenTrack output off and on.

Movement is inverted or uses the wrong range

Use OpenTrack's mapping and axis-inversion controls. PlayAbility supplies the pose; OpenTrack controls the curves and final transformation sent to the game.

Movement is noisy or delayed

Improve lighting and keep the full face visible.
Reposition the webcam close to eye level.
Reduce heavy webcam filters or effects.
Select and tune an OpenTrack filter.
Check PlayAbility and OpenTrack CPU usage.

OpenTrack moves, but the game does not

Select an OpenTrack output protocol supported by that game.
Confirm that tracking is started in OpenTrack.
Check whether the game requires a launch order, plugin, or in-game head-tracking option.
Follow the game's current documentation for third-party head tracking.

Connection details and limitations

Destination: 127.0.0.1
UDP port: 4242
Direction: PlayAbility to OpenTrack only
Packet: 48 bytes containing six little-endian double-precision values
Value order: X, Y, Z, yaw, pitch, roll

The destination is fixed to localhost, so this integration cannot send directly to OpenTrack on another computer.

Updated on: 30/07/2026

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