In an interesting case of software pushing the limits of hardware, Valve recently updated SteamVR Tracking code to account for the speed of high-level Beat Saber players.

At first glance it might not be apparent, but Beat Saber is an excellent challenge for a VR controller tracking system. You might think that a fast-paced VR shooter or sword fighting game would be the game that would be pushing SteamVR Tracking to its limits, but Beat Saber is actually far more demanding.

In a recent update to SteamVR Beta (which will soon roll out to the SteamVR main branch), the following sentence appeared in the patchnotes:

Increase limits of what we thought was humanly possible for controller motion based on tracking data from Beat Saber experts.

Though it seemed like it might have been just a joke, Valve developer Ben Jackson offered up some detail in the comments:

The tracking system has internal sanity checks to identify when things go wrong. For example, if our math says you are behind your only basestation, clearly we made a mistake, because we wouldn’t be getting any signal from behind the basestation. One of these checks relates to how fast we thought it was physically possible for someone to turn their wrist. It turns out that a properly motivated human using a light enough controller could go faster (3600 degrees/sec!) than we thought.

Essentially, Valve built a number of assumptions into the SteamVR Tracking code so that it can identify clearly erroneous data (like a controller signaling that it is moving way faster than should be possible). However, it seems that one of those assumptions was actually too low for the speed of some high-level Beat Saber players, and Valve has now adjusted the code accordingly.

The main reason why Beat Saber manages to push the limits of VR controller tracking so effectively is not just because of the top speed of a player’s hands, but because of the drastic changes in acceleration when players are whipping their hands back and forth to cut distant notes on time.

Most VR controller tracking systems use two tracking methods and combine them together. The first system is an IMU inside each controller which senses rotation and translation, and can do so with low low latency and high frequency. The issue however is that IMU’s are prone to ‘drift’, so they can’t be relied upon alone for tracking. That’s where the other tracking method comes in: in the case of SteamVR Tracking, that’s the external ‘basestations’ which are used to establish the absolute position and rotation of the tracked object and to correct for drift from the IMU. However, the basestations update slowly compared to how fast the IMUs are (in the ballpark of 100Hz vs. 1,000Hz), and until that next positional correction comes in, all the tracking is up to the IMU.

In many cases, the moments of tracking between position corrections is aided by prediction, which uses prior motion to project where the tracked object is heading next. When moving slowly or drawing predictable arcs through the air, this works well. But Beat Saber is something of a worse-case scenario for that prediction because there’s no way for the tracking system to predict when the player is about to suddenly and completely reverse the direction of their controller (which happens constantly in the game, especially at higher levels).

Despite the challenge, SteamVR Tracking has held up extremely well to Beat Saber’s tracking needs except, it seems, in some edge cases which have now been patched. It’s frankly pretty amazing that the system manages to work as well as it does for the game; Valve ought to be pretty happy that they chose to aim for such a high tracking performance threshold from the outset.

Tundra Labs is releasing a new SteamVR Tracking hardware development kit. Featuring a tiny new module which condenses the necessary control, processing, and communication components into a mere 16mm × 10mm, the hardware development kit is smaller and cheaper, and aims to streamline the process of designing VR controllers and peripherals that use SteamVR Tracking.

Available for pre-order today, the new Tundra Labs SteamVR Tracking General Purpose HDK (TL448K6D-GP-HDK) is the next step in a continued evolution of smaller, simpler, and cheaper SteamVR Tracking hardware.

“Many companies and developers have recognized that SteamVR Tracking is excellent tracking technology,” said Reid Wender of Triad Semiconductor, a collaborator on the HDK. “Unfortunately, integrating SteamVR Tracking into a working product is a non-trivial task that involves a multidisciplinary team to pull off a polished product. Customers need SteamVR Tracking expertise, electronics prototyping, tracked object mechanical/tracking design, and last but certainly not least, SteamVR-specific firmware development. Even large companies have experienced difficulty pulling all of this expertise together under one roof.”

SteamVR Tracking is Valve’s room-scale tracking system which makes use of ‘base stations’ that sweep lasers across the room. Objects tracked by the system need two primary things: embedded sensors which detect the laser sweeps, and components which can process the data and communicate with a host device which will make use of the information.

The Tundra Labs SteamVR Tracking HDK aims to streamline things across the board by providing a cheaper and easier starting point for companies that want to build products with SteamVR Tracking.

The HDK includes a new module which condenses many of the necessary components into a tiny ‘system in package’ (SIP) measuring just 16mm × 10mm. The module contains the SteamVR Tracking firmware and handles all of the necessary data processing for the tracked object before it gets sent to the host device.

On the sensor side, the Tundra Labs HDK features 25 of the latest TS4112 sensors from Triad Semiconductor, another company which has worked closely with Valve on SteamVR Tracking. Triad says that its latest sensors are smaller, more power efficient, and offer improved tracking performance.

With shipping expected to start next month, the $130 Tundra Labs SteamVR Tracking HDK is significantly cheaper than a similar HDK previously offered by Triad for $350. Its core module is also much smaller, enabling new form-factors, like Logitech’s VR stylus.

Tundra Labs founder Luke Beno believes the cost and simplicity of the HDK opens the door for SteamVR Tracking development to go beyond large companies with expansive resources.

“The low cost reference designs also greatly lower the barrier of entry for startups, students, makers, and hobbyists to experiment with the SteamVR Tracking technology and share their ideas. Tundra Labs has created online communities at Hackaday.io and Hackster.io where innovative minds can experiment with new designs, share them and potentially connect these concepts and ideas with manufacturers.”

Beyond its SteamVR Tracking HDK, Tundra Labs also offers custom design services for companies who want to build products with SteamVR Tracking, and sells the SIP module for companies who need the component for mass production of tracked peripherals.

“The Tundra Labs [SIP] was created to make the design and manufacturing of SteamVR Tracked devices easier, lower cost and with significantly faster time to market,” Tundra Labs writes on its website. “For the first time these modules offer a fully scalable production solution to satisfy any volume. This scale spans from niche devices built in the 10s of units to mass market consumer devices with volumes of 100,000 or more.”

While the latest Tundra Labs SteamVR Tracking HDK is built for general purpose use-cases, the company also plans to release application-specific reference designs in the future.

“These could be used for body tracking or alternative controller form factors, ultimately the target use will be determined by customer interest and feedback,” said Beno. “The goal of all reference designs is to leverage the extensibility of [SteamVR Tracking] and the [SIP] to enable a diverse set of accessories into the ecosystem for both consumer and enterprise purposes.”

In an interesting bit of news which shows Valve’s SteamVR Tracking technology used in a non-VR application, robotics company Wandelbots has raised a $30 million Series B investment around their TracePen tool, a motion-tracked stylus which makes it easy to program the complex movements of industrial robots.

When Valve first introduced its SteamVR Tracking technology (formerly called Lighthouse) in 2015, the company said it envisioned the system being like ‘wi-fi for motion tracking’, in the sense that any device could make use of a shared tracking volume—including non-VR devices.

Germany-based Wandelbots is leveraging the tracking technology for its TracePen product which is designed to make programming industrial robots easier and faster. The company believes that lowering the barrier to robotic programming will enable wider use of robotic automation among companies that haven’t adopted the technology.

The TracePen product is a kit which includes the stylus (equipped with SteamVR Tracking sensors) and two SteamVR Tracking Base Stations. After setting up the Base Stations and calibrating the movement of the robot by attaching the stylus, the user can use the stylus to simply draw the route the robot should take for its task.

Typically defining these positions would require remote controlling the robot and using 2DOF inputs to guide the arm into each desired position. With full 6DOF tracking of the TracePen and sub-mm accuracy thanks to SteamVR Tracking, defining the positions is as easy as pointing to them with the stylus.

Once the positions have been defined, the robot can remember and return to them without the need for the Base Stations (thanks to its own IK tracking), which means a single TracePen system can be used to program any number of robots.

Last month, Wandelbots raised a $30 million investment to expand its operations, TechCrunch reported.

SteamVR Tracking is far from the first motion tracking technology to be used for industrial use-cases, but its comparatively extreme portability and low cost make it uniquely suited to this application. Other tracking systems like OptiTrack can offer greater tracking performance but require more expensive and complex setups.

The unique architecture of SteamVR Tracking is a significant reason for its versatility; most active tracking systems require the tracked object to be able to communicate with the thing that is tracking them. In the case of SteamVR Tracking, the external base stations don’t need to know anything about the tracked object. They simply send out a signal which can be be used for tracking by any object in the volume, without any ‘pairing’ procedures or any centralized host (ie: you could have several devices with independent compute tracked in the same volume at the same time).

Wandelbots TracePen also isn’t the first non-consumer application of SteamVR Tracking outside of headsets. Logitech for instance has created a VR stylus, which uses Valve’s tracking tech and is designed to be a more precise input device than the VR controllers that come with consumer VR headsets. Companies like Tundra Labs sell hardware which any company can use to build a product based on SteamVR Tracking, and HTC’s Vive Tracker is a general-purpose tracking puck which can be used to add SteamVR Tracking to anything.

Tundra Tracker, the upcoming SteamVR tracker alternative to the Vive Tracker, was originally expected to hold a Kickstarter in January, but the company behind the project, Tundra Labs, says the crowdfunding campaign has been pushed back in light of delays in component sourcing.

In the latest official update on the project, Tundra Labs notes, “Right now the semiconductor industry is going through incredible supply shortages due to a ‘double whammy’ of dropping factory capacity due to COVID-19 and skyrocketing demand also due to the pandemic. For this reason, since November 2020, we have been tracking components used in the Tundra Tracker and many are showing 26 to 30 week lead time for high volume deliveries. This means that If we place orders today, components may not be delivered until August. Thankfully we already started placing component orders in Q4 of 2020. We are also working directly with vendors to ‘pull in’ deliveries as much as possible and pay expedites when available.”

Given the long lead time, Tundra Labs says it has opted to delay the Kickstarter campaign to “shorten the time between when crowdfunding ends and when all backers receive their orders.”

The company now plans to launch the Kickstarter on March 29th for 30 days, and expects the first units to start shipping to early-bird backers starting in mid-June, while the bulk of backers can expect shipments in mid-September.

Beyond Kickstart plans, the company also revealed some more details on the Tundra Tracker’s design, including a closer look at how the swappable base plates will work.

“The rendering above demonstrates the production product design, especially about the swappable baseplates for Tundra Tracker. Based on feedback there will (at minimum) be options for an integrated strap loop baseplate as well as a backwards compatible with 1/4-20 mounts.” The company says it’s investigating additional base plates for other uses.

Tundra Labs also shared the first look at a functional prototype in action:

In addition to being smaller and lighter, Tundra Labs is aiming to make the price of the Tundra Tracker slightly less than the Vive Tracker, though pricing hasn’t been finalized yet. “We are still resolving the pricing question,” the company said in its latest update.

Varjo just announced its latest headset, the XR-4, and while the company is primarily continuing to target high-end enterprise use-cases, this is the first headset in their ‘XR’ series that they will sell directly to consumers and without a hefty annual fee that was once required to use the headset.

Released back in 2021, Varjo Aero is the company’s first and only prosumer-positioned headset. Though high-end, it has also been a lesser-speced headset than the company’s flagship devices.

The new Varjo XR-4 is the latest headset from the company that has focused on creating the highest-fidelity tethered headset on the market. While the headset’s $4,000 price tag is surely targeting high-end enterprise use-cases, for the handful of prosumers out there who have cash to burn, XR-4 is actually the cheapest of the company’s enterprise-positioned headsets yet. It’s also the first of Varjo’s XR-series headsets that the company will sell directly to consumers and without a required annual fee.

For now the company is soliciting invitations to join the consumer waitlist for the XR-4, saying those on the list will be alerted when the headset is available in their given country.

Varjo XR-4 with SteamVR Tracking

While XR-4 has its own inside-out tracking system, the company is also making a variant of the headset which ties it into the SteamVR Tracking ecosystem (as its prior headsets once relied upon).

Unfortunately it’ll bring the price of the base variant of the headset up by another $1,000. Varjo has confirmed that this variant of XR-4 can switch back and forth between SteamVR Tracking and the headset’s own inside-out tracking.

It’s potentially also possible to eschew the $1,000 addition and instead add SteamVR Tracking to the base variant of XR-4 by attaching something like the Tundra Tracker and configuring it to represent the position of the headset. Though this will take a few extra steps compared to having SteamVR Tracking built right in.