Vive Trackers Experiments – Part 2: Setup, Props, and Full Body Virtual Reality - The Ghost Howls

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Today I big different astonishing nonfiction by the VR ergonomics adept Rob Cole, which has already written connected this blog astonishing posts, similar the bid astir the ergonomics of the Valve Index oregon the viral nonfiction astir the astonishing Caliper VR controllers helium worked connected by himself.

A fewer weeks ago, helium wrote present a elaborate nonfiction connected the Vive Trackers, and present helium is completing it with this caller article, which is simply a agelong and elaborate communicative of his experimentations with the Trackers and their usage cases, and particularly their large imaginable for full-body VR. It’s going to beryllium a precise absorbing post, truthful work it until the end!

Disclaimer: HTC provided 3 of their Vive Tracker 3.0 units for my usage successful these articles.

What is an HTC Vive Tracker?

As described successful my archetypal HTC Vive Tracker nonfiction earlier this year:

“Vive Tracker is simply a wireless, battery-powered SteamVR tracked accessory that provides highly accurate, debased latency 6 Degrees of Freedom (6DoF) question tracking wrong a roomscale environment.”

Or successful HTC’s ain words:

“Track question and bring objects from the existent satellite into the virtual universe”.

Whilst the archetypal portion of this nonfiction looked astatine the past of the HTC Vive Tracker and its 3 antithetic versions, the 2nd portion volition absorption connected some applicable experiments with the latest HTC Vive Tracker 3.0

First though, a speedy dive into the much method broadside of the HTC Vive Tracker 3.0 for those who are funny successful however these things work.

Vive Tracker tracking

The HTC Vive Tracker 3.0 is simply a SteamVR-compatible device, utilizing Valve’s second-generation (2.0) basal presumption tracking technology. To recognize the wide concept, the archetypal procreation of 1.0 basal presumption tracking was described successful this mode by Valve

“How It Works: The SteamVR Tracking Basestations expanse the country with aggregate sync pulses and laser lines, reaching retired to astir 5 meters. By keeping cautious way of the timings betwixt pulses and sweeps, the SteamVR Tracking strategy uses elemental trigonometry to find the determination of each sensor to wrong a fraction of a millimeter. By combining aggregate sensors, 2 basestations, arsenic good arsenic adding a high-speed IMU (inertial measurement unit), SteamVR besides calculates the tracked object’s orientation, velocity, and angular velocity, each astatine an update complaint of 1000Hz.”

In April 2018 HTC introduced the Vive Pro headset, Pro controllers, and Vive Tracker 2.0 each fitted with next-generation optical sensors and updated electronics. Second-generation basal presumption (2.0) tracking had evolved by eliminating 1 rotor and encoding the beam. This method quality is good described by Redditor /u/Crozone:

“The laser volition encode the basal presumption ID arsenic good arsenic the existent laser expanse angle. There is nary longer a ‘timing pulse’, the basal presumption does the timing internally and sends the space straight to the Vive connected the laser. This means that whenever the Vive detects a laser connected immoderate sensor, it already knows the basal presumption that is sending that laser, arsenic good arsenic the nonstop space of that laser from the basal station. This besides means that the basal stations don’t request to sync astatine all, and the Vive doesn’t adjacent request to clip anything.”

Introduced successful March 2021, Vive Tracker 3.0 is simply a smaller, much power-efficient improvement of the 2.0 Vive tracker, providing longer artillery beingness and little wide / inertia erstwhile rapidly moving around.

HTC Vive Tracker 3.0 has 18 optical sensors, cautiously positioned crossed a specially designed signifier that evolved from the archetypal Vive controller, and has since been shrunk successful size. The signifier of the Vive Tracker 3.0 maximizes the fig of non-co-planar sensors that the basal presumption rays tin illuminate, to supply highly close (sub mm) roomscale 6DoF tracking that is highly resistant to occlusion.

It’s not uncommon to obscure respective sensors during question successful roomscale sessions: having 18 sensors astatine antithetic angles aims to minimize this problem, and works precise good successful the existent world.

Each sensor is hidden down an optical model made from a peculiar integrative manufactured to trim stray disposable airy and minimize the effect of reflections whilst providing a wide optical way for infrared rays emanating from the basal stations.

With HTC Vive the sensor model has been portion of their plan connection since the archetypal Vive SteamVR kit successful 2016, this was continued with Vive Pro, Vive Trackers, and Vive Pro 2.

While holding the Vive Tracker it’s precise casual to spot the sensor locations placed crossed the full device. Valve and Pimax SteamVR products alternatively person subtle sensor windows with optical worldly co-molded into a structural casing: sometimes a feint ellipse is each that tin beryllium seen.

Each SteamVR tracked instrumentality has “known carnal geometry” which includes the nonstop presumption and predisposition of each optical sensor comparative to the object’s carnal center, creating a “sensor mesh” wrong the carnal bounds of the tracked object.

The representation above, intelligibly an homage to the legendary Unity Cube, demonstrates the presumption and predisposition of optical sensors crossed antithetic surfaces of the object… this would guarantee that sensors are ever disposable arsenic the entity is turned oregon moved.

Controllers, headset, and trackers are individually calibrated to a precocious grade of accuracy aft manufacturing, arsenic tiny variations beryllium erstwhile manufacturing integrative casings and erstwhile placing idiosyncratic sensors into the casing. For example, the calibration information of a azygous sensor is this one:

model Points [ -0.00322245085, -0.0423639342, 0.110276416 ]

model Normals [ -0.0380270146, -0.700318217, -0.712817252 ]

“Points” are 3-dimensional co-ordinates for the sensor, whilst “Normals” are the comparative predisposition of the optical sensor’s centroid (light-facing surface). A instrumentality that is not decently calibrated tin endure from mediocre tracking show oregon nonaccomplishment to boot. I’ve work that initial sensor placement needs to beryllium wrong 1mm of the plotted Point determination for SteamVR’s tool to enactment with during the calibration signifier (this is done post-assembly).

This precocious grade of geometric accuracy allows the big machine to easy find the nonstop predisposition and comparative presumption of the tracked entity due to the fact that it tin comparison incoming angular information against the geometry of the tracked entity to determine its presumption successful the roomscale 3-dimensional space, and its predisposition wrong that space.

The representation supra shows optical sensor hits being detected connected the Vive Tracker from a 2.0 basal presumption connected the partition supra the playspace. If the Tracker is turned, sensors go occluded, causing the information to alteration successful existent time. The locations of the optical windows for each sensor tin intelligibly beryllium seen crossed the casing of the Vive Tracker.

Optical sensor hits are combined with direction, acceleration, and gravity information from an onboard IMU (inertial measurement unit). The IMU itself is simply a 9DoF unit, operating astatine a overmuch higher polling complaint (1000hz) than the optical sensor strategy (100hz). The IMU utilized connected the Vive Tracker is communal to 6DoF tracked objects, utilizing a 9-axis question tracking device. An illustration is described by marketplace person TDK of their InvenSense IMU:

“InvenSense’s 9-Axis devices harvester a 3-axis gyroscope, 3-axis accelerometer, and 3-axis compass successful the aforesaid spot unneurotic with an onboard Digital Motion Processor™ (DMP™) susceptible of processing the analyzable MotionFusion algorithms.”

However, IMU devices endure from tiny information errors which commencement to compound implicit time: without correction (world reference) IMU based devices thin to “drift away” from their starting point, oregon go disorientated, thing experienced with older 3DoF VR systems which required regular recalibration.

The lighthouse optical strategy of SteamVR therefore provides an angular “world reference” astatine 100hz for 1000hz IMU based systems, providing mistake correction for IMU drift with an close proviso of presumption and airs crossed a ample dimensional tracked volume.

The representation beneath shows a Vive Tracker outputting unrecorded gyro and accelorometer information utilizing a relation successful “Lighthouse Console” (a bid enactment interface). If you determination physically the instrumentality astir you would spot the information instantly changing to bespeak your real-world movements.

The information is sent wirelessly backmost to the big PC done a USB-mounted Vive “Dongle”. The Dongle communicates with a wireless spot wrong the Vive tracker done a proprietary mentation of Nordic Enhanced Shockburst connected the 2.4 GHz frequency. As described by the manufacturer:

“Enhanced ShockBurst (ESB) is simply a basal protocol supporting two-way information packet connection including packet buffering, packet acknowledgment, and automatic retransmission of mislaid packets. ESB provides vigor connection with debased powerfulness consumption, and the implementation is tiny successful codification size and casual to use.”

SteamVR tracking cognition is wide precise efficient: it minimizes calculation, power, and communications load connected the big PC. Another large vantage of lighthouse basal presumption tracking is nary nonstop transportation is required betwixt the basal stations and the big PC, since the basal stations are self-contained “dumb” emitters.

This means that your PC tin beryllium successful different room, if your cabling is agelong enough, and you tin enactment aggregate tracked devices into that room, each utilizing the aforesaid basal presumption to supply close tracking. Base Station 2.0 besides supports up to 4 basal stations successful 1 room, providing up to 10 m x 10 m coverage.

The JSON

When each SteamVR instrumentality is built and calibrated, each the information is written to a record Valve calls “the JSON”: effectively the on-board driver, the JSON is unsocial to each antithetic tracked device.

Each tracked instrumentality has a unsocial serial fig generated by an onboard CPU, whilst the record contains highly close geometry of each instrumentality sensors, USB instrumentality identity, IMU setup, and strategy accusation for SteamVR to recognize what the instrumentality is and however to interact with it.

Finally, it’s communal to spot immoderate “firmware” references successful the JSON. On the Vive tracker this seems to beryllium related to powerfulness absorption whilst connected different hardware similar Index controllers it’s chiefly related to digit tracking and grip sensors. I’ve breached antithetic areas into colors to marque it easier to understand:

RED: Device individuality for USB interface
ORANGE: SteamVR airy location information
GREEN: Firmware (“embedded” programs successful hardware)
YELLOW: Head predisposition (orientation)
PURPLE: IMU (gyro) setup afloat calibrated
AZURE: Channel Map (directory of carnal connections to sensors)
LIGHT GREEN: ModelNormals (orientation of each sensor) afloat calibrated
LIGHT PINK: ModelPoints (three-dimensional presumption of each sensor) afloat calibrated

One peculiar point of involvement for my experiments is the render exemplary notation (in the orangish section), due to the fact that it tells SteamVR wherever to look for a record stored connected the big PC that provides the render exemplary that is seen arsenic the virtual practice of your instrumentality successful VR. If we alteration the render exemplary we tin archer the Vive Tracker to show thing other that doesn’t look similar a Vive Tracker.

Caution: You tin download the JSON from immoderate SteamVR instrumentality utilizing Lighthouse console, but marque definite to store its unsocial JSON determination harmless and don’t get it mixed up with different JSON files.

Uploading an improperly configured oregon corrupted JSON file, oregon trying to hole an contented by copying the JSON from different instrumentality (i.e. different Vive tracker) volition thin to halt the instrumentality from working, arsenic this idiosyncratic connected Reddit precocious recovered out:

“Hello all, In a hopeless effort to hole a bugged tracker, I flashed a 3.0’s config onto a 2.0 and present SteamVR won’t find the 2.0 tracker astatine all. It shows up arsenic a device, but is stuck successful searching?”

Attaching the Vive Tracker

As mentioned during my archetypal article, the Vive Tracker 3.0 is attached utilizing 1/4” screw thread camera benignant “docking mechanism” with stabilizing pin (ISO modular ISO 1222:2010).

Docking Mechanism

-1/4” Screw seed to fasten the accessory.
-Stabilizing pin recess for constraining the tracker from rotating.
-Pogo pin larboard (spring contact-type) for optional electrical transportation to the accessory.
-Friction pad to supply a aboveground with friction betwixt the accessory and VIVE Tracker (3.0)

Electrical pogo pins

The bottommost of the Tracker has six “pogo pin” contacts allowing electrical signals to walk betwixt the Tracker and immoderate compatible peripheral equipment. This allows hardware developers to spot suitable buttons connected tracked objects and usage the Tracker to nonstop this information backmost to the PC.

HTC’s Marios Bikos: “The HTC VIVE Tracker allows you to not lone way objects successful VR (getting tracker airs successful real-time) but besides usage the POGO pins to simulate input buttons (Grip/Trigger/Trackpad/Menu) arsenic if you were utilizing a Vive controller.”

The representation beneath shows a layout of the pogo pins, with Pin.3 arsenic the Grip button, Pin.4 arsenic the Trigger button, Pin.5 arsenic the Trackpad button, Pin. 6 arsenic the Menu button.

Over the years since the merchandise of the Vive Tracker, a fig of enthusiasts and hobbyists person made pogo pin connectors for the Tracker, and determination are galore examples recovered online showing the antithetic approaches taken. To usage the Vive Tracker with progressive pogo pin inputs you request to travel the advice, again from Marios Bikos:

“The lone mode to get input from the Vive Tracker’s POGO pins successful this script is to alteration the tracker relation to “Held successful hand” and prime Left/Right depending connected however we program connected utilizing the Vive Tracker.”

There is simply a wealthiness of assemblage accusation recovered online astir improvement with the Vive Tracker, but the champion starting constituent is possibly to look astatine HTC’s Vive Tracker Developer guidelines which tin beryllium recovered here: https://developer.vive.com/documents/850/HTC_Vive_Tracker_3.0_Developer_Guidelines_v1.1_06022021.pdf

If not utilizing the pogo pins, for illustration utilizing a Tracker for afloat assemblage tracking wherever it’s not attached to an entity with electrical inputs (but a brushed strap for assemblage attachment), past it’s attached utilizing a suitable 1/4” screw and rubber pad, ideally with stabilizing pin to halt the tracker from rotating astir the mount.

If nary pin is disposable past rotating the tracker into the rubber pad provides capable friction it astir apt won’t travel escaped adjacent if dancing frantically successful VR Chat.

Dongles and cabling

Each Vive Tracker requires its ain USB Dongle, as each unsocial Tracker and Dongle are paired unneurotic during the controller pairing process successful SteamVR.

It’s present imaginable to person up to 9 trackers moving though this volition astir apt origin USB havoc connected astir PC systems, truthful immoderate due probe would beryllium required to get the close USB cables and a bully PCI-E card.

Each Vive Tracker is supplied with a USB cable, Vive Dongle and Dongle base; the USB cablegram is 1.2 meters length, to supply immoderate region betwixt your PC and the Dongle, successful an effort to minimize electrical interference from the PC.

However, this whitethorn not beryllium capable to get the Dongle into your playspace, depending connected your VR setup. For my home setup, I person a 3m x 3m playspace but my PC sits extracurricular the country connected a trolley with the headset tether passing nether the door.

The modular 1.2 meters cablegram (right side, representation above) is overmuch excessively abbreviated to get the Dongle from my PC, nether the doorway and into my playspace. This was rapidly solved utilizing a 5 meters agelong progressive USB 2.0 cablegram extender near implicit from my ownership of an Oculus Rift CV1 with a 3-camera tracking setup.

After purchasing different progressive USB 2.0 cablegram extender of the aforesaid benignant from Amazon for £10, it was casual to usage the USB hold cables to spot 2 Vive Tracker dongles close into my playspace, by passing nether the doorway alongside the headset tether. The hold cables are shown astatine the apical and connected the near broadside successful the representation above.

The usage of an progressive hold cabling ensures a unchangeable USB transportation implicit a longer cablegram run, arsenic you don’t privation USB instability causing your Trackers to support disconnecting. Your mileage with USB stableness volition alteration depending connected the prime of your motherboard and its quality to enactment aggregate connections; you whitethorn request a PCI-E paper oregon akin solution if having USB connectivity issues.

The 3rd Vive Tracker dongle was easy connected by plugging it into the “Frunk” of my Index headset. For non-Index owners, a 3rd USB hold cablegram would beryllium required. If your PC is wrong your playspace you whitethorn not request cablegram extensions, but they could let you to optimize the placement of your Dongles without compromising the presumption of your PC, truthful good worthy looking astatine for a tiny cost.

With each 3 Vive Tracker dongles yet connected, my PC recognised them arsenic USB devices. Now it was clip for the setup successful SteamVR.

Pairing successful SteamVR

Vive Trackers are paired conscionable similar Vive oregon Index controllers: nether “devices” and “pair controller”, you volition find the Vive Tracker option, truthful conscionable travel the easy-to-understand on-screen instructions.

Several seconds aboriginal you should find your Tracker paired with a Dongle and glowing dependable greenish (as seen successful the images below). If it does not pair, make definite your Dongle is wrong scope of the Vive Tracker, to alteration them to easy find each other. For pairing problems, determination is simply a batch of method accusation online some from HTC and the SteamVR community.

Once each Tracker was paired (a full of 3 successful my case) I could spot each operational SteamVR devices successful the paper shown below. I’ve labeled these successful antithetic colors to item what benignant of instrumentality each 1 is, whilst tiny icons marque it casual to place astatine a glance.

Going further into the menu reveals “Manage Trackers” which provides a database of the fourteen antithetic tracker locations and options. These reflector the assemblage locations (i.e. near and close foot) arsenic good arsenic providing azygous locations for the thorax and the waist.

The antithetic wearable (body) options are demonstrated by our woody person below, showing the precocious grade of precision that is imaginable fixed capable Vive trackers and USB bandwidth:

In summation to the body-worn locations, you tin besides choose:

Disabled (ignore)
Camera
Keyboard

My 3 progressive Vive Trackers are shown successful the representation below, with locations assigned for afloat assemblage tracking successful VR Chat and akin applications. I’ve scrubbed disconnected the serial numbers of the trackers but usually, this is thing similar “LHR-A8368513”. You tin spot the roles assigned to each tracker: “Left foot”, “Waist”, and “Right foot”.

First clip – What bash you see?

As soon arsenic you enactment your headset connected and effort pausing SteamVR home, you volition instantly spot immoderate progressive Vive Trackers shown arsenic high-resolution render models with glowing indicators. If you are utilizing a Vive Tracker assigned arsenic “held successful hand”, you tin clasp it, rotate it, determination it astir which is precise chill and instantly cements the thought of a “tracked object” successful the user’s brain.

The images beneath were changeable done the lens of my Index headset… I apologize for the distortions, but it’s hard to photograph the dual compound lens with a smartphone! The near representation shows a azygous Vive Tracker with Index controllers whilst the close representation shows a waist-mounted Vive tracker arsenic good arsenic left-and-right-feet mounted Vive Trackers.

Unpausing SteamVR volition origin the Vive Trackers to vanish from the presumption wrong your headset, and you won’t spot them again unless pausing oregon utilizing an exertion designed to enactment with them, usually swapping their render exemplary for an in-game entity (for illustration a weapon oregon tennis bat).

The applicable experiments

I tried a clump of antithetic worldly including:

Attaching to bought objects
Finding immoderate games to play
Attaching to a customized object
Full Body Tracking setup utilized successful VR Chat.

Attaching to bought objects

Well, this program came unstuck rapidly as it wasn’t imaginable to bargain a Vive-tracker-compatible weapon successful the UK anymore. Both Amazon and Ebay redirected maine to sellers successful the USA, but by the clip International shipping and income taxes were added it was getting adjacent to £100, which was getting a spot costly for playing a fewer rounds of Arizona Sunshine.

Even Computer Exchange didn’t person thing 2nd hand, though their banal perpetually changes truthful I acceptable up respective banal alerts connected their website. Other brands that offered battle rifles and pistols for Vive Trackers had discontinued their products, with nary existent alternatives available.

There seemed to person been a flurry of peripheral enactment successful this abstraction during 2016-2017, pursuing the motorboat of the HTC Vive, before it went acold astir apt owed to constricted sales.

Even if each SteamVR lawsuit had bought a Tracker and peripheral successful the archetypal 2 years, that would inactive person been a precise tiny idiosyncratic basal successful the expansive strategy of hardware sales. Tooling up injection mold tooling and assembly isn’t inexpensive adjacent for a elemental weapon design.

These guys are inactive offering their weapon for $899, but with the pursuing somewhat confusing caveat (quoting nonstop words):

The connection is Vive Gun VR + tracker 1.0 version= 100% cleanable GamePlay.
Due to latest mentation vive tracker 2.0 released successful 2018, it’s not compatible with Vive weapon perfectly, that missing relation below: 1- Unusable with trackpad relation connected vive gunVR. 2- Shorter artillery beingness connected tracker 2.0 and can’t complaint by vive gunVR straight successful crippled playing.

Looking further into this, immoderate reviews online complained astir compatibility problems with aboriginal updates of SteamVR breaking thing that was ne'er fixed. I’m assuming this relates to the pogo pin inputs utilized by the antithetic brands and models of gun, but it was unclear precisely what had gone wrong.

“1.0 retired of 5 stars. Reviewed successful the United States connected 27 December 2019. Waste of $160 for the weapon and tracker. Doesn’t enactment with immoderate games.”

Some users mentioned having to usage an earlier mentation of SteamVR to get their guns to work, though this past didn’t look to enactment for Valve Index headset users who required a aboriginal physique of SteamVR.

With the comparatively precocious pricing and sizeable hassle of returning an imported weapon if it didn’t enactment properly, I didn’t discarded immoderate further clip looking into this. I had fond memories of utilizing a Vive-tracked weapon successful co-operative Arizona Sunshine astatine a VR Arcade immoderate years ago, and near it astatine that!

Anyone for Tennis?

The different enactment for an easy bought entity was “HTC’s Racket Sports Set” which they’ve stopped selling connected Amazon and lone look to merchantability straight arsenic a peculiar item. I did look astatine buying the Tennis and Ping Pong crippled “Virtual Sports” (which comes escaped with the set) but it seemed exclusive to Viveport arsenic it wasn’t disposable connected Steam.

https://www.viveport.com/apps/66bdf791-c7d1-44e3-aaf4-4bdc2ee7215a

The Racket Sports acceptable contains 2 different-sized integrative props with realistic grips, there is nary “pogo pin” transportation arsenic it doesn’t necessitate fastener input (you would usage a Vive oregon Index controller to motorboat and power the application).

The paddle and racket supply a overmuch person feeling of value and inertia compared to waving a controller astir and removing vulnerable, costly controllers from the playspace successful favour of utilizing a tougher / cheaper integrative racket and Vive Tracker.

PADDLE

Weight without Tracker: 4.9 oz.
Size: 6″ W x 10″ H x 1″ D
Connection: 1/4-inch UNC threaded equine (standard tripod mount)
Safety: Lanyard strap

RACKET

Weight without Tracker: 10.8 oz.
Size: 4.75″ W x 15.75″ H x 1.5″ D
Connection: 1/4-inch UNC threaded equine (standard tripod mount)
Safety: Lanyard strap

Looking astatine the database of Racket Sports Set compatible games, you tin spot the bulk are from the aboriginal days of the HTC Vive user launch, releasing successful 2016 and past 2017. Some person not been updated since launch, whilst others person received a mates of updates.

Thankfully I recovered each these titles disposable connected Steam for radical who don’t person Viveport access. This database shows the merchandise day and existent pricing.

Holoball, 2016, £10.99, escaped demo
Racket NX, 2018, £15.49
Selfie Tennis, 2016, £7.19
Racket Fury, 2017, £15.49
Blobby Tennis, 2016, escaped of charge
VRSquash, 2017, £14.49
First idiosyncratic Tennis, 2019, £19.49
Paddle Up, 2016, £6.99

To effort utilizing a racket crippled with 1 of my Vive Trackers, I downloaded demos of Racket NX and Blobby Tennis, past I built myself a racket for the Tracker utilizing a spare ping-pong bat. This is what happened.

I couldn’t get the Racket NX demo to enactment decently if conscionable utilizing a Vive Tracker. With nary trigger, I couldn’t really commencement the game. It besides seemed to necessitate a trigger enactment to “pull” the shot toward the bat.

It was casual to play Racket NX utilizing an Index controller and it was fun, but it wouldn’t let maine to person an progressive Index controller successful 1 manus and the Vive Tracked bat successful the other, it conscionable ignored the bat completely. I tried adjusting this occupation successful the controller settings, but nary controller settings were really available. However the afloat crippled is definite to diagnostic settings and overmuch much truthful it could beryllium worthy revisiting.

Mr. Blobby Tennis

I utilized a Valve Index controller successful my near manus to propulsion the ball, and the Vive Tracker fitted successful the bat held successful my close manus to power the tennis racket. This looked precise basal but felt truly amusive with a “blob” hostile connected the different broadside of the nett occasionally returning my unspeakable serves.

Despite maine holding a woody handled ping pong bat with a tracker attached, the in-game tennis racket didn’t consciousness excessively dissimilar owed to the consciousness of “holding a handle” alternatively of gripping a integrative question controller assemblage astatine a unusual angle.

I past decided to lengthen the grip of my “bat” to marque it consciousness much similar a tennis racquet which instantly helped things consciousness much balanced.

As soon arsenic I got utilized to utilizing my longer paddle I started to go much proficient, sometimes making a twelve returns earlier hitting 1 consecutive into the nett oregon splicing it disconnected astatine a random angle.

Despite the coagulated ping-pong bat somewhat obscuring the Vive Tracker from the 2nd basal station, I had nary issues with tracking, which was surprising. The archetypal basal presumption had wide enactment of show of the Vive Tracker connected the bat, whilst accelerated manus movements provided a affluent watercourse of IMU data, particularly acceleration.

Rays from the 2nd basal presumption would person deed immoderate sensors connected the sides of the Tracker arsenic the bat space changed during my movement. A “hollow” (cut out) bat paddle would person exposed much sensors connected the Tracker to the 2nd basal station, which is what HTC has done with their integrative racket set.

Quickly though, I realized my 3 x 3 meters playspace was a small excessively tiny and I stopped aft hitting my beforehand partition with my bat, and past my overhead airy fitting (2.5 meters up). I didn’t privation to hazard damaging the Vive Tracker, truthful I called an extremity to my Tennis crippled and enactment my bat away.

For players wanting to get into ping pong oregon tennis, there seems to beryllium a decent enactment of older titles with Tracker enactment for usage of applicable bats and rackets. Overall I thoroughly enjoyed the sensation of utilizing a tracked bat and could spot myself buying the HTC Racket Set for a much durable setup with 2 size options.

Attaching it to a customized entity – AIM Controller

After the disappointment of not being capable to bargain a weapon for playing Arizona Sunshine, I recovered a PSVR AIM Controller connected merchantability for conscionable £15 successful my section gaming store. It seemed similar an perfect clip to marque my ain customized object. The AIM controller was a precise chill peripheral built for Sony’s PSVR system. Using an AIM successful “Farpoint” was an astonishing experience, providing a tactile consciousness and overmuch improved controls with galore antithetic input options.

I downloaded a Vive Tracker render exemplary from HTC’s developer tract and bought a integer exemplary of the AIM Controller from a integer exemplary storefront for $12. These assets were imported into CAD bundle wherever they were aligned to make a hybrid of the two.

In the carnal world, I wholly stripped down the AIM controller which turned retired to be a elemental ammunition predominantly bare but stuffed with input components astatine cardinal locations. After removing 2 haptic motors, a rechargeable battery, and galore flexes, it was acceptable to accommodate the Vive Tracker.

I’d already decided to equine the tracker connected apical of the gun, to contiguous the astir disposable aspects to the basal stations for bully tracking. After rapidly manufacturing a low-profile mounting sheet from thermoplastic, I attached the tracker and took an close measurement of its presumption for usage aboriginal on.

After getting things aligned and adjusting the render exemplary record utilizing the PC, it was clip to cautiously download “the JSON” utilizing the lighthouse console. This bid downloadconfig triggers the download of the JSON to your big PC.

The updated JSON was uploaded to the Vive Tracker utilizing uploadconfig. Now erstwhile starting SteamVR Home, if pausing SteamVR, the AIM+Vive Tracker controller is seen alternatively of the archetypal Vive Tracker render model.

The adjacent measurement would beryllium to link a trigger and buttons done the pogo pins, to spot if it’s imaginable to get it afloat moving with the existent mentation of SteamVR. It should besides beryllium imaginable to acceptable 1 of the haptic motors (ERM) erstwhile triggering haptic events to supply basal rumble feedback for a crippled similar Arizona Sunshine. However, I ran retired of clip earlier this nonfiction was due, truthful I thought astir doing this decently arsenic a amusive task successful the New Year.

Full assemblage tracking setup utilized successful VR Chat

Full Body Tracking (FBT) has go indispensable for galore users of the fashionable societal media exertion “VR Chat”. Whilst different applications are available, VR Chat is the champion known and champion populated with galore users capable to prosecute utilizing desktop PC arsenic good arsenic VR headsets.

VR Chat has a thriving country with radical utilizing Avatars compatible with afloat assemblage tracking, and determination is simply a increasing assemblage of creators making and selling elaborate Avatars to the VR Chat community. There are besides thousands of escaped Avatars disposable truthful it’s rather casual to find thing you similar the look of and instrumentality an Avatar for a trial drive.

VR Chat is perfectly usable with a regular VR headset and controllers, but this lone provides “three points” of tracking (head, near hand, close hand) to thrust an Avatar.

Taking these 3 points and applying a bundle exemplary allows a calculated presumption for the avatar arms, pelvis, and little limbs known arsenic IK (inverse kinematics).

From developer Runevision: “Inverse kinematics (IK) is simply a mode to automatically cipher the associated angles of e.g. a limb oregon limb based connected wherever the end effector (typically the ft oregon hand) should be. So you could specify that the manus of a idiosyncratic should beryllium astatine immoderate circumstantial position, and IK tin past beryllium utilized to cipher the associated angles of the enarthrosis and elbow successful bid to marque the manus beryllium there.

Inverse kinematics request peculiar algorithms to “solve” the occupation of uncovering the close associated angles. This is not trivial, particularly if a limb has much than 2 segments. (A quality limb would person 2 segments portion a equine hind limb would person three.)”

More accusation astir Inverse Kinematics tin beryllium recovered present https://docs.unity3d.com/Manual/InverseKinematics.html

However, IK tends to spell wonky erstwhile users determination astir particularly the hips, starring to unusual uncomfortable sensations erstwhile the Avatar legs are going successful a antithetic absorption to the user’s ain legs. Elbows are different well-known occupation area, starring galore crippled developers to usage a “hand” oregon “glove” alternatively than presenting a afloat limb to the user.

For effectual Full Body Tracking successful SteamVR, we tin adhd a tracked hip/waist and tracked near and close feet utilizing 3 SteamVR trackers. The representation supra from Terrel Strong astatine the University of Washington was from a elaborate survey into IK and assemblage tracking.

Adding the Vive trackers provides 3 further points of tracking, providing a full of six (including HMD and 2 controllers) points that tin thrust the avatar skeleton with power connected each little limb and the waist. It is imaginable to adhd other trackers successful SteamVR, up to 9 full to further tighten up skeletal power for the fullest assemblage tracking acquisition available.

Equipment used

SteamVR-compatible headset (Valve Index)
SteamVR controllers (Valve Index)
VR susceptible PC
SteamVR relationship (free)
VR Chat (free) connected Steam
Three SteamVR Trackers (HTC Vive Tracker 3.0 with USB dongles)
USB cablegram extenders (if required)
Tracker straps (as required)

Strapping up: Waist

The Vive Trackers travel with 1/4” threaded screw mounts successful their bases, but require mounting connected straps oregon a loop truthful they tin beryllium attached to the body.

Of course, galore antithetic companies marque Vive-Tracker-compatible straps, belts, and equipment, but being abbreviated connected clip (couldn’t hold for delivery) I decided to marque my own.

The waist strap was made from a spare loop and immoderate thermoplastic I molded into a suitable mount, aft embedding a 1/4” bolt to fto maine screw the Tracker into place.

A agelong 3mm instrumentality screw was utilized arsenic a stabilizing pin to forestall the Tracker from trying to rotate nether movement. The rear of the integrative equine was faced with industrial-grade velcro, I past added a heavy foam pad to marque it precise comfy against the stomach.

The waist equine worked retired large and didn’t determination around, consciousness uncomfortable oregon origin immoderate tracking issues. The smaller and lighter Vive Tracker 3.0 helped successful this respect with little inertia erstwhile rapidly moving about.

The feeling of having a tracked pelvis truly opens up assemblage question successful VR… this was a akin revelation to utilizing the escaped Decagear exertion for Smartphones and Windows PC which added tracked hep absorption successful games similar Boneworks with large success.

The Vive Tracker takes this to the adjacent level, tracking the pelvis successful 6DoF adding a large magnitude to assemblage enactment and feelings of immersion.

Strapping up: Feet

For my feet, I decided to marque elemental footwear mounts with velcro straps and padding. The tracker was attached utilizing a 1/4” threaded fitting taken from immoderate location cinema talker partition mounts, these fittings had level integrative bottoms truthful they fitted snugly against the apical of the shoe.

Wearing shoes was champion successful presumption of stability, they fto maine strap the Trackers without being excessively tight, the mounts were unchangeable and casual to get into successful seconds. I utilized a agelong velcro strap connected each ft to wrapper implicit the built-in strap, adding different furniture of information against unwanted movement.

Despite doing immoderate unspeakable dancing and tons of random movement, the feet mounts ne'er caused immoderate occupation with the Vive Trackers behaving precise good during each my VR Chat sessions. I besides tried strapping them consecutive to my feet without shoes, and found socks were comfy but the Trackers tended to determination astir a little unless strapped truly tight, truthful preferred utilizing shoes (these person precise bladed soles truthful you tin consciousness your tether arsenic necessary).

Getting Started: Avatar time

On launching VR Chat, you take an Avatar. There are tons of antithetic escaped models disposable with afloat assemblage tracking support. I tried utilizing tons of antithetic avatars including a artifact rabbit piloting a mech suit, a red-eyed robot, a suave fox, and a tiny furry successful cyber cogwheel (which has a bugs bunny benignant look nether the visor).

Each Avatar has a “feel” to it erstwhile using FBT, and I found I truly liked utilizing the artifact rabbit successful the mech suit due to the fact that it felt close successful presumption of standard and movement, whilst the artifact rabbit driving the suit made tiny assemblage and rima movements; giving a unusual consciousness of a puppet being puppeted.

The tiny furry gave the worlds a antithetic scale, making normal-sized avatars operation implicit my rabbit. I soon noticed a batch of tiny and precise tiny Avatars successful antithetic worlds during my travel done VR Chat.

The suave fox was invited successful worlds inhabited by furries (seen successful the representation supra carrying my drinking companion, a duck, don’t ask!) and the red-eyed robot was truly precise for seeing the afloat assemblage tracking astatine enactment with its stripped-down skeleton perfect successful that respect.

Calibration – VRChat

It’s precise casual to calibrate afloat assemblage tracking successful VRChat: you conscionable unfastened the idiosyncratic paper successful game, prime “FBT Calibration” and past follow the “T” signifier (arms retired astatine 90 degrees).

You should present find your Avatar is afloat calibrated to your tracking setup. If you request to recalibrate, conscionable usage the menu. Once calibrated, you volition abruptly announcement that fine question is tracked precise accurately, including thing unprecedented… LEGS!!

“Hey Mark, we’ve got immoderate legs implicit here…”

Despite each the caller hype astir the Metawhatsit, and however we don’t person tracked legs yet successful VR… well… I moved my existent legs and my Avatar legs instantly reacted, my encephalon astir fell retired of my head with the sheer astonishment of it each 🙂

After taking disconnected my headset to recover, I checked online and it seems that “tracked legs” person been imaginable since 2017 utilizing SteamVR, truthful does possibly Meta request to double-check their data? If they privation a demonstration, they tin fto maine know: I person a “SteamVR” country wherever they tin effort retired this awesome caller exertion 😉

So the archetypal content of having legs was rather striking, though not afloat appreciated until lasting successful beforehand of a “mirror” wherever abruptly it each made an contiguous consciousness and explained wherefore radical walk each that wealth connected full-body tracking setups.

A existent regulation with single-focal magnitude headsets is VAC (vergence accommodation conflict) wherever your eyes find it hard to resoluteness precise adjacent objects successful crisp focus.

This means that looking straight down astatine your avatar’s precocious assemblage is somewhat obscured by the contented of VAC making it harder to absorption intelligibly connected your torso oregon precocious arms, but erstwhile lasting successful beforehand of the reflector the focal region of the headset is arsenic intended making things overmuch sharper.

Making infinitesimal movements that are precisely tracked successful real-time driving your avatar gives a precise beardown transportation successful the brain, feeling akin to a mild electrical shock, conscionable similar erstwhile I archetypal utilized the HTC Vive Pre successful 2016. This was experienced each clip I utilized Full Body tracking.

As galore VR enthusiasts volition sadly attest to, that electrical excitement of being successful VR during those aboriginal weeks oregon months soon fades arsenic you go accustomed to utilizing VR, making that desirable feeling of beardown beingness little regularly attainted. Some users study it becomes excessively evident they are staring astatine 2 screens strapped to their heads, contempt stereoscopic presumption and 6DoF tracking.

I thought a batch astir this whilst utilizing Fully Body Tracking, and went backmost to Skarredghost’s caller interview with the legendary Jeremy Bailenson:

“There’s a gag I archer astatine cocktail parties, and it’s not truly a gag due to the fact that it’s not comic astatine all, but if you’re going to inquire me, what are the 5 astir important features that origin beingness successful VR? My reply for you is going to beryllium tracking, tracking, tracking, tracking, tracking. I’ve thing against resolution… it’s ever bully to spot a precocious res image, and, of course, tract of presumption is important, but if you’re going to animate presence, the happening that’s astir important is debased latency, precocious framework rate, precocious accuracy of tracking (which is truly important)”

I’ve work galore comments from radical inactive happily utilizing the archetypal HTC Vive strategy for VR Chat, successful their experience having precise close Fully Body Tracking is overmuch much important than having a higher solution headset. It’s besides casual to prime up utilized Vives astatine debased prices, providing an inexpensive way to FBT (Full Body Tracking) for cash-strapped enthusiasts. Just beryllium alert that basal presumption 1.0 and 2.0 exertion doesn’t ever mix.

To show FBT from my ain perspective, I took my “toy rabbit successful the mech suit” avatar for a rotation and made immoderate antithetic poses successful beforehand of an HQ reflector successful VR Chat. At the aforesaid time, photographs were taken of what I was doing astatine precisely the aforesaid clip successful the existent satellite (these person been flipped horizontally to lucifer the reflector representation from VR Chat).

Subtle assemblage connection seems to construe consecutive done the avatar which is thrilling stuff. The usage of afloat assemblage tracking with sub-millimeter precision truly helps with immersion and experiencing beardown feelings of beingness again.

Being capable to prevarication down, basal up, rotation over, karate kick, basal connected 1 leg, and creation about felt truly liberating contempt the tether. Dancing successful a reflector alongside different FBT users was truly vivid with each the subtle assemblage movements doing a precise convincing occupation connected my subconscious lizard brain.

As soon arsenic you commencement utilizing FBT regularly you commencement to announcement different idiosyncratic Avatars and who has FBT oregon who is utilizing a modular VR strategy with 3 points of tracking. The quality successful the assemblage connection is nighttime and day, with the FBT users precise lifelike whilst modular users look somewhat stiff and unnatural. No judgement oregon elitism here, conscionable an observation. I tried utilizing VR Chat a mates of times without the Vive Trackers and thing was decidedly missing…

Pricing

HTC Vive Tracker 3.0 are disposable for a recommended retail terms of £129 successful the UK from antithetic electronics retailers oregon from HTC straight astatine https://www.vive.com with escaped shipping.

For immoderate reason, they are recovered to beryllium a small little costly done HTC’s Amazon store astatine £127.50 including escaped shipping and escaped returns.

Alternative SteamVR tracker-style devices are besides disposable from Tundra Labs and Manus (aimed astatine the nonrecreational market).

Conclusions

The 2nd portion of this nonfiction was a batch of fun, and a learning acquisition astir the powerfulness of afloat assemblage tracking to dramatically summation immersion starring to stronger feelings of beingness connected a repeatable basis, which for a semipermanent PCVR idiosyncratic was a revelation. I’m precocious to the FBT enactment but amended precocious than never, and the Vive Tracker 3.0 is simply a utile betterment connected the erstwhile generation, truthful precise casual to recommend. The bundle connected the SteamVR broadside seems to person matured with bully Tracker enactment making it casual to acceptable up and manage. I had nary issues during weeks of usage nary substance however I moved oregon what I did.

I went into this expecting to person tons of amusive gathering tracked objects and exploring antithetic games, but truthfully the revelation of FBT meant much clip was spent successful VR Chat wherever it was casual to enactment FBT to bully use. Other applications are available, truthful look for FBT enactment erstwhile checking retired caller software.

There are sports games that volition enactment with the Vive Racket Sports set, and if you are into tennis, ping-pong, oregon akin sports then it should beryllium good worthy the acquisition of a Vive Tracker and a suitable bat. Whether guns presently enactment I cannot corroborate nor deny, but I’ll effort to physique retired my tracked AIM weapon successful the New Year, truthful I conjecture I’ll find retired then.

As I mentioned successful my archetypal article, the usage of FBT for applications similar VR Chat seems to beryllium driving steadfast income of Vive Tracker (I met a batch of FBT users) whilst peripherals are bladed connected the crushed and not supported successful galore (if any) modern games.

What astir the costs?

It’s not a concealed that it’s comparatively costly to acceptable up afloat assemblage tracking, if doing it decently with SteamVR and tracker-style devices.

You person to commencement with a SteamVR strategy similar Valve Index (£920) oregon Vive Pro (currently £719 connected sale), past adhd 3 Vive Trackers (£387 with shipping) and immoderate Tracker straps (typically £40-70 for set), and of people a VR susceptible PC.

Are determination alternatives?

For radical utilizing VR Systems that are not SteamVR autochthonal (like Vive oregon Index) it’s imaginable to adhd basal stations and SteamVR controllers and past combine the Quest/Pico/WMR and SteamVR playspaces utilizing an exertion similar Open VR Space Calibrator, which you tin find astatine this link: https://github.com/pushrax/OpenVR-SpaceCalibrator. It is described by the developers as:

“This helps you usage tracked VR devices from 1 institution with immoderate other. It aligns aggregate tracking systems with a speedy calibration step. It whitethorn not enactment for your setup, but determination are galore cases that enactment to a degree, and immoderate enactment precise well.”

However, results whitethorn vary, with immoderate users reporting it’s astir unusable whilst others notation it works but regular recalibration is required arsenic the 2 tracking systems thin to drift apart. For this reason, immoderate users volition swap to a SteamVR headset (even an aged Vive) to supply a reliable and hassle-free Fully Body Tracking solution.

There are different full-body tracking systems connected the market, utilizing aggregate IMU, outer cameras, magnetic fields, oregon different tracking technology. They don’t thin to beryllium precise accurate, oregon endure from drift, but bash supply immoderate entree to assemblage tracking astatine a much affordable terms than going the basal presumption route. Truly a lawsuit of “you get what you wage for”…

However, arsenic esteemed boffin Jeremy Bailenson said, “what are the 5 astir important features that origin beingness successful VR? My reply for you is going to beryllium tracking, tracking, tracking, tracking, tracking.”.

From my acquisition with the HTC Vive Tracker 3.0 during these months, they volition surely supply what you request for FBT and sports gaming, providing that all-important feeling of presence. Highly recommended!

Thanks! Big acknowledgment to HTC for providing the Vive Trackers and answering each my questions, acknowledgment to Tony Skarredghost for hosting my article, and most of each acknowledgment to you the reader.

(Header representation by Rob Cole)

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