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We take a seat on Turris' VR Chair


You spin it round like a record
— 2:44 PM on April 28, 2016

VR is the Next Big Thing in computing right now, but I don't own my own VR hardware yet. I consider myself an early—but cautious—adopter. I didn't back the Rift's Kickstarter or preorder HTC's Vive, but not for a lack of interest. I'm actually fascinated by this new wave of VR and augmented-reality, or AR, technology. One reason I find them so intriguing is the vast untapped potential of these fields. My personal interest was piqued when I read The Atopia Chronicles in early 2013. That book's modern take on AR got my head spinning. I think it should be required reading for VR and AR developers, but I digress.

Another large part of my fascination with VR stems from watching PC hardware and software developers grapple with the problems that VR introduces. I know I'm not alone in feeling thankful for something that's pushing the envelope on optimization of software and drivers. Many of the usual suspects are already doing their part. Nvidia and AMD are working closely with Oculus, as well as HTC and Valve, to release drivers that improve the VR experience. Heavy hitting game developers like Epic, Unity Technologies, and Crytek have added VR support to their engines to varying degrees, as well.


Gato 2.0 approves - or does he? Also, he heard something about gerbils?

Just because the biggest players are already firmly seated doesn't mean there isn't room for newcomers, though. Whether you think VR is a new industry, a bunch of companies turning an existing one on its ear, or just a fad, there's no denying it attracts a lot of attention. Tons of investors, inventors, and entrepreneurs are trying to make VR the next big thing.

One of those inventors, Aaron Schradin, happens to be a good friend of mine. His device, the Turris, is meant to change the way we traverse VR environments. I've had the opportunity to watch the Turris develop as it's made the rounds to SXSW and other conventions for over a year now. I thought it was about time I took advantage of my insider connection to share a TR-exclusive in-depth preview.


If I had one of these, I'd display it a little more prominently.

A little background information
Thanks in part to TR, Aaron got connected with AMD during the launch-hype surrounding that company's Dragon Platform back in 2008. I still remember him telling some of AMD's best extreme overclockers how they were doing it wrong, and it still makes me chuckle to this day. From there, Aaron consulted with AMD and eventually developed a number of custom cooling pots for extreme overclocking, including a see-through lexan pot for LN2 and a pot specifically designed for liquid helium that was eventually used to set a world record for CPU clock speed when Bulldozer launched. The industry connections he made around this time eventually pulled him into the world of VR, where another "you're doing it wrong" moment lead to the founding of his company, Praevidi, and the creation of the Turris.

The concept behind the Turris is pretty straightforward: you sit on it, and your movement in VR space mimics your real-world movement. Tilting forward, backward, left and right moves your character in those directions, and rotating the chair rotates your character 1:1 in VR. The buzzword that makes these abilities important is de-coupling. In engines that support it, de-coupling means that your torso's position and direction is tracked separately from where your head is looking. It's a function that sounds simple on paper, but it's kind of a big deal for the industry, especially for seated applications like the Rift. Take a look at the impromptu video below for a demonstration (my apologies for the small on-screen character size—it's probably best to watch in full-screen so you can actually see that detail).


TL;DR version right here...

How does it work?
The Turris appears as an Xinput-compatible device when it's hooked up to the PC (in short, like an Xbox 360 controller). The directional inputs from the seat are interpreted as digital, WASD-style movement of the left thumbstick. The rotational movement is similarly interpreted as left or right movement of the right thumbstick, depending on the direction of rotation. According to Aaron, this means that any developer in possession of an Xbox controller already owns a Turris dev kit.

In its current form, the switches on the Turris are mounted into 3D-printed springboards designed to prevent them from being overly stressed when they are actuated. There's a few other details hidden under the seat, as well. Bolts with rubber caps act as the seat's fulcrums. These bolts can be adjusted to fine-tune the amount of tilt required to initiate movement, kind of like adjustable weights in a mouse. The same adjustments can also be used to compensate for differences in user height, weight, and seating posture, since those variables all affect the location of the user's center of gravity.


A glimpse under the cushion.

There are also hard stops around the outside edge of the base that line up with adjustable steps under the top of the seat. These stops work in conjunction with the fulcrums to limit the maximum amount of tilt. That adjustment range is important when you're using your body weight to control fine movement in VR, because you want to make the subtlest adjustments possible. If your center of gravity is allowed to shift too far in any direction, it requires at least that much more movement to change directions back again.

Aaron tells me that he's also tested switches that have two different actuation points. Those switches could mean that shifting further in a direction could change movement from a walk to a run. That makes nailing the per-user adjustability of the seat all the more critical. He's also gotten the Turris working with gyroscopic-motion-controls (an MPU-6050, for the curious) to allow for more analog-style control of speed and direction, but users have so far preferred the simpler and more predictable movement that comes from the on/off toggle of digital switches.

 
Aaron explains the Turris to TR gerbil Sheldomaus.

The Turris tracks rotational movement with a black-and-white ring in its base. An optical encoder in the free-spinning section tracks this ring as the chair moves. The encoder tracks the absolute angle and position of the chair in 2.8-degree increments. If you do the math, that means the chair can occupy 128 unique positions throughout its 360º rotation. Aaron says that the 2.8-degree value is the sweet spot for balancing granularity of movement and avoiding unintentional judder that could lead to motion sickness. Since the Turris is still in development, though, these parameters are still being tweaked.