PiHead 3DOF vs 6DOF head tracking: which one do you need?
When comparing head trackers you often run into "3DOF" and "6DOF". DOF stands for degrees of freedom. In short, it tells you how many different head movements a device measures. This post explains the difference between the two, what helps in which game, and where PiHead Tracker stands.
Three rotation axes
Your head can rotate in three ways:
- Yaw: turning left and right, as if saying "no".
- Pitch: looking up and down, as if saying "yes".
- Roll: tilting your head sideways, bringing your ear towards your shoulder.
Devices that measure only these three rotations are called 3DOF. Most sensor-based head trackers fall into this group, and so does PiHead Tracker.
Three position axes
Besides rotating, your head can also move: leaning forwards and backwards, sliding left and right, rising and sinking. Systems that measure these three positions on top of rotation are called 6DOF. Infrared camera systems like TrackIR and some webcam solutions can measure position, because they see your head from the outside.
Measuring position is hard for a sensor-based device. Getting position from an accelerometer means adding up the measurement twice, and even the smallest error turns into metres of drift within seconds. That's why camera-free devices focus on rotation instead of position.
How much games use position
| Game type | Importance of position | Why |
|---|---|---|
| Truck and car sims | Low | Checking mirrors and looking sideways is done by rotating. Leaning forward helps a bit at junctions but isn't essential. |
| Civil flying | Medium | Position is nice for leaning towards the panel, but the game's zoom key does that too. |
| Combat flying | Medium to high | Shifting your head sideways helps you see behind the canopy frame. |
| Space and military sims | Low to medium | Depends on the game's design. |
In short, most everyday use is rotation. Position tracking makes a difference mostly in flight sims, and especially in combat flying.
How the neck model closes the gap
In real life your eyes don't rotate in place when you turn your head. Your head rotates around your neck, so your eyes move along a small arc. When you look right, your eyes shift a few centimetres right and back. On a device without position, that small shift disappears too and the view feels like it rotates around a single point.
The experimental Neck model option in PiHead Tracker calculates that shift from your head angle and sends it to the game as position. This isn't real position tracking; for example, it doesn't measure leaning forward. But it makes looking to the side feel natural. In games that support position (like ETS2 and MSFS), you can turn it on in the app's In-game section.
Which one to choose
- If you mostly play truck, car or civil flight sims, 3DOF is very likely enough. The convenience of a device that needs no camera or light matters more than the missing position.
- If you lean around the cockpit a lot in combat flight sims, you'll feel the benefit of 6DOF. In that case a camera-based system may suit you better.
- If the lighting in your room changes often or there's no room for a camera on your desk, a camera-free 3DOF device makes life easier.
We made PiHead Tracker 3DOF on purpose, and we say so clearly on the product page. You'll find a comparison of head tracking methods in our head tracking guide.