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OpenTrack

OpenTrack is a head-tracking application for Linux, Windows, and macOS that translates head movements into X-Plane camera movements. Combined with the HeadTrack plugin by amyinorbit, it provides the recommended head-tracking stack for X-Plane 12 on Linux.

Background

  • Developer: Stanisław Halik and contributors
  • Repository: github.com/opentrack/opentrack (ISC license)
  • Platforms: Windows, Linux (macOS currently unmaintained)
  • Compatibility: X-Plane 10, 11, 12

OpenTrack is actively maintained and serves as the successor to FaceTrackNoIR. It supports a wide range of input trackers and output protocols. On Linux, the NeuralNet Tracker provides AI-based head tracking via a standard webcam — no special hardware required.

HeadTrack Plugin

HeadTrack is a lightweight X-Plane plugin that receives 6DOF tracking data over UDP port 4242. It acts as the bridge between OpenTrack and X-Plane — the recommended connection method on Linux, where the built-in OpenTrack X-Plane plugin has known reliability issues.

Features

  • 6DOF head tracking: Pitch, yaw, roll, and X/Y/Z translation
  • NeuralNet Tracker: AI-based face tracking via webcam — no IR hardware needed, runs on CPU (requires ONNX Runtime, see installation)
  • PointTracker: Classical tracking with 3 IR LEDs or reflective points and an IR camera
  • ArUco marker: Printed paper marker in front of a webcam — zero-cost alternative to IR hardware
  • SmoothTrack input: Receives tracking data from the SmoothTrack smartphone app (paid, iOS/Android) via WiFi/UDP
  • Filters and curves: Accela filter, response curves, dead zones, and smoothing per axis
  • Hotkeys: Start/stop, recenter, and zero via keyboard or joystick buttons

Value in Flight Simulation

Head tracking on Windows typically relies on TrackIR with proprietary drivers. On Linux, OpenTrack provides an open-source alternative with native support for webcam-based AI tracking — the NeuralNet Tracker runs without any special hardware, making it the most accessible head-tracking solution for Linux flight simmers. The HeadTrack plugin ensures reliable data delivery to X-Plane 12 where the built-in OpenTrack plugin falls short.

The recommended data flow on Linux:

Input (choose one):
  ├─ NeuralNet Tracker (webcam, no hardware)
  ├─ PointTracker (IR LEDs + camera)
  └─ SmoothTrack (smartphone app)
        │
        ▼
OpenTrack (Linux, built from source or package)
  ├─ Filter: Accela (default, recommended)
  ├─ Response curves per axis
  └─ Output: "UDP over network" → 127.0.0.1:4242
        │
        ▼
HeadTrack plugin (amyinorbit) in X-Plane
  └─ In-sim GUI for sensitivity and smoothing

Avoid the built-in OpenTrack X-Plane plugin

OpenTrack ships its own X-Plane plugin (shared memory based). Under X-Plane 12 on Linux, this plugin has reported reliability issues — freezing or failing to transmit data. Use the HeadTrack plugin with UDP output instead.

Installation

OpenTrack on Debian/Ubuntu

sudo apt install build-essential cmake git libopencv-dev libproc2-dev qt6-base-private-dev qt6-tools-dev
git clone https://github.com/opentrack/opentrack.git
cd opentrack && cmake -B build && cmake --build build --parallel $(nproc)

NeuralNet Tracker requires ONNX Runtime

The build commands above produce a working OpenTrack but without the NeuralNet tracker unless ONNX Runtime is installed. On Debian/Ubuntu, install libonnxruntime-dev if available, or download the ONNX Runtime release and add -DONNXRuntime_DIR=<path> to the CMake command.

HeadTrack Plugin

Download: HeadTrack Releases

Extract the ZIP file to Resources/plugins/. This creates the htrack/ folder with the Linux binary at lin_x64/htrack.xpl.

No additional system packages are required.

Configuration

OpenTrack Output

  1. Launch OpenTrack
  2. Select a tracker as input (e.g., "NeuralNet tracker" for webcam)
  3. Set Output to "UDP over network"
  4. In the output settings, set the target IP to 127.0.0.1 and port to 4242
  5. Configure the Accela filter (default settings work well as a starting point)
  6. Adjust response curves per axis — reduce sensitivity for yaw/pitch to avoid jerky movements

HeadTrack Plugin in X-Plane

After installing the plugin and starting X-Plane:

  1. Open the HeadTrack settings via the plugin menu
  2. Adjust sensitivity and smoothing — start with low values and increase gradually
  3. Use the recenter hotkey in OpenTrack to reset the neutral head position before each flight

NeuralNet Tracker

The NeuralNet Tracker uses a neural network model (ONNX Runtime) to detect face position from a standard webcam. ONNX Runtime must be installed separately before building — on Debian/Ubuntu, install libonnxruntime-dev if available, or download the ONNX Runtime release and set -DONNXRuntime_DIR=<path> during the CMake step. It runs entirely on CPU and does not require a GPU.

  • Works with most USB and built-in webcams
  • Adequate lighting is important — avoid strong backlight
  • Performance: typical CPU usage is low enough to run alongside X-Plane without impact

SmoothTrack (Smartphone)

SmoothTrack is a paid smartphone app (iOS/Android) that provides head tracking via the front camera and sends data over WiFi.

  • In OpenTrack: Set input to "UDP over network" to receive SmoothTrack data
  • Alternatively: Send SmoothTrack directly to HeadTrack on port 4242, bypassing OpenTrack entirely

Sources