What causes hand-tracking fingers stuck fully open in VR?

The hand rig is posed from a static default skeleton instead of the live per-joint tracking poses, so the fingers never curl.

How do I catch this when it only happens for some players?

Capture it automatically from the player's device with the full stack trace, the device and OS, the build, and a breadcrumb trail of what they did. That turns a vague complaint into a specific, reproducible issue you can fix without owning the hardware it happens on.

How to Fix Hand-Tracking Fingers Stuck Fully Open in VR

Quick answer: Drive each finger bone from the XR Hands subsystem joint poses every frame, mapping tracked joint rotations onto your hand rig's bones.

Hand presence depends on the modeled fingers following the player's real finger curl. If you only attach a static hand mesh to the wrist pose, the fingers stay frozen open. The hand-tracking API exposes per-joint poses you must apply to each finger bone to get real curl and pinch.

How to fix it

1. Read the joint poses

Use the XR Hands subsystem (or platform hand API) to read each finger joint's pose every frame while tracking is valid.

2. Map joints to bones

Apply the tracked joint rotations to the corresponding bones of your hand rig so knuckles and fingertips curl with the player.

3. Handle tracking loss

When the hand loses tracking, freeze or fade the last good pose instead of snapping back to the open default, which looks broken.

Catching the ones you can't reproduce

The hardest version of this to fix is the one you can't reproduce — it only happens on a player's hardware, OS, driver, or save state, under conditions that simply aren't present on your machine. A report that says “it crashed” or “it froze” gives you nothing to act on, so the bug survives release after release while quietly costing you players.

Automatic error capture closes that gap. Each failure arrives with its full stack trace, the device and OS, the build number, and a breadcrumb trail of what the player did right before it broke, so even a failure you have never seen becomes a specific, reproducible issue. Fold identical failures into one signature ranked by how many players each hits, and your worklist sorts itself worst-first instead of arriving as a stream of vague complaints.

This is where a tool like Bugnet earns its place. Its SDK captures every error automatically with the full stack trace plus device, OS, memory, build, and game-state context, folds duplicates into one grouped issue with an occurrence count, and ties each to the build it first appeared on — so you fix the problem that hurts the most players first and confirm it is gone when its signature disappears from the next release.

Most of the time the fix is small. Seeing the failure clearly is the part that actually costs you.