Why Did Full-Body VR Trackers Start Adding Cameras? The 2026 Move to Hybrids
Full-body tracking in VR — getting your hips and feet onto your avatar — has long been split between two approaches. IMU trackers strap sensors to your body and infer posture from them; camera-based systems film you and work out where your limbs are. Since the start of 2026, though, products that mix the two have been arriving one after another. What is going on in this corner of the market?
This article looks at what has happened to trackers in 2026 and why manufacturers have started combining both methods.
Researched as of July 2026.
IMU vs camera: what each is good and bad at
| IMU | Camera | |
|---|---|---|
| How it works | Sensors on the body detect movement | A camera films the body and derives posture |
| Examples | HaritoraX 2, SlimeVR | Webcam-based software, VIVE Ultimate Tracker |
| Strength | Unaffected when hidden behind the body. Fast response | Knows absolute position. Error does not accumulate |
| Weakness | Orientation drifts over time | Cannot see what is out of frame. Higher latency |
The IMU weakness is that orientation slowly slips as you use it. The sensors derive posture by accumulating “how much did I rotate", so small errors pile up. If you have done full-body tracking, that is the effect where your hips end up facing somewhere other than where you are facing after a while.
Camera systems, as long as your body is in frame, know where you actually are, so nothing accumulates. But they cannot infer what they cannot see, and things fall apart when you put a limb behind your back.
The two weaknesses point in opposite directions. That is the starting point of this story.
What happened to the HaritoraX 2? An add-on that bolts a camera on
In May 2026, Shiftall announced “Add-on R", an expansion kit for the HaritoraX 2, and shipping began in July 2026. It bolts an infrared camera onto the flagship IMU tracker to correct drift.
| Price | ¥19,900 (incl. tax, Japan) |
| In the box | One infrared camera, six reflective plates, USB cable |
| Compatibility | HaritoraX 2 / 2 Pro / HaritoraX Wireless (different SKU for Wireless) |
| Requirements | Windows 11, USB 2.0 |
| Space needed | From 1.5m × 1.5m, vertical placement |
The mechanism is the interesting part. You stick a reflective plate on each sensor, and the plate only has to be in view of the camera for 0.1 seconds for the system to compute and correct that sensor’s drift. While a sensor is out of frame, it runs on IMU alone as before.
In other words, nothing has to stay in view continuously. It dodges the camera weakness — “if I cannot see it, I do not know" — while removing only the IMU weakness, the accumulating drift.
There are constraints. Fitting the reflective plates disables the HaritoraX 2’s ankle detection, because the plates interfere with the distance sensor. You also carry the extra weight of six plates.
Together with the tracker itself, that is HaritoraX 2 (¥39,999) + Add-on R (¥19,900) = ¥59,899. Existing owners being able to add it later is part of the appeal.
Is anyone else doing this? More than one company
Opsens+ (Uni-motion) — hybrid from the start
A Japanese tracker released in November 2025, combining optical correction that reads AR markers with a camera and a 9-axis IMU. The 6-sensor Opsens+ is ¥54,780. A hybrid mode was added in June 2026 and the management software was updated in July.
It is said to run about 400 hours on AA batteries, which stands out. That figure is the manufacturer’s own, though — I could not find third-party verification.
One caution: there are reports that the official management software has stayed in beta for more than six months after release, with the older software still recommended in practice.
SlimeVR — prototyping a camera base station
SlimeVR, the other IMU flagship, has said it is prototyping a system that pairs a camera-type base station with its IMUs.
Note that SlimeVR’s new “Butterfly" tracker — which raised more than seven times its crowdfunding goal — has slipped from end of August 2026 to end of October 2026, attributed to delays in tooling for the case. Every review out so far is of a prototype; there are no third-party reviews of the production unit yet.
VIVE Ultimate Tracker — camera-based from the beginning
Here the camera is in the tracker itself, which looks at the surroundings to work out its own position. No external base stations required, and it has used cameras since launch.
Why does mixing help? The weaknesses point opposite ways
| IMU | Camera | Mixed | |
|---|---|---|---|
| Absolute position | Unknown (drift accumulates) | Known | Camera’s job |
| Tracking fast movement | Fast | Lags | IMU’s job |
| Limbs behind the body | Unaffected | Lost | IMU’s job |
IMUs are quick at catching changes in movement but have no way of knowing absolute orientation. Cameras know absolute position but lag, and cannot see what is hidden. What one is bad at, the other is good at.
Add-on R’s “0.1 seconds in view is enough" design expresses that relationship neatly. It does not ask the camera to track continuously; it gives the camera only the job of fixing the drift. The IMU handles ordinary movement, and now and then the camera checks its work.
What to buy: the options as of July 2026
| Option | Price (Japan) | Status |
|---|---|---|
| HaritoraX 2 | ¥39,999 | On sale. Add-on R can be added later |
| HaritoraX 2 + Add-on R | ¥59,899 | Shipping since July 2026 |
| HaritoraX 2 Pro | ¥53,899 | On sale |
| Opsens+ | ¥54,780 | On sale. Note the software caveat |
| PICO Motion Tracker | ¥11,800 | PICO headsets only |
| SlimeVR Butterfly | From ≈¥42,000 | Shipping end of October 2026 (delayed) |
For something you can buy now and extend later, HaritoraX 2 plus Add-on R looks the easiest to handle. You can also buy the tracker alone first and add the kit if drift starts to bother you.
If you already own a PICO headset, the Motion Tracker is cheap at ¥11,800. Note though that the PICO 4 Ultra itself was repriced in May 2026 from ¥89,800 to ¥104,900, so the total for a fresh setup has gone up.
Wrap-up
Looking at trackers released since the start of 2026, the very premise of treating IMU and camera as separate categories is fading. The HaritoraX 2, an IMU-only device, has gained a camera; Opsens+ carried both from the start; SlimeVR is prototyping a camera base station.
The reason looks simple: the two approaches have weaknesses that point in opposite directions. We seem to have reached the point where mixing them is straightforwardly better than picking one.
This article is a summary of published information; I did not test any of these devices myself. All figures are manufacturer-published values. Real-world performance will vary with your setup.