vrcft-steam-frame

Eye tracking for the Steam Frame in VRChat through VRCFaceTracking (VRCFT): a VRCFT module, a guided calibration/tuning tool, and setup scripts.

Unofficial. It reads a private, undocumented shared-memory format on the headset, which can change with any Frame update. Use at your own risk.

What you get

	Steam Link OSC only	+ frameeyeosc (this repo's preferred path)
Gaze	yes (both eyes mirrored)	yes, per eye
Blink	heuristic (both eyes together)	real eyelid openness
Wink	no	partly (the tracker couples the eyes, see below)
Mouth / face	no (the Frame has no lower-face cameras)	no

The Steam Link driver's OSC eyelid value (/tracking/eye/EyesClosedAmount) is always 0 on the Frame and its left/right values are identical. Real per-eye eyelid openness only exists in the headset's shared memory (/dev/shm/eye-server.mmap), which frameeyeosc reads and sends over OSC.

How it fits together

Steam Frame (SteamOS, aarch64)                     PC (Windows)
  eyetracking service -> /dev/shm/eye-server.mmap
        |                                            VRCFaceTracking
  frameeyeosc  ---- OSC/UDP :9020 (LAN) --------->   SteamFrameVRCFTModule  --> VRChat (OSC :9000)
                                                          ^
  Steam Link driver ---- OSC/UDP :9015 (loopback) ---------+   (fallback when frameeyeosc is not running)

Requirements

Tested with: Windows 11, VRCFaceTracking 5.4.5 (Steam version), Steam Frame on SteamOS build 20260922 (shared-memory ABI version 4), VRChat with a VRCFT unified-expressions avatar (FT/v2/* parameters).

• .NET 10 SDK on the PC (winget install Microsoft.DotNet.SDK.10, or dotnet-install.ps1 -Channel 10.0 for a per-user install)
• SSH access to the headset (or a terminal on it) to build frameeyeosc
• The VRCFT SteamLink module must be uninstalled/disabled: both listen on UDP 9015 and only one may run

Setup

1. SteamVR settings (Steam\config\steamvr.vrsettings, close SteamVR first), under driver_vrlink: "OSCOutPort": 9015 and "shareEyeTrackingData": true (in the UI: Advanced settings, Video, Steam Link).
2. Install the module on the PC: powershell -ExecutionPolicy Bypass -File scripts\deploy-module.ps1. It builds, installs into %APPDATA%\VRCFaceTracking\CustomLibs\<guid> and relaunches VRCFT. Always start VRCFT through Steam (steam://rungameid/3329480): starting the exe directly never spawns the module process.
3. Build frameeyeosc on the headset: copy scripts/headset-setup.sh over and run it (installs Rust under ~/.cargo, nothing else).
4. Start it: scripts/headset-run.sh <PC-IP> on the headset. Use a PC address the headset can reach (with Steam Link's dongle/AP that is the PC's address on the Frame's own subnet, e.g. 10.35.78.x; check with ping). Optional auto-start: scripts/frameeyeosc.service (systemd user unit).
5. Windows Firewall must allow inbound UDP 9020 to VRCFaceTracking.ModuleProcess.exe.

Logs and traces (PC): %TEMP%\steamframe-module.log, %TEMP%\steamframe-trace.csv.

Tuning

Every eye reports different "open" and "closed" levels (for example closed 0.17 on the left vs 0.33 on the right), so the module calibrates each eyelid separately. Tune it with a guided session:

python tools/tune.py record            # spoken prompts (works inside the headset): open, close, wink L/R, blink, look
python tools/tune.py analyze --apply   # measures levels, checks winks/blinks, writes the module config
python tools/tune.py watch             # live raw vs output eyelids
python tools/tune.py show              # current config

record stores timestamped labels with the trace, so every stretch of data has a known ground truth. The module hot-reloads steamframe-config.json (next to the module DLL) within a second, no restart needed:

key	meaning
lid.leftClosed/leftOpen/rightClosed/rightOpen	fixed per-eye calibration in raw tracker units (null = adapt automatically)
lid.deadband	fraction of the range at each end that reads fully closed / open
wink.threshold / range / strength	amplify left/right asymmetry (0 strength = off)
blink.holdMs / releasePerSec	hold the lowest lid value briefly so fast blinks reach full depth
gaze.scale / invertX / invertY, swapEyes	gaze scaling and orientation fixes

Troubleshooting

• Winking closes both avatar eyes: the avatar itself may link the eyelids. Look for an "Eye Sync" / "Link eyes" toggle in its menu (some VRCFT avatar templates expose FT/EyeSync) and turn it off. The module and VRCFT send the two lids independently.
• No module process / no data: start VRCFT through Steam, make sure the stock SteamLink module is not installed (UDP 9015 clash), and check %TEMP%\steamframe-module.log.
• frameeyeosc refuses to start: it needs shared-memory ABI version 4; after a Frame update the layout may have changed.

Known limits

• The tracker couples the eyes: closing one eye pulls the other toward half-closed, and in our tests a right-eye wink also lowered the left lid. Wink sharpening helps but cannot remove it.
• VRCFT sends EyeLid = openness x 0.75 (0.75 is normal open, above that means wide); that is VRCFT's convention, not a bug.
• Gaze scale (frameeyeosc sends +-1 for +-45 degrees) is converted to radians the same way as the Steam Link path; it has not been verified against a reference.
• No mouth or lower-face tracking: the Frame has no hardware for it.

Credits

• frameeyeosc (MIT) by konsti219 reads the Frame's eye data. It is cloned and built on the headset by scripts/headset-setup.sh, not vendored here.
• LinkFT (MIT) by ykeara, the Steam Link VRCFT module this one is modelled on.
• VRCFaceTracking by benaclejames.

License

MIT, see LICENSE.