Categories
ergonomics

VR Cover’s ‘Valve Index face gasket’ and ‘rear cover’ reviews

Originally posted by SkarredGhost, edited to correct my original spelling mistakes.


Introduction by Tony of SkarredGhost

The VR ergonomics expert Rob Cole of immersivecomputing.org has tried for us the VR Cover headset covers for the Valve Index, and had reviewed it for us. I’m very glad to host in this blog his professional impressions on this VR accessory, that it’s very informative for all the VR community. Considering that very soon there will be the launch of Half-Life: Alyx, all people owning a Valve Index are for sure interested in anything that can improve the comfort of their VR headset.”


VR Cover: Valve Index Interface & Foam Replacement Basic Set

valve index face gaskets
Playing with many different Valve Index face gaskets

The face gasket conundrum

Nine months after launch, replacement “face gaskets” for the Valve Index remain somewhat thin on the ground.

Valve’s official face gasket is often out of stock, and was only released in one width which may not be suitable for everyone.

Shipping Index with a single gasket was odd, considering Valve’s earlier collaboration with HTC which had seen the Vive shipping with both narrow and wide face gaskets in the box. 

Later I learned from Steam user BOLL that Index was originally listed in early April 2019 as coming with “2 Face Gaskets (narrow and wide)“.

By the end of April he had noticed the webpage had been edited to remove any mention of narrow and wide, leaving just “Face gasket”.

I’ve asked Steam support several times since launch about an official wide face gasket, but I always get the same reply

Steam support does not have any information on when or if a new gasket will be made available.

One of the moderators on the valve index subreddit said they had learned that the Index development kits had shipped to SteamVR developers with both width gaskets in the box, mirroring BOLL’s earlier findings. 

Physical evidence of a large Index face gasket recently emerged on Reddit after someone was mistakenly sent one of the “L” gaskets by Steam Support. As seen in the photo below, it has the old “clip in” pre-production mounting tabs, Valve then switching to magnets for the production gasket.

Perhaps this means some tooling or 3D printing files exist for this L model somewhere at Valve or their manufacturing partner in China, giving me hope that it could be released in the future!

The wide face gasket

As my previous article for SkarredGhost “Valve Index : A Good Fit?” mentioned, I couldn’t use my Index with the original Valve face gasket as it simply did not fit, it was too narrow for my face.

As a former Vive owner who always used the wide face gasket, this was puzzling as being a “sample-sized” person (medium everything and 63.5mm IPD). I am no huge-headed outlier requiring an oversized gasket, just a regular-sized person, if there is such a thing.

Perhaps it’s not well known that the wide Vive gasket was really a “regular” fit, with the narrow being for people with narrower faces; some Vive owners with larger heads had to build their own extra-large gaskets. This is why the wide gasket was fitted to the Vive headset in the factory and the narrow came as a spare inside the box. 

valve index out of the box
Valve Index, just taken out of the box

A temporary solution was provided for my Index gasket problem by 3D printing a stretched version of Valve’s plastic face gasket base design, that they had released as part of a big Index data dump into the public domain. Big thanks to Valve and to Anonymous Hermit for modifying the face gasket!

After receiving a 3D printed base from Ninja Prototype in China, I had stuck Velcro and magnets into place, using the Velcro to attach aftermarket Vive PU face cushions. As the Vive cushions were smaller than Index’s wider eye box I ended up cutting them to fit, to maximize the field of view. 

This was less than ideal as it had left several unsealed edges where the cushion was cut, which degraded over time from heat, moisture (sweat) and physical contact (abrasion) against the face from using and donning/doffing the headset.

It also caused mild skin irritation during longer or more active sessions with the PU cushions trapping heat and moisture against the skin; I experimented with some spare fabric from an Index face gasket I had stripped, which certainly added some skin comfort.

valve index wide face gasket
Adding some spare Index fabric onto the PU to increase the comfort

After going through a number of cut-up cushions since last year, I was excited to hear about the first commercially available Index Face Gasket from industry stalwarts “VR Cover”.

VR Cover to the rescue

VR Cover has been making face gaskets, face cushions and other facially related parts since the first consumer headsets launched in 2016. Tony @ SkarredGhost put me in touch with the nice people at VR Cover who sent a sample I could test (thanks Sharon!)

vr cover valve index
Box sent by VR Cover

The package arrived in a very neat plastic container, consisting of:

  • 1 x Facial Interface (plastic gasket base)
  • 1 x PU Leather Memory Foam Replacement (Standard) i.e. thin
  • 1 x PU Leather Memory Foam Replacement (Comfort) i.e. thick
  • 2 x side wedges
vr cover cushions
Cushions provided by VR Cover

This was an impressive set of parts, well finished especially the plastic base with its own Velcro facing and magnets.

The first thing I did, of course, was to compare the VR Cover plastic base with my own 3D printed wide base and an original Valve gasket, and this is where I noticed a key difference; the VR Cover plastic base was identical in radius to the original Valve face gasket.

valve index 3 face gaskets
Top to bottom: valve Index face gasket, 3D printed custom wide face gasket, VR Cover Valve Index face gasket

Looking closely, I realized VR Cover had created two fitting options on a single width plastic base by supplying thin and thick versions of their PU cushions.

Using the “thick” cushion gave me an identical fit to the original Valve face gasket, albeit with a different material. I tried installing this option but as with the Valve original, I had a noticeable gap between my forehead and the cushion which prevented me getting my face forward enough to fit the headset correctly.

I also tried the side wedges but could not get my face anywhere close to the front of the face cushion!

VR cover side wedge
Trying with side wedges, but with no luck

Using the “thin” cushion gave a wider fit than the original Valve face gasket, but still not as wide a fit, as my 3D printed setup.

Width is better talked of as radius, or circumference, in my case a 59cm head which is the upper end of “medium” in a bicycle helmet or baseball cap – the thin cushion and VR Cover plastic base wasn’t an ideal match, but certainly closer to my measurements than the Valve original face gasket. 

Unfortunately, I soon found that using the “thin” cushion led to physical discomfort and red marks on my forehead, as I could clearly feel the plastic base pressing though the thin cushion which after 30-45 minutes of use left my face feeling a little sore.

This was not unique to the VR Cover’s thin cushion by any means, Index is a relatively heavy headset which means extra cushioning in the face gasket helps to spread the headset weight and headset clamping force across the available areas of the head and face. To confirm, last year I had experimented with using thin aftermarket Vive cushions with my 3D printed base but had soon switched back to slightly thicker cushions to increase session comfort

Of course, there was nothing stopping me from trying VR Cover’s face cushions in my 3D printed wide base, these fit well and let me experiment with the thin and thick cushions.

The thick cushion worked well at first, providing extra comfort to isolate my face from the headset weight and clamping force.

Installing the VR Cover inside the 3D-printed plastic gasket base

The thin cushion also worked to bring my face as far forward into the display as possible. However, despite the increased radius of my 3D printed base, the physical weight of the Index headset soon made its presence known through the thin cushion, again leaving me feeling a little sore after an hour of use.

Using VR Cover’s thick cushion with my 3D printed base gave a more positive outcome than using their thin cushion with the VR Cover plastic base, so I carried on using the thick cushion for a while.

However, after perhaps two weeks of regular use, I started to notice the weight of the Index headset again and realized the foam inside the thick face cushion was slowly flattening out (thinning) reducing my comfort. After another two weeks, my thick cushion did not look much thicker than the thin cushion (which I had hardly used) and I found it a little uncomfortable apart from short sessions with less movement.

The PU issue

Something else that has to be mentioned, and it’s not specific to VR Cover’s Index face cushion, is the biological incompatibility of PU as a facial interface material when you consider the skin’s requirement to breathe (release heat and sweat).

There is little evidence that the PU material itself causes a reaction as fully reacted polyurethane polymer is chemically inert.

From the PU Manufacturers Association: “Skin contact with some polyurethane products may result in skin sensitization”, but also “There are no applicable exposure limits for cured polyurethane materials”

There is very little information on the use of PU as a skin contact layer, I found this from the US National libracy of medicine, which concluded that PU was more effective than silicone for scar treatment:

Efficacy of a polyurethane dressing versus a soft silicone sheet on hypertrophic scars.

The polyurethane dressing demonstrated a significantly more pronounced reduction in severity of these clinical signs after four and eight weeks of treatment and was better tolerated than the silicone sheet.

So whilst PU itself is generally not an irritant, it can act as a “dam” to prevent the skin from breathing in areas directly in contact with the gasket – think of it as being a waterproof layer between your skin and the outside world, this then stops the skin functioning properly in that area.

Away from medical trials, back in the VR world, the PU cushions were doing what they’ve always done for me which was the causing localized skin irritation, leaving my forehead sore after a session with a big red mark, combined with the weight of the headset pressing through the cushion. Longer-term there is a tendency for these marks to develop into spots or blemishes where the skin is repeatedly irritated.

vr headsets red mark face
Red marks left on the face of the user

PU has its advantages for VR facial interfaces, as it doesn’t absorb moisture, so it’s easy to clean which makes it ideal for sharing headsets or use at public events where hygiene is critical and users are only doing short sessions (i.e. VR demo at a shopping mall). 

It also has an adhesive property in that it sticks to the skin when wet, making the headset “stick” in place better at the expense of making it difficult to reposition. One practical example of this is if you snag the tether and yank the headset out of position, it’s then much harder to reposition on the face with a damp PU cushion.

For a solo user at home, wearing a device like the Valve Index which is designed for long term comfort, the PU cushion started irritating my skin making my Index less comfortable, negating the possibility of longer sessions with adequate comfort.

The materials that Valve used on the Index face gasket were specifically used to increase user comfort to support long sessions, and this was my realization after months of using different PU cushions and fabric covers.

Of course, before receiving the VR Cover sample, I was using PU cushions in my modified 3D printed base, but these had a perforated surface, and had been cut into three pieces providing some extra breathability. The VR Cover PU cushions were fully sealed, with no surface relief, effectively trapping whatever local heat and sweat my head produced.

Once again I must stress the issues of PU cushions are not unique to this VR Cover product, depending on how active your session is, your fitness level, room temperature and so on….will all have an effect on how much of an issue using PU is?

Solution to the PU issue?

I’ve given some feedback to the team at VR Cover, to see if there is an alternative material – this is not an easy task as the material needs to be biologically compatible whilst being durable and easy to clean! 

As many Valve Index owners found out with the original Index Face Gasket, it soaks up sweat very quickly, becoming moisture-laden with a tendency for bacteria to build up inside the foam core leading to a less than pleasant experience.  Whilst it was possible to wash under cold water and air dry, this didn’t deep cleanse the cushion and repeated washing started to create ripples in the fabric surface.

Another aspect of PU that has to be mentioned, as it was commonly cited an issue on the HTC Vive when used with aftermarket PU cushions, is the build-up of heat and moisture inside the headset.

One function provided by the fabric cushions on the Vive and Index is to wick away moisture from the face and store it inside the cushion, effectively protecting the electronics inside the headset. I noticed very quickly when using PU cushions that my headset got wet inside, at the top where the lens assembly is located.

valve index sweat pu
Valve Index with sweat caused by PU cushions

In the short term, this meant more frequent removal of the headset and cleaning of the lenses as they become covered in sweat smearing the surface and reducing clarity.

In the long term, this may cause problems, as some Vive owners found when using aftermarket face cushions leading to corrosion damage to the PCB inside the headset, something that rarely affected people using the original fabric faced cushions.

Whether this can damage the Valve Index is unknown, the Vive reportedly lacked any internal waterproofing; I’ve seen some “tear down” shots of the Index where its PCB appears to have a waterproof coating but I can’t confirm this.

The ripple effect

Another big improvement could be a “pre-curved” cushion to eliminate the ripples that are created by fitting a flat-cut cushion to a curved plastic base. This is caused by the inside face (plastic base side) and outside face (face side) being the same distance/length.

As the cushion is fitted into the plastic base the inside face is stretched whilst the outside face is compressed causing the ripples seen in my image. These ripples can be felt across the forehead and may be partly responsible for the discomfort felt during longer sessions.

Ripples cushion valve index vr cover
Ripples on the VR Cover cushion

Once again, this is not unique to VR Cover, and is seen in many other VR face cushions. The big advantage of a pre-curved face cushion is the absence of ripples or material bunching up as the pre-curve naturally matches the radius of the plastic base on both front and rear cushion faces. 

The original Valve Index face cushion and Oculus Rift CV1 face cushion are both pre-curved designs with no ripples appearing in the surface until well worn.

Conclusion?

Overall the VR Cover set has a good design concept as I like the modular approach, and of course bringing an alternative Face Gasket for the Valve Index to the market is very welcome.

For people who want a same width replacement for the Valve Index Face Gasket and cannot buy one from Valve due to stock levels, it will solve that problem. 

For those who cannot 3D print a plastic base, or don’t feel confident building their own, VR Cover’s plastic base provides an instant solution with two cushions to choose from.   

For people requiring the wider face gasket (without 3D printing) it can offer a solution but your fit and comfort will depend on your craniofacial shape, and whether you can tolerate the “thin” cushion which I had to use to make it wider. 

However, it’s still not as wide fitting as the 3D printed option and I did find it uncomfortable for longer with the PU material causing a skin irritation; as said before, not unique to VR Cover but just the use of PU as a skin contact layer.

My final conclusion is that choice is always good so VR Cover needs to be congratulated for bringing this to market. I’m sure with further developments by the VR Cover team this product can offer more fitting and comfort options for Index owners. 

In an ideal world I’d like to see VR Cover offer 2 versions of their Index kit:

  • Regular plastic base (as tested here)
  • Wider plastic base

Each base could be supplied with 2 pre-curved face cushions (1 for use, 1 for spare)

I’d recommend using a medium thickness cushion of a higher densitybreathable foam core and skin-compatible surface material.

Valve Index Head Strap Cover

Later on, I received VR Cover’s new “Valve Index head strap cover”.

VR Cover valve index rear cushion
Valve Index Head Strap Cover

In their own words:

Experience a fresher, cleaner headset when you add our hygienic 100% cotton cover to your Valve Index. Our absorbent cotton accessory wraps onto the strap and quickly soaks up sweat from the back of your head to leave you feeling more comfortable.

The set includes:

  • 2 x Valve Index Head Strap Cover

A concern for a number of Index covers was the non-removable rear cushion inside the headset harness. Despite using the same anti-microbial fabric as the original Valve index face gaskets, it was obvious that over time this could become dirty, stained or unhygienic.

Valve Index rear cushion
Valve Index rear cushion

Of course, I’ve tried to remove the head strap’s rear cushion on my Index months ago in an attempt to drill a hole through the headband plastic to modify the tether cable routing, but had stopped after finding it was retained using what looked like one-time “snap fit” plastic clips.

After levering an area of the cushion’s plastic backing with a flat blade screwdriver it felt like the clips might snap, so I left it in place. This presented a problem as there was no way to replace the fabric facing of the rear pad; over time this could take on moisture, bacteria, dirt and become worn or compressed from regular use. Replacing the rear harness was not possible at a consumer level, even if spares were available. 

Upon opening VR Cover’s Index Head strap cover kit, I was a little confused by the instructions until I realized both covers were inside out. Turning them the right way around helped, but the instructions still proved a little confusing so I tried fitting it myself to figure out exactly where the straps and Velcro were supposed to go. It’s great that they supplied two, so you have a spare for yourself, or can run two so you have a spare for guests to use (this works well combined with a spare face gasket). 

valve index rear covers
Valve Index rear covers plus instructions

Eventually, I got the cover fitted to my Index, and placed it on my head. Immediately I noticed the harness was now a little too tight as adding the cover had slightly reduced the circumference so I backed off the rear knob adjuster 3 clicks.

Valve Index rear cover fitted
Rear cover fitted to the headset

The most interesting aspect was discovering that the fabric cover firmly gripped the rear of my head (mainly the occipital bone). This added a welcome degree of stability to the head strap, reducing front end (eye block) movement of the VR headset. Not something I was expecting but a very welcome surprise.

It also felt a little softer and more comfortable across the rear of the head strap / harness, I didn’t notice any difference in heat or sweat compared to using the “naked” Index head strap, despite energetic sessions in Beat Saber and Pistol Whip.

valve index rear cushion cover
Rob Cole wearing the headset with the rear cushion cover

As I’ve only been using it a few months, I cannot comment on long term durability except to say it’s not showing any wear, and if it does wear then it’s done in job in protecting your Index. It’s also great value, coming with two covers, perhaps fitting the cover on day one of your Index ownership will help your Index maintain its own value rather than degrading as many VR headset tend to over time.

The only improvement I could think of was to the instructions, it might have been me not understanding them but that in itself is the “acid test”: can they be understood very quickly and easily? The VR Cover head strap cover itself thankfully suffers no such problem, it’s highly recommended by me!

Thanks to VR Cover for the test samples and of course thanks to Tony @ SkarredGhost for the hookup.

And thanks to you for reading!

Categories
ergonomics

Controllers, controllers, controllers…

“Many different controllers, they each have their own uses, their own form factors and their own quirks…no judgement here, I’ve enjoyed using all of them.”

Rob Cole, immersivecomputing.org
Google Daydream – 3DoF
Oculus Go – 3DoF
Vive Focus – 3DoF
Samsung GearVR – 3DoF
HTC Vive Wand with Hyperkin cover – 6DoF
Sony PS4 dual shock (PSVR)
Playseat Gran Turismo (PSVR)
Force feedback wheel (PCVR system)
Oculus CV1 Touch – 6DoF
Paragliding toggles (PCVR system)
HTC Vive trackers and force feedback wheel (PCVR system)
HTC Vive wands – 6DoF
Optitrack blaster prop @ The Void – 6DoF
AIM controller (PSVR) – 6DoF
Lenovo Explorer (Microsoft WMR) – 6DoF
Oculus Touch (insight tracking) – 6DoF
Valve Index controller (Knuckles) – 6DoF
HTC Vive 2.0 tracking puck – 6DoF
FANATEC motion simulator (Samsung)
Xbox controller, Steam controller, Valve Index controllers and Logitech Gaming keyboard and mouse
Driving rig (PCVR system)
Microsoft Hololens hand tracking
Leap Motion hand tracking @ The Void
Steam controller
Xbox controller with wireless receiver in Index Frunk (PCVR)
Magic Leap Control – 6DoF
Valve Index controller (with Palm Boosters) – 6DoF
TG0 Etee Dev kit (3DoF)

Thanks for reading! Rob Cole

Categories
ergonomics

Valve Index : Ear ergonomics

Originally published by Skarredghost in December 2019. Edited to correct my original spelling mistakes and some images updated. All images copyright of immersivecomputing.org unless otherwise indicated.


Introduction by Tony @ SkarredGhost

“Today I publish the third and last part of the interesting deep dive on the Valve Index comfort by Rob Cole. If you lost the other two parts, here you are the link to the first one, and here the link to the second one. He also wrote a very interesting article on VR ergonomics some months ago.

Rob first tried VR in 1991 and has become an enthusiast of the tech ever since. Because of his background in industrial design, he has always had a strong interest in the design and the ergonomics of the VR headsets. At Immersive Computing (see his Instagram account) he carries on this interest, exploring the technology always starting from the human perspective, putting the human at the center of his experiments and analysis. This post is the result of such kind of experimentations on the Valve Index headset. I hope you will enjoy it!”


For this third article, we will concentrate on the Index Ear Speakers.

The first article has already covered my experiments with the Index Facial Interface, whilst the second article looked in depth at the Index controllers.

The Index Ear Speakers

When I first saw the “leaked” images of Valve’s new VR headset it appeared to have headphones on adjustable arms, similar to the Oculus Rift CV1.

leaked image valve index
Leaked images of the Valve Index (image??)

Though looking closer, the “headphones” had metal mesh on both sides but no ear cushioning. Each speaker was canted slightly inwards to face the angle of the ear, they were attached with a sliding adjustment arm; perhaps these were “off-ear” (extra-aural) loudspeakers instead of the on-ear headphones of the Rift.

I wasn’t going to learn any more by looking at the pictures though it got me thinking about why audio is so important, so I read what some experts had to say.

If you talk to any director, they’ll say music is fifty percent of the movie.

Hans Zimmer  (Film score composer)

Sound is important because it can tell us about character, place, and time. It’s important because it informs us and moves us in ways visuals can’t, and because certain combinations of sound and visuals can evoke what neither can do alone. It’s also potentially important because it can help to determine what we see. But why be shy? Visuals are sometimes important because they help to determine what we HEAR. 

Randy Thom (Director, Skywalker Sound)

Sound is what truly convinces the mind is in a place; in other words, ‘hearing is believing.’

Jesse Schell (Video game designer)

There was lots of information available on the importance of sound in cinema and video production including video gaming and virtual reality. Many studies reported a close relationship between the video and audio channels with a significant cross-modal influence of audio on visual quality, and vice versa.

As new headsets become available with higher quality visual displays, it wouldn’t be a stretch to posit that a high-quality display should be matched with high-quality audio (and high-quality haptics), to provide sensory consistency in Virtual Reality.

Surely high-quality audio is just for audiophiles?

Try listening to your favourite music using high-quality audio equipment to experience a clear separation of instruments and the reveal of subtle, hidden details; you may notice things you’ve never heard before in your favourite songs.

Whilst I don’t see myself as an “audiophile” I am someone who appreciates good quality sound. I’ve always bought quality audio headphones and have owned a number of Hi-Fi audio separates and home cinema systems.

It’s enjoyable to have high-quality audio when listening to music or watching movies but I’ve come to understand over the past three years that high-quality audio is even more important for virtual reality to help convince the user they are “present”, as Jessie Schell said “..hearing is believing”.

So why not just use audio headphones or earbuds then?

For VR headsets without their own headphones or with ineffective audio but boasting an audio socket; audio headphones or earbuds may seem like an ideal solution, but for 2 important concerns.

  1. FrictionOnboarding is further complicated by fitting headphones or earbuds over, under or into a VR headset. Putting on and taking off isn’t much fun, especially with unstable VR applications causing system crashes, requiring more frequent removal and refitting. The inevitable tangle of cables and unwanted interactions between head straps cause the loss of visual sweet spot, headphones that move off ears, earbuds that get yanked out, straps that need re-adjusting. All of this is irritating causing “friction”.
headphones vr headset
A tangle of straps and wires, there seems to be someone in there somewhere??
  • 2. Sound quality. It depends on the headphones. Beats Audio vs. Sennheiser vs. Beyerdynamic have a very different sound. Different models from the same manufacturer have a different sound.  Different headphones designs also have different sound quality affecting the overall quality of your VR experience. Open back, Closed back, Noise-cancelling, On-ear headphones, Over-ear headphones, earbuds… there is a lot of choice, but many are optimised for music rather than VR.
vr  headsets audio
There are many different headsets and many different headphones, the audio possibilities are endless, who knows how each will sound differently?

Someone who knows a lot more about sound than I ever will, Emily Ridgway at Valve, has commented sound in VR this way:

The tonal sound quality of some headphones can interfere with the subtle frequency colorations of binaural simulations. For example, headphones, where mid-high frequencies are either exaggerated or muffled, will most likely interfere with the subtleties of HRTF filters, resulting in a poor sense of directional sound in games and VR.

In contrast, onboard audio reduces fitting friction and eliminates any awkward moments involving cables, as well as providing developers with the benefit of a known audio system for application development on that VR headset.

Whilst I did find many quality headphones from audio brands worked well for VR in terms of pure audio; the good quality sound and reduced friction of the Rift CV1’s built-in audio system was welcome – a real “quality of life” improvement, no doubt.

Having used many headsets with both built-in audio and with many different models of audio headphones, it was very encouraging to see Valve paying particular attention on their new headset with those built-in speakers, or whatever the ear pods actually were.

So its called “Index”, what about those ear pods?

So after Valve released the first public information we found out the headset was called “Index” and the ear pods were actually “BMR Ear Speakers”. Later on, this reason was given by Valve for not choosing a headphone-based design like those used on the Vive DAS or Rift CV1:

Delivering sound directly into the ear canal bypasses the natural listening process caused by ear and head interacting with real sound waves. Listeners miss out on the tonal sound signature created by the ears, head and personal geometry. This can result in sound appearing as though it’s imagined, or it’s coming from inside one’s head, even if the audio content is highly spatial and physically simulated

Valve

Some smart thinking going on there at Valve no doubt, but what exactly is “BMR”?

Balanced Mode Radiator technology

BMR stands for “Balanced Mode Radiator”, a different design of speaker to the conventional “pistonic” drivers you find inside conventional headphones and loudspeakers.

An early proponent of BMR in the audio space were British company Cambridge Audio, who explain it like this:

BMR, or Balanced Mode Radiator, is a new and patented technology that brings a number of exceptional advantages to audio reproduction. Traditional speakers separate treble and mid-range speakers in order to provide good sound. BMR technology on the other hand, helps create a full-range sound by providing treble, mid-range and even a little bass all in one neat little package!

how does bmr work
(Image by Cambridge Audio)

Even from smaller more compact speakers, you can hear the difference for yourself by listening . Thanks to BMR, you get a wide range of frequency for such a deceptively small speaker.

Cambridge Audio

Valve’s BMR ear speakers were developed in partnership with Tectonic who already made a wide range of BMR speakers for different applications; but as far as I’m aware this is the first time that BMR technology has been used in a VR headset.

The image below shows another Tectonic BMR with a larger diameter speaker and driver which is used for manufacturing high quality home cinema soundbars. 

tectonic bmr
Tectonic BMR speaker (Image by Tectonic)

Valve then released their “Deep Dive” series with one blog post concentrating on the ear speaker project, showing all the different audio systems Valve used during their prototyping stage:

By using BMR drivers, we are able to ensure consistent sound quality, without coloration, even if the speakers are slightly mispositioned on the side of the head. This is due to the unique way that BMRs radiate sound. At low frequencies they behave like traditional speakers. The electrical signal comes in, and the entire diaphragm (front part of the speaker) moves back and forth tracing the shape of the signal. However, the real magic happens at higher frequencies.

When the wavelength of the bending waves travelling through the diaphragm is similar to the size of the diaphragm, traditional drivers start to go into ‘break-up’ modes which cause the diaphragm to bend and ripple, creating very sharp peaks and dips in the frequency response that, in addition to sounding bad, are very placement sensitive. BMRs are designed to exploit the natural behavior of the diaphragm, balancing the vibrations from different areas through optimized material selection, mass loading and extensive design simulation.

Valve Corporation
Very clear but a little quiet

When I received my Valve Index at launch on 28th June I was very interested to try out the “BMR ear speakers” and compare them to my audio headphones and the on-board headphones I’d used on the Vive DAS, Vive Pro and Rift CV1.

The first thing I noticed was their range of adjustment; the ear speakers are mounted on pivoting arms with a sliding adjustment mechanism which allows:

valve index speakers adjustments
Allowed vertical movement of Valve Index speakers (red line indicates range)
  • Vertical movement (speaker drops below the ear or rises above the ear), the image shows the maximum raise and maximum drop that is possible using the sliding mechanism, the gap difference between the red bars showing the range of vertical adjustment.
Allowed rotational range of movement of the Valve Index speakers
Allowed rotational range of movement of the Valve Index speakers
  • Rotational movement (pivots around mount relative to ear), the image shows the full range from full forward to the full rear. It’s typically used in the orientation shown in the image with the full rear rotation being used when fitting the headset (so speakers are clear of ears) and for storing the headset so it is not resting on the ear speakers.

The combination of vertical (drop and raise) and rotational (pivoting) adjustment enables the user to place the ear speaker across a wide area which should cater for many different users with ears in different places.

valve index speaker fitting
Fixed distance of the ear speaker of the Valve Index to the ear
  • Depth adjustment (closer to ear or further from ear) this was a fixed distance as indicated by the red bars in the image, it’s not adjustable apart from a small bending action at the top of the speaker arm which doesn’t translate to any meaningful adjustment as it just springs back when you let it go.

I was surprised it was not adjustable but figured the BMR ear speakers needed to be at a set distance or they didn’t want people pushing them against their ears?

Powering up the Index, I adjusted the ear speakers to find their “sweet spot” (they do have one) and tried some different VR applications which quickly demonstrated that the ear speakers had the clear definition and good separation typical of a high-quality driver.

However, the bass was a bit lacking and overall the audio was a little too quiet.  I wondered if I’d missed a setting in Windows 10 or Steam VR as the audio volume sliders were set at 100% but it was still too quiet compared to other audio systems I’ve used for VR.

Being an off-ear, “open” audio system with an air gap between the speakers and my ears, it also needed an increase in volume to block out background noise.

Looking around the VR forums on the internet, I found other Index owners with similar questions asking about raising volume levels, with several people asking if there was something wrong with their BMR ear speakers and they needed replacing them. Maybe the ear speakers needed more power than headphones?

Adjusting Windows sound equalizer and various settings in SteamVR including checking the box marked “Vive audio gain” (popular suggestion on Reddit) made no volume differences. I tried moving the BMR speakers to make sure the “sweet spot” was aligned as best possible with my ears, but without any real difference as they simply weren’t loud enough. 

The background noise issue

With the BMR speakers seemingly underpowered, initially, I was not impressed with Index’s audio: background noise was breaking immersion as an unwelcome but everpresent audio guest.

The ear speakers were not loud enough to smother my ears in VR sound as I could still hear the noise of my PC (even on silent mode) and noises of the city such as traffic, sirens and the occasional aircraft.

I should also mention the “2.0 Base stations” that are used for SteamVR, these have a slight but noticeable high pitched whine when running, it was always there in the background, a bit distracting.

Something had to be done to block the noise, so it was time to try some headphones; I quickly removed the BMR speakers which was easily done with a Torx T6 driver.

valve index bmr speakers
BMR speakers, removed from the headset

Removing the BMR ear speakers revealed the mounting which has a keyed shape and 2 electrical contacts for the “pogo pins” used on the ear speaker. As the T6 fitting is tightened against the inside of the headstrap arm, it locks the ear speaker and headstrap’s keyed socket shapes together, creating a firm perch for the ear speaker to hang off and rotate around. 

Index speaker mount
Valve Index speaker mount showing pogo pin design for audio channels
Headphones as a temporary solution

The Index has a hidden audio output tucked away behind the magnetically attached face gasket. As this was just after launch I was still using the standard (narrow) face gasket – which had just enough clearance for the 3.5mm jack plug of my Sennheiser audio headphones.

Several pairs of headphones I tried would not fit as the audio socket is deep requiring a long jack plug, but there is limited clearance for this behind the plastic base of the face gasket, causing a sharp bend in the cable or lifting the face gasket base off the headset mounts.

Since headphone leads with long molded strain relief sleeves and thicker cables could not accommodate such a tight bend, I purchased a shorter and thinner audio lead (for smartphones) for my Logitech headphones so I could use them with the Index.

Index with Logitech headphones
Valve Index with Logitech G series headphones

Removing the BMR ear speakers and replacing them with headphones definitely helped as they have a closed, over-ear design which shielded my ears from much of the background noise. However, plugging my headphones into my smartphone or directly into my PC allowed much louder volumes, so I suspected there was a PC software issue at the heart of this problem.

I switched several times between the BMR ear speakers and my headphones with the BMR’s working well enough in rhythm music games like Beat Saber, although the bass still lacked weight and the music needed to be much louder. The headphones got hot in Beat Saber adding to overall heat stress when playing Expert+ levels.

As the Index controllers have the higher quality HD LRA haptic motors, some louder audio and bass were much needed to match the controllers’ haptics and provide the all-important “sensory consistency” for VR immersion. 

For quieter, non-gaming applications, a great example being Wevr’s “The Blu”, I found the background noise a real problem with the BMR’s as it dramatically reduced the quality of my experience.

The otherwise amazing “Reef Experience” at 144hz and 2.0 supersampling on the Index was overpowered by the noise of my PC, the base stations and road traffic vehicle noise in local streets. It was much better when used with headphones to block the background noise and since its not an active experience, there was no heat issue.

On a number of early mornings I moved my PC into the corridor outside the VR room, road traffic noise was minimal although the base stations still made their whining presence known when using the BMRs.

Wide face cushion arrives

Thankfully after weeks of discomfort using the standard (narrow) face gasket, I tracked down a file by Anonymous Hermit for 3D printing a modified “wide” face gasket plastic base.

As was explained in my first article, I had found the Index’s standard face gasket to be too narrow for my average width face which had caused facial discomfort, optical misalignment and a need for constant adjustment

The 3D printed version soon arrived from Ninja Prototype in China, I faced it with industrial-strength Velcro to mount aftermarket Vive face cushions which worked well, but fitting the wide gasket had the unfortunate effect of further reducing clearance for a headphone cable if wanting to use separate audio headphones.

Initially, I failed to find anything that would fit, all headphone leads or their strain relief sleeves fouled the wider plastic base of the face gasket, causing it to lift off the magnets used to secure the face gasket’s plastic base into the headset faceplate.

(left) Standard face gasket just fits the headphone cable. (right) Wide face gasket being pushed off headset

After hacking a short Logitech headphone splitter cable (for microphone and headset setups) by cutting off one lead and shaving down the molded strain-relief sleeve on the remaining 3.5mm jack plug, it was just thin enough to sit behind the face gasket.

When fitted to the Index with some velcro wrap securing the lead to the head strap it provides a short extension lead to bypass the face gasket with a 3.5mm audio output socket at the end (just like the original HTC Vive) for plugging any headphones into.

Index audio lead
Index audio lead allowing use of headphones with wide face gasket
Equalizer APO vs. Nvidia GPU driver

Despite my mods, I still couldn’t get enough audio power to my headset, a problem I’d also had with my previous headset, a Lenovo Explorer WMR, which had been used on the same PC earlier in the year with separate audio headphones.

Thankfully, the VR community came to the rescue with talk of using Equaliser APO to solve this “low volume” problem by adjusting pre-amplification. I’ve never heard of it so I looked it up on-line and found out this:

Equalizer APO is a parametric / graphic equalizer for Windows. It is implemented as an Audio Processing Object (APO) for the system effect infrastructure.

It’s a free download made by Jonas Thedering, and crucially importantly for the Index ear speakers, it can access audio pre-amplification where an adjustment needs to be made.

From reading through the research, I found out the Nvidia graphics card driver was applying a -6 negative setting in the pre-amplification stage of the graphics card’s audio system. Plugging my headphones straight into my PC bypassed this problem, as the motherboard audio sockets run off the motherboard’s onboard audio with its own drivers and not through the Nvidia graphics card.

This was causing significantly less power to be available for audio on any VR headset which was connected to a Display port or HDMI port on my Nvidia RTX2080Ti graphics card. I downloaded Equalizer APO and installed it on my PC, a bit confusing at first but after slowly going through the various settings I found the pre-amplification control panel.

Equalizer APO valve index
Equalizer APO screenshot

After running the “Configuration Editor”, I added my Index HMD and restarted Windows.  After the restart, I opened the configuration editor and could now see my Index as the primary audio, so I adjusted the pre-amplification gain first to +8, and then later to +10.

The difference was immediate with a big increase in volume level, the audio performance of the BMR ear speakers dramatically changing as they “came to life” with a much fuller sound with punchier bass, finally!

I found this gave me the ability to go plenty loud and easily block out background noise in many applications whilst still only using ¾ of the volume slider in SteamVR. 

Warning: It’s easily possible to set the gain value too high and potentially damage your hearing, the ear speakers or both.  Be careful with the volume settings! 

It’s very easy to adjust Equalizer APO from inside VR by displaying the configuration editor on your desktop so you can view it inside SteamVR and make any adjustments you need. As well as pre-amplification, it is a full-functional equalizer, so have fun playing with your sound. It might well help with some applications that have poorly mixed audio or require bass adjustment.  

Asymmetrical ears

With the volume levels now more than sufficient, I quickly noticed a new challenge, my left ear was feeling more sound pressure (i.e. too loud) whilst my right ear felt comfortable, there seemed to be a difference maybe a left/right volume balance issue?

Everything was as normal so I tried reducing the left side volume, but this started allowing background noise to bleed into the left side with unwanted results and reduced the “soundscape” with a bias to the right (where the higher volume was playing).

Next, I decided to perform a simple physical check: how much gap was there between each ear speaker and each of my ears? It is hard to look at yourself whilst you are wearing a headset and there was no one around to take a photograph. Sliding a finger up, I found a generous gap on the right, but much less gap on the left, it was much closer to my ear.

valve index speakers asymmetry
View of the fit of the left and right speakers to the ears. The difference is noticeable and meant my left ear was getting too much sound pressure

Taking some photographs later on showed what was now obvious: human asymmetry at work! Human beings are surprisingly asymmetric with subtle variations shown across our heads, hands and bodies.

As immersive computing technology develops and we reach towards retina display, these subtle variations of human asymmetry will need accommodation, something I’d already experienced with the higher resolution Index which benefitted from making ergonomic adjustment to suit my face and hands – these ear speakers are no different in that a “good fit is a good fit”.

After looking again at the ear speakers, I still saw no depth adjustment to cater for this common occurrence of slightly different shape/size ears. Over-ear headphones or on-ear headphones cater for such asymmetry without many issues by using a sprung, adjustable headband design.   This tends to work well unless the individual is an outlier, but with such a huge range of different headphones on the market something can often be found by doing some research.

Firmly holding the right BMR ear speaker and headband, I tried manipulating the mounting to pull the speaker further away from my head but there was no meaningful adjustment, just a slight movement but no permanent gain and any increase in force just threatened to snap something internally.

Trying to change the depth of the speakers of the Index, with no success, just concern about snapping something plastic

I reached out to Valve, not expecting to hear back, but to my surprise, I had a reply by email from one of Valve’s hardware engineers:

RC: “Due to my natural asymmetry I find the left speaker very close to my ear, whilst the right speaker has a noticeable gap to my right ear. I’ve been looking at this again, obviously the speakers do not have a depth adjustment to accommodate this asymmetry. One idea is a spacer with matching contact pins to move the left ear speaker outwards so the spacing gap becomes equidistant. I call this a  “Pogo Biscuit” and am building the spacer to test the concept”.

Valve: “There is actually a little bit of horizontal flex in the speaker arms. If you press lightly and hold them in towards your ears, you might find it does result in a small noticeable difference in volume. If this is enough to compensate for your particular case, then a possible solution might be as simple as putting a wedge between the speaker arm spring and the head strap to hold it closer permanently on the side it’s not loud enough. In the long term, we are actually looking at better accommodating horizontal positioning of the speakers for future revisions of this hardware. It’s great for us to get this feedback, so thanks again for the email”.

The idea for a “Pogo Biscuit” came about when thinking about a simple way of adjusting the speaker depth: rather than trying to redesign the mechanism, simply move the mounting point for the left ear speaker 10mm further off the headband to create a larger ear gap.

Pogo biscuit

During the wait for my ear speaker RMA, I spent some time working on my “Pogo Biscuit” idea. I wasn’t quite sure how to manufacture it or even build a prototype as the spacer would need to be very small whilst containing 2 electrical-pin pass through and providing the “key” shape to mate with the Index’s head strap and the ear speaker itself. I was aiming to replicate what was already there, but with a 10mm extension.

Pogo biscuit research
Work in progress with experiments on the Pogo Biscuit

Providence smiled as the next day there was a post on the Valve Index subreddit from the Anonymous Hermit, asking Index owners for accessory ideas so the Hermit could do some more CAD modeling and 3D printing. I reached out to Anonymous Hermit and sent them my idea for the “Pogo Biscuit” which the Hermit liked and got to work on.

The following day, an email appeared with a link to their design of “Valve Index Speaker Spacer” on Thingiverse with 3 different depth biscuits at 10mm, 5mm and 2mm to allow fine tuning if required.

Pogo Biscuits on Thingiverse
Pogo Biscuits on Thingiverse and my 3D printed samples

After finding a 3D printing company in London with low minimum orders I asked them to print all 3 depths of spacers so I could experiment and have some spares.  £40 and a week later I had a bag full of printed spacers and set to work making a working prototype using one of the 10mm spacers to test out the theory which seemed sound enough.

Figuring out the contact pins was tricky, as the ear speakers use “pogo pins” which are spring loaded to take up any variance when fitted, the spring loaded pins pushing tight against contact pads to maintain good electrical contact. There was no simple way to build such small, spring loaded pins, so I went shopping for headphones but I could not find any using pogo pins that could be cannibalised for my Pogo Biscuit prototype.  

I took careful measurements and I realized that if I built accurately the connection, it would work without pogo pins as long there was good metal to metal contact without excess pressure on the contact pads.

Looking at the wheel of my bicycle gave me a lightbulb idea: I could use bicycle spokes which are threaded at one end for the fitting to the spoke nipple. I found some steel spokes and screwed them through the hole already moulded into the spacer, which let me fine tune the contact depth so that the pogo pins on the ear speaker would compress to make electrical contact but without being crushed.

“Pogo Biscuit” being built, checking depth of spokes before cutting male side

I then cut down the spokes on the other side and slowly reduced the length using a Dremel tool by cutting and re-checking against the headset mount.

Grinding spokes to build the Pogo Biscuit prototype

I built two prototypes (one a bit scuffed from catching the Dremel), fitting the best looking prototype to my Index headset which showed the idea worked really well and took care of my asymmetry problem.

valve index how to solve asymmetry
Pogo Biscuit solving the asymmetry problem

Producing these “pogo biscuits” at scale was going to be expensive as it would need pogo pins and tooling for injection molding of the spacer as there was concern about the fragility and long term durability of these small parts when 3D printed.

5.4 degree ear speaker spacer

Soon enough, Anonymous Hermit was back in touch, with a simpler but smarter take on the ear speaker asymmetry problem. Instead of building the Pogo Biscuit with its difficult to construct pogo pins, they presented a much simpler design for a “5.4 degree ear speaker spacer”.

They had worked out with some maths the correct angle for a subtle wedge which would place the speaker pod further off my head whilst maintaining the correct angle to face the ear. 

5.4 degree spacer on Thingiverse
5.4 degree spacer on Thingiverse

The design was hosted on Thingiverse but Hermit kindly sent some spacers free of charge so I owe them a beer if our paths ever cross in person. About a week later, a small envelope arrived with a USA postal stamp, containing a selection of 5.4 ear speaker spacers printed in an orange-red colour.

Spacers arrived directly from the US thanks to Anonymous Hermit

Fitting these to the left ear speaker was easy although fiddly, reusing the existing T6 fitting. I found it useful to “load” the spacer onto the speaker before gently lifting it up to the headset so the spacer does not shift. As I wanted to increase the distance between left ear and left ear speaker, I orientated the spacer with its wider section at the bottom, causing the ear speaker to move further outwards.

spacer for speaker of valve index
Ear speaker with the 5.4 spacer designed by Anonymous Hermit

Depending on the orientation of the spacer, it’s possible to move each speaker further in or out from the fixed position giving an extra depth adjustment for those with asymmetrical ears and heads.

This smart idea is simple to print and adds a vital ergonomic adjustment to the toolbox of the Valve Index owner. Fantastic work by the Anonymous Hermit in providing a very neat, precise solution to the ear speaker asymmetry issue. 

valve index asymmetry adjusted
The asymmetry has finally been adjusted and both ears are being equally blasted with sound

As I often mention in my articles, an extension of this ear speaker spacer idea would be using 3D head mapping to determine optimum depths on a per ear basis.

Many Valve Index speakers on my desk…thanks to Steam Support…for the support!
BMR ear speakers or separate audio headphones?

With the ear asymmetry taken care of using Anonymous Hermit’s “5.4 degree ear speaker spacer” and the low volume problem banished using Equalizer APO, I felt it was a good time to rethink the choice of using Index with the BMR ear speakers or with separate audio headphones.

One question, is it better using BMR ear speakers or separate audio headphones?

  1. Depends on your environmental situation (background noise)
  2. Depends on the application (music rhythm game or quiet ecological experience).

With my asymmetry addressed and volume raised I came to very much prefer the BMR ear speakers with their excellent sound quality and reduced onboarding “friction” over my separate audio headphones.

The BMR speakers sounded very good whilst the off-ear design kept ears cool and untouched by headphone cushions, a great quality of life upgrade for VR headsets.

The feeling of having nothing on my ears was really appreciated when playing fast games of Beat Saber and Pistol Whip; the reduction in heat compared to wearing over-ear or even on-ear headphones was substantial.

If you’ve ever gone jogging in headphones you’ll understand why earbuds are better for active movement. The BMR ear speakers provide the same lower temperature benefit but with far superior sound quality to any earbud and many headphones.

In terms of pure sound quality (compared to studio-quality audio headphones) I felt they still slightly lacked bass, which is something I read that the manufacturer Tectonic had worked on during the development of these custom BMR drivers with Valve. But with higher volume levels in applications with well mixed audio they had a good bass weight which was satisfying in Beat Saber or shooting games.

Even more impressive, though, was the openness, depth and size of the VR soundscape the BMR ear speakers created by interacting with my ears and head’s physical anatomy to provide the best audio I’ve ever heard in a Virtual Reality headset.

Something to note though is that they will quickly expose any applications with poorly mixed audio, and there are many out there, especially older titles. In contrast, the recently released Pistol Whip really shows off the BMR ear speakers at their best with an incredible audio experience where the BMR ear speakers really shine.

Pistol Whip Valve Index
Playing Pistol Whip with the Valve Index

For people with constantly noisy backgrounds, the BMR ear speakers may not be ideal, you would have to increase volume to dangerous levels to block out background noise, and during quieter “experience” type applications, even a high volume level would not block out background noise.

Potentially for LBE (location-based entertainment) and Arcade operators using Index, the preferred choice could be gaming headphones for sound isolation where numerous users are in neighbouring booths, although this would need to be balanced against the increased friction of using separate headphones.

For the Index’s intended market who will set up dedicated VR spaces (it’s only sold B2C at the moment to early adopters and enthusiasts) the use of headphones is a genuine solution for more noisy environments, or if the user wants a heavier bass for their rhythm title.  This has to be weighed against the increase in body heat, ear discomfort and onboarding friction from using separate audio headphones.

The Takeaway

Summarizing, the main points about the Valve Index speakers are:

  • High-quality drivers with great clarity and separation
  • Big open soundscape that feels more “real” in VR
  • Bass is less weighty than studio quality headphones but still sufficient at volume
  • Lack of contact with ears lowers overall body heat stress
  • Lack of contact with ears means no pressure from ear cushions = less stress
  • Reduction in onboarding friction improves “quality of life” for regular use
  • No “depth” adjustment to move speakers closer to or further out from ears
  • Speaker depth can be adjusted with 5.4 degree ear speaker spacers
  • Lack of power was due to Nvidia GPU driver setting -6 in pre amplification
  • Nvidia GPU driver issue can be resolved with Equalizer APO
  • Noisy environments may require headphones i.e. gaming arcades, festivals
  • Quieter applications may require headphones if background noise is present
  • Not all headphone leads may fit due to limited clearance behind face gasket
  • Wide face gasket users will need slim extension lead as clearance is very tight

And this closes this series of posts by Rob Cole, that I want to hugely thank for these high-quality detailed articles on the ergonomics of the Valve Index. Many people asked me questions on these posts, and I will be very happy to put you in touch with Rob for whatever question or collaboration proposal: you just have to shoot me an e-mail!

But before, make Rob feel your love about these posts with some nice comments!

Thanks for reading! Rob Cole, immersivecomputing.org

Categories
ergonomics

Valve Index : controller ergonomics

Originally published by Skarredghost in November 2019. Edited to correct my original spelling mistakes and some images updated. All images copyright of immersivecomputing.org unless otherwise indicated.


Introduction by Tony @ SkarredGhost:

“Today I publish the second part of the interesting deep dive on the Valve Index comfort by Rob Cole. If you lost the first part, you can read it here.

Who is Rob Cole? Rob first tried VR in 1991, and has become an enthusiast of the tech ever since. Because of his background in industrial design, he has always had a strong interest in the design and the ergonomics of the VR headsets. At Immersive Computing (see his Instagram account) he carries on this interest, exploring the technology always starting from the human perspective, putting the human at the centre of his experiments and analysis. This post is the result of such kind of experimentations on the Valve Index headset. I hope you will enjoy it!”


For this second article, we will concentrate on the Index Controllers; the first article has already covered my experiments with the Index Facial Interface, whilst a forthcoming third article will cover the Index Ear Speakers.

index controllers how to improve comfort
A bunch of Valve Index Controllers fitted with 3D printed “Palm Boosters”

So how are the Index Controllers according to Valve?

Designed from the ground up to enable natural interactions, high-fidelity hand presence, and long-term comfort.

The Index Controllers

When my Valve Index arrived on launch day (28th June), the first item I removed was the right Index Controller, the headset didn’t even get a look in. 

“Knuckles” had arrived and were now in my hands…

Right Index “Knuckle” controller, freshly removed from the box

It felt reassuringly heavy (196 grams) and looked well built with a premium look, although both A/B buttons and the trigger felt a little wobbly, and perhaps a little out of place here. 

Talking of quality, despite the joysticks being a big improvement on the Vive Wand trackpad, the Index joysticks did not have the tight, precision feel of the sticks on the official gamepads for Xbox and PS4; for the high price of the Index controllers I expected better quality joysticks – something that would come back to haunt Valve?  

For weight comparison, my Oculus CV1 Touch controller weighed in a little lighter at 160 grams including 1 rechargeable battery.

The Index controllers were smaller than they had seemed in photographs but felt denser than their measured weight, indicating that there was much going on inside.

I had read it was packed full of many different sensors; looking closely I could see optical windows across the plastic shell for the Triad Semiconductor TS4112 Photodiodes that are used for the SteamVR 2.0 tracking system. According to Valve:

Each controller uses 87 sensors to track hand position, finger position, motion, and pressure to determine user intent. All of these signals, combined with fine-tuned software and algorithms, give us a better understanding of how a player is holding and using the controllers.

Joysticks and pill-shaped touchpads were around this time, finally, a much-needed step forward after the touchpad of the Vive wand became very stale following the release of Oculus’s mighty Rift CV1 Touch controller designed by Carbon.

I’m feeling prominent A and B buttons (as mentioned both a little wobbly), a guarded system button, wide trigger with a click at the end of its travel, capacitive sensors for finger tracking and force sensor for grip, the image from Valve shows the controls highlighted in yellow.

Valve index controller
Image of the Valve Index Controller with interactive areas highlighted in yellow (Image by Valve)

I quickly removed the second controller from the box and shoved both my hands into the controllers, tightened the straps with some fumbling and then violently shook my hands with my fingers open, the controllers stayed strapped in place, very cool!

Index controllers staying firmly attached to the hand

Known as “Knuckles” during their long development, these have been highly anticipated by the SteamVR community as an alternative to the HTC Vive “Wand” controllers with their simple ‘hand tool’ design and crude yet unreliable trackpads.

So what is going on here?

Some very different thinking from Valve here, to design a VR controller which does not need to be constantly held.

Each controller has a soft hand strap wrapped with a similar antimicrobial tech material as the facial interface; the controller is held by the strap (dorsal side of hand) pulling the palm (palmer side of hand) against the controller body, with the strap / controller body sandwiching the hand in place so you don’t need to constantly hold the controllers, you can rest your hands.

To help you understand, below is an image showing the four faces of the hand, “Palmer” side is your palm side and “Dorsal” back side of your hand whilst the Lateral and Medial borders are the “edges” of the hand; the Medial border would be your “karate chop” edge.  

Physical Reference system of the hand

The strap has an elasticated cord at its base mounted off a plastic turret which passes through a slot at the base of the controller, with a spring loaded button operating a clamp that locks the cord in place.

With practice, it’s easy to tighten the cord using a single finger, and release the cord with a pinch action whilst wearing the controllers.

The strap itself is also slightly elasticated, with the top terminating in a pivoting toggle which is fitted to a spring-loaded plate allowing 4 different positions relative to the controller body.  A carefully shaped piece of steel plate forms the backplate of the control face before extending out to support the tracking ring. 

The various part that compose the fitting system of the Valve Index Controllers

With the strap at resting tension I took quick measurements between the middle of the strap to the inside edge of the controller grip body and got 50mm – 45mm – 40mm – 35mm distance as I tried the 4 different settings. 

Additionally, I can see that the available volume between the strap and controller body is changing (this is not so easy to measure), with the pivot at the top allowing the angle of the strap to be altered as the strap position and tension is adjusted.

Overall, the range of adjustment is impressive and since designing and manufacturing hand controllers to suit many different hands is very difficult to implement, Valve must be congratulated for this feat.

One thing to check with your setup – due to human being’s inherent asymmetry its very common for people to have different volume sized hands (as left / right feet can be ½ size different). You may find you need your left and right strap notch positions set differently to work best – see what works best for your hands.

The long hot summer of RMAs – part 2

It’s no secret that there were some issues with the Index controllers following launch on June 28thspecifically with joysticks not always clicking or actuating in all directions.  There was perhaps some miscommunication about the reasons why, which the gaming community pointed out was ahem…wrong…holding their Rift, PS4 and Xbox controllers as evidence.

valve index controllers rma
Returning controllers…thanks to Valve for free return shipping

Both my launch pair and my replacement pair had no click nor actuation when pushed forwards and backwards with the left controller joystick, or left and right with the right controller joystick. The RMA process was relatively painless though it took 2 weeks each time from sending them back to receiving a new pair.

So I bought an Xbox One controller and thoroughly enjoyed spending some time doing seated VR with games like Assetto Corsa, House of the Dying Sun, Hellblade: Senua’s Sacrifice and Aircar which had just been released as an updated version free on Steam (previously this was used through Revive and my Oculus library).

xbox controller vr
We always think about VR controllers, but sometimes also a gamepad can offer some enjoyable virtual experiences

Thankfully the replacement pair (pair #3) did not have the joystick problem and a number of Index owners on the subreddit started reporting that later production date controllers have been shipping without the misfunctioning joysticks.

Some people buying full kits reported that they found their controllers were from earlier manufacturing dates and required an RMA to replace with more recently manufactured controller stock. There is even a spreadsheet on Reddit where people receiving replacements are invited to log the date of manufacturing and report any issues.

However there are other issues now being reported with the more recent controllers of joysticks developing “drift” and loud squeaking triggers.  I felt lucky, for a while…

but after a month of light use (6-8 hours a week) pair #3 developed a loud squeaking in the right trigger, loud enough to be heard in VR, and a wobbling left joystick that is laggy when using free locomotion in VR or even just trying to teleport around Steam VR home environments.

Checking if new Index controller joysticks click or not?

Valve has supported my latest RMA request with an “advanced replacement” pair on Index controllers, so I didn’t have the usual 2 week turn around. These come from a warehouse in the Netherlands, which is where Indices for European customers are stored.

4th time lucky perhaps? Time will tell, back to the findings…

SOMETHING FEELS ODD THOUGH…

Index Controllers are strapped to hands rather than held as normal, this in itself immediately presented two “challenges” for my hands.

First, the dorsal side of the hand is unused to pressure as its pretty much unused in everyday life, unlike the palmer side which is familiar with contact as we hold objects by using fingers to pull objects against our palms (try picking up your smartphone).

The skin of the palmer side including the fingers is tough, thick and hairless with your fingerprints (double rows of papillae) help you grip objects as well as protect the skin from ripping.

If I wear a pair of gloves, these provide a cushion between my palm and whatever it is I am holding, gripping or pushing against – gloves also make light contact with the dorsal side, lateral and medial borders (sides of hand) as well as the palmar side – “wrapping” the hand in an envelope of fabric, that with a well-fitted glove can become almost “transparent” in use. 

Straight away with the Index controller I have the odd sensation of having something clamped across the back of my hand, it’s unusual as it goes against a lifetime of not having anything clamped across the back of my hand! 

These sensations do tend to fade over time as the body becomes accustomed to new sensations but it’s certainly an odd sensation and initially feels more intrusive than holding a HTC Vive Wand or the Oculus CV1 Touch controller (often held as the “Gold standard” for VR controller design).

vive wand vs oculus touch
Vive Wand compared with the Rift CV1 Touch controller

The second challenge was caused by a material mismatch – the soft fabric strap against the dorsal side which felt weird (from contact) but not uncomfortable unless overtightened; and the hard plastic body of the controller against the palmer side which felt normal (used to contact) but a bit uncomfortable.

The tighter the strap was pulled (increasing tension) the more the mismatch was felt, like a hard plastic bar being pulled against my palm rather than a comfortable controller. The controller body felt a little too narrow with not enough width at the top where the index finger and middle finger sit.

The hard plastic also proved slippery when getting hot and sweaty playing fast paced games,  allowing the hand to move around despite being strapped tightly in place – some texture to the plastic or an alternative rubber-like material choice could have helped.  

The strange sensations of the Index controllers almost felt like Sensory Processing Disorder, my hands didn’t feel like my hands in VR or that my hands were holding VR controllers, generally a bit odd perhaps causing a proprioception issue.

Proprioception, or kinesthesia, is the sense that lets us perceive the location, movement, and action of parts of the body. It encompasses a complex of sensations, including perception of joint position and movement, muscle force, and effort. These sensations arise from signals sensor receptors in the muscle, skin, and joints, and from central signals related to motor output. Proprioception enables us to judge limb movements and positions, force, heaviness, stiffness, and viscosity. It combines with other senses to locate external objects relative to the body and contributes to body image. Proprioception is closely tied to the control of movement.

Definition of proprioception, Encyclopedia of Neuroscience

Proprioception relating to body image is very interesting, here is a simple experiment:

Try closing your eyes, move your arms above your head; now try touching the end of your nose with your right index finger – I’d be very surprised if you miss?

Another test, place a piece of paper on a table in front of you, sit and then draw an “X” in the middle of the paper.

Take a look at the X, close your eyes, raise your pen arm up and then bring it back down to where you think the X will be, make a mark, open your eyes, try again several times and see how your accuracy improves, this is proprioception recalibration on the fly!

We maintain a surprisingly accurate body image based on the rich wealth of proprioception generated as we inhabit our bodies, which can be leveraged with interesting results when using immersive computing platforms like Virtual Reality. 

However, if things feel “off” then it’s immersion-breaking because it causes an irritation that is eventually impossible to ignore, like a stone in your shoe that needs to be removed because it’s distracting your running. Something weird was going on with the “Knuckles”.

Is the controller body a little small?

Strapping my hands back into the Index controllers, I spent a considerable amount of time trying the 4 different positions and varying the strap tension in each position. With fine-tuning, it was possible to get an effective working position where the controller stayed in place without the back of my hand facing uncomfortable pressure.

This then led to a strange situation where I was having problems reaching the controls with my hands strapped correctly in place – my thumb was too far forward relative to the joystick, to get my thumb located correctly I had to pull it back at an uncomfortable angle, or loosen the strap and slide my hand back slightly, which then meant the controllers weren’t strapped securely to my hand!

valve index controllers comfort
Users must decide between comfort of the hand and correct thumb position…

Despite the less than ideal fit, I carried on using them and managed to get the finger tracking to work effectively but I found the “reach” for the joystick, trackpad, and buttons continued to be uncomfortable.

The Trackpad

The trackpad has changed, it used to be a large circle on the Vive wand, but has been reduced to much smaller, pill-shaped design on the Index.

A look back at the 3+ year development of the Knuckle controllers show the joystick was a relatively recent addition with the earlier development units having a large trackpad like that on the Vive wand.

It’s been reported that Valve did not have a liking for free locomotion in VR, preferring teleport, but have since come around to the free locomotion used in many popular games, hence the inclusion of a joystick whilst keeping a trackpad.

The inclusion of both control systems (pad and joystick) is noticeable because the axis of my thumb does not seem to fall naturally on one or the other. With the right controller, I need to deflect my thumb slightly to the left to use the touchpad and deflect my thumb considerably more to the right to use the joystick.

It felt like both were “off-axis” and it was a little uncomfortable. As I finding the controller a little small and my thumb too far forward, this deflection was probably more extreme than with a correctly fitting (larger?) controller body. 

Deflection of thumb from its natural axis

The trackpad itself is no technical slouch, but due to its limited size and “pill” shape it can be awkward to use with any accuracy especially for people with larger hands and bigger fingers.  

I would prefer an Index controller with no trackpad and just a high quality joystick on the correct axis to naturally fall in-line with my thumb, perhaps a revision for the next generation of controllers? (thanks Valve!)

Can the fit be adjusted?

As a “sample size” person (medium everything, including medium-size gloves) I’m certainly not an outlier in terms of size; this left me wondering if the Index controllers did not fit my somewhat average-sized hands, what about everyone else? 

After looking at the controllers for far too long one evening trying to figure it out, it dawned on me that increasing grip volume on the palmer side (hard plastic body of the controller) could improve the fit of my Index controllers.

Using the same principle of offering fitting choice, for example “narrow” and “wide” facial interfaces for the original HTC Vive, perhaps there was a way to adjust the volume of the controller body to suit different sized hands?

I tried wrapping the body of the controller with masking tape and then strips of card which increased the grip volume, and also increased the reach to the controls giving a more natural thumb position with less deflection to reach the joystick. 

Despite the loss of finger tracking during my crude hack, it showed a volume adjustment “skin” or clip-on spacer could work.

A crude experiment to improve the comfort of Valve Index controllers
The “Boosters” arrive

Soon there is encouraging news that Valve are releasing a set of CAD files for the Index under the Creative Commons License, and these include “Palm Boosters” as well as the “Frunk” dimensions and sensor exclusion zone maps.

This forward thinking by Valve gave a gift to the modding community with an invitation for people to hack the technology for their own purposes. Their previous collabaration with HTC, the Vive, was openly designed to be hacked and received many “frankenmods” as well as official upgrades like the Vive DAS. 

I quickly download all the Index files and use my .stl viewer to closely inspect the Palm Boosters, a very simple but effective design with intricate support and weight reduction latticework on the inside.  

valve index controllers booster
CAD Image of the booster

The 3D printing shops were soon busy printing Palm Boosters, I used Printlix in Romania through Etsy.com, and chose Boosters in a very bright yellow color so I wouldn’t lose them in my VR room. Surprisingly they only cost £22.38 in PLA (polylactic acid) including shipping with a estimated 3-5 business days before arrival.

The boosters soon arrived. Examining them closely, I could see they were well printed and had a snug fit when clipped into the controller body. They were a little crudely finished around the cut-out for the lanyard release button, which could be easily finished with some wet and dry grit paper so I left that for later (maybe one day…)

Valve Index Controllers and yellow boosters

The “boosted” surface facing the palm of the hand has a slightly rough texture from the additive printing process, which is very useful as it provides a slightly warmer feeling and more tactile surface increasing my hand feel and hand control; truly a good thing for active gaming where the slippery body of the controller was not ideal.

The difference in fit was immediate, I took some measurements across the middle of the controller body and got 36mm wide / 35mm deep for the ‘naked’ controllers and 40mm wide / 40mm deep with the Palm boosters fitted.

Valve Index controllers with boosters
Valve Index controllers with boosters installed

Pushing my hands into the controllers, I start setting them up again and I noticed less strap tension was required, and my thumb was now falling into a more natural position for the joystick, trackpad and A/B buttons.  The amount of deflection to reach the touchpad  and joystick is lessened as my thumb is now further away.

The thumb felt much more comfortable with the boosters

The reduction in strap pressure and warmer feeling material have changed the feeling of being tightly strapped to something narrow, hard and obviously plastic, to a more warm sensation of a comfortable contact without edge pressure.

The big improvement of fitting and more comfortable contact, along with time spent using the controllers has reduced my “proprioception challenge” to a level where the Index controllers are feeling good in my hands.

Without any doubt, the Boosters have transformed the fit of my Index controllers, and Valve should be congratulated for releasing the CAD file to enable this important final fitting piece of the controller puzzle to be completed.

I liked my boosters so much, I got a spare pair from Etsy.com and Printlix a few weeks later, this time in “mystic green”…

Classier mystic green boosters

One consideration, and not one I needed to test myself as the Valve Palm Boosters worked great for my medium-sized hands, is whether someone with larger hands would benefit from a “larger volume” Palm Booster design?

It should be relatively easy to manipulate the CAD file and increase the volume on the Palmer side to suit larger hands, and this is something I would encourage any large-handed people to try out as a solution for Index controller fitting issues.  

Ultimately a method of 3D scanning the hand and creating a custom Booster, per hand to accommodate our inherent asymmetry, would be the ultimate ergonomic modification for these interesting hand controllers.

It is arguable that they are so important for fitting medium-sized hands, and as some on the /r/valveindex subreddit have reported, even for fitting smaller hands –  a question then for Valve is whether the Palm Boosters should come standard in the box with the Index controllers

What about the games then?

Whilst I’m not here to list which game worked or didn’t work with the Index controllers, I did find some games simply refused to load or work with my Index, whilst some only worked after messing about with controller bindings.

It seems that all the VR applications on Steam are listed as being compatible with “Index” whilst this is blatantly not the case, it’s down to developers to update their applications. 

At times Steam refused to save my bindings, but the binding system seems to be working much better now, and there are lots of community bindings often better than those from official developers. 

I did find the finger tracking to be little more than a visual gimmick in some titles, whilst a few really took the concept and ran it with. At times the Index controllers behaved and felt just like using a Rift CV1 Touch controller, which is no bad thing!

“Aperture Hand Labs” and “Moondust” were already installed on my PC, and perfect examples to showcase the Index Controllers finger tracking and force grip sensors.

Aperture Hands Lab demo by Cloudhead Games and Valve

Playing rock, paper, scissors with a maniacal robot was great fun, with an awesome Aperture vibe of the Portal variety, a great experience for Valve, Portal and Half Life fans no doubt!

Moondust had some very cool gravity manipulation and hand grenades, rocks to crush and radio control moon buggies to drive about on the lunar surface; whilst I didn’t really get anything from the rocket kit assembly experience.

Technical demo Moondust

More importantly, Valve updated THE LAB with its “Hands-On” update!

The Index update brought finger tracking, enhanced audio and physics to The Lab, easily my favorite VR application to date and one that at 144hz and 250% supersampling using my RTX2080Ti has an unreal, “skin tingling” feeling of presence.

More easter eggs abound with a Knuckles development kit box waiting to be knocked off an overhead rafter with your bow and arrow. This update to The Lab’s physics is brilliantly demonstrated by your hand controllers haptic interactions with your canine robot companion, producing a metallic bumping feeling as you run your hand across his body.

The update to The Lab is very timely because it shows where Valve’s technology is moving and it runs beautifully at 144hz; I look forward to many more hours playing the mini-games or just hanging out drawing bad pictures on the whiteboard and shooting the warehouse workers, or adjusting my playspace to find hidden spaces 😉

A Valve Index controllers’ box inside The Lab

These applications showed the real potential of the Index controllers, it’s now down to developers to implement proper Index support in their existing applications and for any new applications coming to Steam. 

Oculus games using Revive on Index ran very well, seeming to treat the Index controllers just like Touch controllers, with Robo Recall being a standout with the grip feature on Index letting me equip my side holstered guns with better accuracy than on Touch.

Some games surprised me in that the Index controllers didn’t feel as good in the hands as other controllers due to the style of gameplay, the first being Beat Saber.

Beat Saber grip?

I found with Beat Saber that the hand straps massively hindered my slashing actions by strapping my hands to the swords instead of allowing me to flick my wrists like with Wands and Touch. 

I slipped my hands out of the straps by backing them completely off with the strap on setting #4 to give maximum space which felt better.

I then found the boosters didn’t play nicely with unstrapped hands as they moved slightly sometimes creaking so I removed them – Beat Saber has ridiculously fast controller movements so it’s not surprising a “clipped on” piece could feel loose during frantic gameplay. 

Then I tried moving my hands further down the controller body until I found a very natural perch around the intersection with the tracking ring which felt like the Pommel (base) of a sword – perfect for Beat Saber.

how to valve index controllers beat saber
How the Index Controllers felt the best when playing Beat Saber

It was much more comfortable, allowed super-quick wrist flicking and never felt like I would lose a controller despite my “energetic” attempts at what could be called dancing in Elixia by Mord Fustang. It’s probably a good thing that VR generally takes place alone in dark rooms…

This change of hand position on the Index controller gave a feeling more like the classic Vive Wand, which is arguably still a great “tool” for Beat Saber with a physical shape that feels like holding a sword or saber.

The other genre of game I found didn’t work so well strapped into the Index controllers was my favorite “In Death” the brutal Rogue-like first-person bow shooter. I also tried other shooting games which required fast trigger work such as classic “Space Pirate Trainer” and found a similar issue.

Bow Grip?

Strapped in, my left hand (bow hand) felt less precise when aiming at distance or headshots, and my right hand (arrow notching and teleport arrow) felt slightly restricted by the strap on the right controller.

The strap runs across the knuckle and tendon for my trigger finger, causing a slight feeling of drag.

If you work your trigger finger and watch the backside of your hand, notice all the movement going on under the skin up the index finger, across the index knuckle and across the hand into the wrist as the tendons move under the skin.

I like to play In Death with a fast, aggressive playstyle and actually found the Index controllers a step back after some blistering runs using the Touch controllers on the Rift CV1.

So I slipped the straps and found a great “loose” setup with a Bow hand pose stabilizing the aim, and my trigger hand unimpeded by strap pressure. Using the loose controllers also helped with faster reactions when getting jumped or mass spawnings of bad guys when teleporting into a location.

Best bow grip I found for “In Death”

Space Pirate Trainer also felt much better unstrapped, with a faster trigger finger action and easier over-the-shoulder grab for the shield.

The great thing to realize is you don’t always have to be strapped in, and you may find better hand positions for different games or experiences. You should have received lanyards with your controllers, and I’d advise using them if playing unstrapped as there is potential for a controller to part company with your hand when unstrapped with expensive or painful consequences!

Xbox One Controller

Some VR games require a gamepad controller, whilst others might just play better with one – a great example was “Aircar” where you fly around a city in a BladeRunner-esque flying vehicle. It was a favourite on Oculus, and has recently been updated for Index and added to the Steam store still as a free download.

aircar valve index
The amazing Aircar experience…free on SteamVR. I’d happily pay good money for this!

Whilst Aircar was perfectly playable with the Index controllers, apart from some issues with the “Turbo” button and being able to access in game settings, it felt considerably more natural using the Xbox controller which gave the physical feel of a flight “yoke” as you’d use in a light aircraft.

Trying to hold the Index controllers next to each to simulate the yoke felt like an effort, whilst the Xbox controller just melted into my hands. This is similar to trying to play shooters like Onward and Pavlov using motion controllers without a gun stock, i’ts not great!

Aircar is a super chilled experience, so anything that can increase immersion is a great thing and this instance the Index controllers felt redundant with the Xbox controller proving a much better hand fit and the higher quality joysticks giving a smoother, more precise flight feel.

The Take Away?

The take away from my Index controller experiments:

  • Exciting new SteamVR 2.0 input device
  • Interesting new interaction methods that need support from developers
  • Aperture Hands Lab and Moondust are great showcases for the controllers
  • Excellent tracking and no occlusion in bow or gun games
  • Uncomfortable “out the box” with fitting and material challenges
  • Boosters made a big difference even for medium-sized hands
  • Larger volume Boosters potentially a good fix for people with larger sized hands
  • Custom printed Boosters could unlock more fitting potential
  • Don’t always have to be strapped in, try moving your hands around.
  • Gamepad controllers still work better for some applications
  • Some applications won’t work without rebinding or modding, some not all. 
  • Make sure you buy new directly from Valve as you may need warranty support
  • Would like to see trackpads ditched and higher quality joysticks in a future version
  • Would like to see controllers come with Boosters in the box

It’s really down to developers to now implement Index controller support where appropriate, which of course depends on how many consumers purchase Index compared to the less expensive and easier to use Oculus Rift S and soon-to-tethered Quest.

Around the time this article gets published, 46,000 Index are reported to be sold since the Index launch on 28th and Index has already made a noticeable dent in the VR headset surveys on Steam which indicates a healthy level of activity.  

Hopefully we will see the best examples of Index controller support and amazing new interaction in Valve’s new VR title when it finally releases – said to be late 2019 by Valve, but of course subject as ever to Valvetime – they’ll release it when it’s done!

Thanks for reading! Rob Cole, immersivecomputing

Categories
ergonomics

Valve Index : Headset Ergonomics

valve index ergonomics

Originally published by Skarredghost in October 2019. Edited to correct my original spelling errors and some images updated. All images copyright of immersivecomputing.org unless otherwise stated.

Introduction by Tony @ Skarredghost:

“If you are interested in ergonomics in virtual reality, today is your lucky day. I host a guest post by Rob Cole, that will show you his journey in making his Valve Index more ergonomic, modding both the headset and the controllers so that they can accommodate perfectly the shape of his head and hands.

Rob first tried VR in 1991, and has become an enthusiast of the tech ever since. Because of his background in industrial design, he has always had a strong interest in the design and the ergonomics of the VR headsets. At Immersive Computing (see his Instagram account) he carries on this interest, exploring the technology always starting from the human perspective, putting the human at the centre of his experiments and analysis. This post is the result of such kind of experimentations on the Valve Index headset.”


June 28th was a key date this year for a group of Virtual Reality enthusiasts who received on launch day, the first delivery of the new “Valve Index” PCVR system.

As a member of this small group, who against the odds had managed to secure a pre-order on May 1st, mine arrived at 12.31 pm on the 28th leaving me with the afternoon for installation and my first session.

The excitement of opening a new VR kit cannot be underplayed, it’s like receiving something magical, but I kept cool and took some unboxing photographs to preserve the moment for posterity before the packaging got tatty and the controllers bruised from striking walls.

valve index box
Valve Index full kit in neat cardboard box

By early afternoon it was installed, base stations bolted high up, covering a useful 3.0 x 2.8m play space, generous for a domestic installation in London.

In preparation for Index’s arrival I’d already installed the “Aperture Hand Lab” and “Moon dust” applications so I could try out the finger tracking of the Index “Knuckles” controllers, which were plugged into cellphone wall chargers to bring them up to full charge.

It was now time to take a deep dive into Valve’s Index to see what it was all about and test out the 144hz mode, which I was confident could be properly explored by my PCVR rig using its overclocked 8086K processor and 2080Ti graphics card.

A long hot summer of RMA’s…

Valve box full kit
Lots of spares thanks to Steam support sorting my RMA’s

This article has been a while coming….2 headsets, 3 pairs of controllers and a right ear speaker since launch meant more time in meat space than I’d recommend to any VR enthusiast.  

Despite some frustration over time wasted and trips to courier depots, I gained a cool collection of Index boxes and unavailable spare parts including extra cabling and a spare facial interface; for one rare week I had 2 Index headsets (Indices!) sitting on my desk.

two valve index
Advanced replacement for my headset meant I had indices for a week

It was also uncharacteristically warm in the UK this Summer, so when Index was fully working it was confined to early 6-8am sessions before the day heated up. 

New product launches can be difficult with new components from suppliers not meeting agreed specifications, or new production line processes where small assembly mistakes can have big usability or quality of life impacts on the end user, sometimes requiring replacement through the RMA process.

As a small example, my launch headset arrived with the headset harness offset to one side due to improper assembly, which caused it to sit skewed on my head as the offset gap just got larger the further the headband was opened.  

After some communication with Valve, it was advised to force the ratchet mechanism by hand to try and balance the strap, which thankfully worked and did not seem to cause any permanent damage to the plastic internals.

Ratchet strap came from factory with offset spacing causing headset to sit twisted on head

The phrase “Early adopters always pay” has been proven right once again, but as active support is being provided (albeit slowly at times and with different results) and Valve’s manufacturing partners in the USA and China improve their Quality Assurance, we can move forward.

Downtime with reality can prove fruitful, so during the long hot summer of RMA’s I dove into the ergonomics and looked at the 3 key areas that were bothering me during my VR sessions:-

  1. Index Facial interface
  2. Index Controllers
  3. Index Ear Speakers

For this first article, we will concentrate on the Index Facial Interface; a later article will cover the Index Controllers and Index Ear Speakers.

Index Facial interface

Time to dive into valve’s new Index PCVR headset

Index arrived with a single, removable facial interface, fitted to match a full–width pad glued inside the rear of the headset harness. It looked great, with a premium fabric outer and a comfortable foam inner; something that pre-release reviewers had spoken about favourably.

In Valve’s own words,“The Face Gasket for the Valve Index Headset is made with anti-microbial fabric that is soft on the skin and ergonomically designed to distribute pressure evenly”.

valve index facial interface
Valve Index facial interfaces

The magnet attachment system was a neat idea, though perhaps a little understrength as it was too easy to accidentally knock the facial interface from the headset; the first time this happened to me caused a moment of panic that the magnet may have scratched the right lens, thankfully it hadn’t.

There wasn’t a different width interface or a spare interface provided, which puzzled me as the HTC Vive (a Valve collaboration) had shipped with both narrow and wide facial interfaces – the “wide” really a regular fit and the narrow for people with narrow faces. 

Interestingly, some digging around on the internet by Steam user “BOLL” showed a now archived Valve product webpage for the Index headset from 1st April listing:

   2 Face Gaskets (narrow and wide)

By April 30th he noticed the webpage had been edited to remove any mention of narrow and wide, leaving:

 Face Gasket

Not sure what happened during this period, if there were plans for narrow and wide that got cancelled, but at launch Index shipped with just one Face Gasket (or Facial Interface, if you prefer). 

Instead, there was a rear cushion provided in the box for smaller heads, a basic foam rubber piece which seemed at odds with the anti-microbial fabric used for the facial interface and rear harness pad. Perhaps a lastminute addition, and a welcome one to provide more fitting options, but also likely to trap heat and moisture against the occipital bone (rear of head) raising the in-headset temperature.

valve index rubber spacer
Rubber spacer provided with the Valve Index

I’d always used the wide facial interface on the Vive as I’d tried the narrow interface before without any success when I got my first Vive in early 2016. People have different width and shape faces so the provision of narrow and wide facial interfaces made sense to anyone with a basic understanding of ergonomics.

Looking closely, Index’s interface seemed to be slightly wider than the Vive narrow but considerably narrower than the Vive wide.

Having also used my Vive with thin 6mm face cushions and now struggling to fit my face properly into the somewhat narrow interface of the Index, I wasn’t impressed with the field of view which felt more like my Rift CV1.

The omission of a wide facial interface for Index seemed very strange considering the obvious effort Valve had spent improving the headset’s overall ergonomics and how important the facial interface is for correct fitting especially for such a precise headset.

I soon found that the “sweet spot” (optimum eye position, relative to lens) was similar to the Vive in that it was relatively small – demanding a precise headset fit to align properly. 

valve index sweet spot
In headset lens shot showing lens off axis (left) and on axis (right), demonstrating the importance of a good fit when using the Index

The incredible clarity that had been talked about in reviews is something I could see by removing the facial interface and holding the headset close to my face. This allowed me to determine the issue was not caused by the display system (I got great clarity with this method) but the physical interference of the narrower facial interface.

Fitting is best done with the harness lifted up and the headset held loosely against the face with one hand so the sweet spot for each eye can be aligned before holding the headset in place whilst tightening the top strap (weight bearing) and rear harness (stability) using the other hand.

As my previous article on ergonomics explained, the facial interface is the primary physical interface for a Virtual Reality headset, the secondary physical interface is the harness.

The headset’s facial interface and harness should ideally support the optimum position for the user in that headset and then “fade into the background” by not applying undue pressure nor cause skin irritation.

VR headsets require a good craniofacial fit to provide visual clarity and stereoscopy, for headset stability (especially during movement) and long session user comfort.

A good fit is very important when using a VR headset

The aim when designing wearable VR equipment is to make it ‘transparent’ to the user; remove any physiological barriers to immersion to enable users to achieve a strong sense of presence on a repeatable basis.

Unfortunately, in my case the facial interface just wasn’t compatible with my face, I was finding it difficult to get my eyes into the right position causing optical aberrations and mild eye strain.

The need for constant adjustment and overall discomfort was dramatically reducing my enjoyment of Index to the point where I considered selling it, but before taking any drastic action I started by looking carefully again at the facial interface to see what I could do.

After removing the facial interface from the headset, I held it against my face (as if wearing the headset) and noticed a sizeable gap between my forehead and the face cushion, large enough to put my middle finger in the gap. 

valve index face mask gap
The gap is very visible between foreground and cushion

I could reduce this gap by gently bending the plastic base plate against my head, but when the facial interface was clipped back into the headset there was no such movement.

Tightening the harness just pulled my face deeper against the foam without finding adequate support, I could feel the headset moving slightly sideways as the foam further deformed trying to accommodate the mismatch with my face. 

One side effect was a black shape (display edge) noticeably present in my left eye but not in my right eye, to prevent this intrusion I had to dial the eye relief further out, further reducing the field of view.

I could get the position almost right by really forcing the headset’s position on my face and manipulating the headset harness but any tether movement would cause a shift unless clamped so hard it started causing craniofacial discomfort (i.e. sore face and headache).

With a slightly larger left cheek (zygomatic) bone than my right, I noticed that every time I tightened the headset it moved left, moving my left eye further off the sweet spot.

All humans beings display asymmetry which is perfectly normal, in fact there are few if any humans with perfect symmetry, which is why computer generated characters with symmetrical faces have an eerie “uncanny valley” effect.

Uncanny valley effect in action (image by Creepy Girl)

From my ergonomics work with performance athletes, I have not yet met anyone with perfect symmetry as all of my clients required adjustments to their equipment to accommodate their natural asymmetry in an effort to improve performance and minimise the risk of injury.

We are all asymmetrical whether it’s our hands or feet being slightly different sizes, the very common trait of a leg length discrepancy, a larger ear or a dominant eye.  In everyday life, we learn to accommodate these discrepancies and rarely consider them (you might find one shoe is tighter than the other) but in more specialist situations like fitting a VR headset it can become a problem depending on the amount of asymmetry.

My accommodation for this width mismatch is typical, there is a tendency to offset to the dominant side whether it‘s a VR headset or bicycle saddle – with a wider facial interface my asymmetry is present but does not cause such a radical shift in position. 

Additionally, as a “sample size” person (medium everything) I’m certainly not an outlier in terms of size; this left me wondering if the Index’s interface did not fit my somewhat average sized face, what about everyone else? 

Searching the internet, nothing wider was yet available from the after market companies as Index had just been launched. The only product I could find coming soon was VR Cover’s soft cover, which just wraps over the existing Index facial interface actually reducing the width.

VR Cover’s soft fabric Index cover (image by VR Cover)

I reached out to Valve and was told “Steam support does not have any information on when or if a new gasket will be made available.

I reached out to VR Cover and was told: “The team is still exploring several solutions for the Valve Index, so I’m unable to confirm if this is being developed. However, I’ve passed your suggestion on to them.”

So I continue using the Index as various RMA play out, but continue to struggle with my fit, “chasing the sweet spot” with moments of success followed by constant adjustment. 

I was seeing huge potential in the Index marred by frustration at my failure to find a good fit and the face cushion was starting to degrade with foam compression and ripples appearing in the fabric, not surprising considering the facial mismatch I’m asking it to try and accommodate. 

A wide face cushion emerges

Soon though, there is news of CAD files for Index being released by Valve, which includes a facial interface base design suitable for 3D printing. Excitement grows, files are released, the modding community is energised. ‘Boosters’ are also featured in the file dump, but more on those later..

Valve Index CAD
Example of CAD file released by Valve (Image by Valve)

Within days, I find a modified face cushion base which has been widened and released by Anonymous Hermit under the Creative Commons license.

It’s on Thingiverse and I quickly used my smartphone to try some 3D printing suppliers in the UK with the cheapest quoting nearly £250 (!!) but then discover Ninja Prototype who have a longer lead time but only want $33 including shipping from their Chinese print shop; it’s looking promising, there is hope yet!

RMA continues for controllers with joysticks not clicking in all directions so I purchase an Xbox controller and spend VR time driving cars way too fast in Assetto Corsa, and hearing voices in my head during the mindbending trip that is Hellblade : Senua’s Sacrifice. 

This period of seated VR proves useful to start experimenting more with the fit without the constant tug of a headset cable threatening to pull the headset out of alignment. I try using it without the face cushion by stacking strips of soft Velcro fabric; crude but very promising as it confirms the headset can easily cater for a wider face with the right interface. I also have some ‘wow’ moments of optical clarity which confirm the potential. 

valve index ergonomics
Experiments with Velcro proved a wider facial interface could work

During the Steam summer sale, I learn Valve is giving me a load of credit on Steam at the end of the sale as a reward for the Index purchase. I get a free pack of Index face cushions and some VR games… thanks Mr. Gabe!

Now with 4 face cushions (1 left from a headset RMA) I am free to experiment, so I quickly strip the worn original down to see what’s inside, interesting to see no doubt, and I salvage the nose gasket from it as I have just received notification my 3D print is arriving this week from Ninja Prototype. 

FACIAL INTERFACE STRIP DOWN image
Valve Index facial interface strip down

Previous experience modifying headsets includes the original HTC Vive and Google’s original Daydream, so I check my Amazon account and quickly find some old orders for aftermarket face cushions and industrial strength Velcro I can use to secure the cushion to the 3D printed plastic base. 

Ninja Prototype deliver on time providing me with a very stealthy looking 3D printed facial interface base.

3D printed wide facial interface base by Ninja Prototype

I source slightly stronger N42 Neodymium magnets from Amazon and use an epoxy adhesive to bond each magnet firmly to its mounting turret, making sure they are leveled and centred. After the epoxy has cured I lift the print to the headset and it snaps into place with a satisfying click; the magnetic attachment is working as intended and now more resistant to accidental knocks. I carefully glue the nose gasket poached from the original Index facial interface in place using a special “gel” Cyanoacrylate which does not run.

valve index ergonomics
Gluing magnets on the new face mask

Turning my attention to the facial interface base, I wipe the surface with isopropyl alcohol, letting it evaporate in preparation for fixing the male-pattern Velcro that will be used to attach the aftermarket face cushion to the plastic base. Disposable nitrile workshop gloves are used at all times to prevent any skin oil or grease contaminating the bonding surfaces.

The first tricky part is cutting the Velcro to fit, which will require using as few pieces as possible to minimize any side shear from peeling the Velcro off when adjusting or removing the face cushion. Normally, the Velcro is a single piece, machine die-stamped using a cutting pattern, but I don’t have that luxury. 

To generate a cutting pattern I stick masking tape on the rear of the Velcro’s adhesive tape cover, so I can hold the Velcro against the base and use it as a template to draw a pencil outline. Adjusting for height, I eyeball it and carefully trim the Velcro with sharp scissors and check by placing each piece against the base. 

Making the mask…velcro fitting

I end up with 4 pieces, long strips top and bottom, small pieces left and right, I radius the corners to remove sharp corners which can get snagged and lifted when opening and closing Velcro attachments. 

The second tricky part is actually fitting the face cushion to the Velcro on the plastic base, its hard to centre and mount with equal spacing around the perimeter. Normally, facial interfaces and face cushions have a locating key to help with this, but we are freestyling here...a couple of attempts later it’s looking good. 

Wide facemask on the Valve Index

It’s now time for the “moment of truth” so I click the wide face cushion into place, give the lenses a quick clean, loosen the headset harness and lift the headset onto my face, just one word slips out of my mouth: “Wow!” 

Immediate thought is I’m back in a Vive but with more vertical FOV and slightly more horizontal, crisp edge to edge clarity and much higher resolution. The lenses and the display feel very different to the Vive Pro, it’s an impressive upgrade no doubt. I remove my new facial interface and do the “gap test” again, this time it‘s a great fit.

No annoying gap anymore, a good fit for my 59cm head

I hold the headset to my face with my left hand, before adjusting the harness; I try moving the headset around to find the right alignment to give each eye the best presentation. I carefully set the IPD and manipulate the eye relief adjuster until it looks and feels just right, using a variety of different scenes, the Real O Virtual test background and left/right eye checks.

Just as with my Vive, I need to rotate the headset slightly clockwise (from my POV) to raise the lens sweet spot to meet my left eye, like many humans my asymmetry includes one eye (my left) that sits higher than the other eye (right) on my face. 

With these adjustments set right, I notice the black shape is now missing from my left eye, and only appears equally on the edges of left and right eyes when winding the eye relief so far inwards the lens edges actually touch my eyebrows, so I wind out 2 clicks until there is no contact. 

To increase the FOV without the lenses hitting my eyebrows, I look at my face cushion, it’s slightly obscuring the edges of the eye box, so I try repositioning it on the plastic base. The HTC Vive had a smaller eye box so it‘s not surprising the after market cushion is not a perfect match for the Index’s larger plastic base.

I resort to cutting up an aftermarket face cushion, and manage to carefully fit it as 3 pieces, with some Velcro tape securing the cutting gaps on the rear of each piece.

Modifying the face cushion to increase visible FOV

Now it’s opened up the eye box, and I am getting the full-fat FOV that the Index can offer. It’ss also extremely comfortable with an equal level of gentle pressure across my face even when tightened. The headset has a stability I have not had before, requiring less tension on the harness to stay in place. The headset now offers good support from having the correct interface and has become much more comfortable with no need for constant adjustment.

I also quickly realise with the magnet mounting system that fine tuning of the fit is possible to further address asymmetry so I experiment with “stacking magnets”.

magnets valve index fit
Magnet stacking for fine tuning of Index face gasket

In addition to the strap pivot on the headset block, it’s also possible to also change the display plane angle relative to the eyeballs with this method as well as the rotation of the interface relative to the face. After many experiments, I found that 2 magnets on the top right and lower right mounts provides a very interesting result “cleaning up” the display in my right eye by taking away a fine slight fuzziness – I suspect caused by my eyes sitting at different depths in their orbits (eye sockets).

Its a very interesting process and adds a big advantage to Index for modders, it allows some adaption of asymmetry without resorting to expensive 3D scanning of the face to custom print a personal facial interface.

valve index wide face mask
Valve Index with wide face cushion about to be worn

Firing up SteamVR I spend hours in Valve’s “The Lab” at 144hz and with super-sampling cranked up to 2.5 (the advantage of using a 2080Ti GPU): I’m just marvelling at the clarity, small details and unreal sense of presence. Whilst kneeling to look at the sides of the arcade cabinet, the robot companion dog runs up to me and I am so startled I fall over (thankfully onto the rubber floor in my VR room).

Glorious presence in the Valve Index

Speaking of presence, with physical discomfort removed and the optical system now aligned, I soon realise the “secret sauce” Valve has baked into Index is the high frame rate and ultra low persistence; the virtual world has never looked and felt so real, with noticeable jumps between 90hz, 120hz and 144hz.

The Index is doing a great job of tricking my subconscious “lizard” brain that this is real, and I’m feeling a level of presence I’ve never felt in any other VR headset, it‘s hard to describe, it feels incredibly vivid both spatially and temporally.

Perhaps Norman Chan from Tested said it best, “I didn’t know you could get so much more out of 120, 144 hertz and feeling more present until I used the Index. With 120 and 144 hertz its like I’ve downed 2 cans of Coke and I’m hyper aware”.

My job here is done, the wider facial interface works and is letting me exploit Index to its true potential and revel in strong feelings of presence. However, I know from previous experience that cutting up face cushions is not a long term solution as they tend to degrade from having unsealed edges and cut foam, loose fabric, etc.

The standard Index interface (top) and the modded one, note the big difference in radius

The wide option certainly works, but the next step is producing a commercial version that can withstand daily use. Another angle would be a “gamer” version with slightly firmer padding and more moisture resistance designed to stand up to the rigours of long session, active room scale gaming and allow for quick cleaning.

For now I’ll keep using my wide prototype, enjoying my Index and experimenting with alternative face cushions. As can be seen in the image below with the eye relief wound all the way inwards, I now have equal balance between left and right sides of my face as witnessed by the equally placed sweat contact marks on the top of the lens surrounds. 

Sweat inside the Valve Index

This success of this interesting experiment (which I encourage other Index owners to try, even as a stop gap measure) leads to a simple question aimed at the manufacturers, specifically Valve but also the aftermarket companies:

“Please can you make a wider facial interface for the Index?”

Final note: Community reactions

Since starting to write this article, comments have appeared from Index users on the Valve Index Subreddit which demonstrates the demand: (of course, I have removed the usernames):

-“They also need to release wide face gaskets a.s.a.p…many users are out of luck with the stock gasket and have to print their own”.

-“My face can’t take any more”.

-“This is a very strange omission from the Index HMD. I mean the Vive had it. Does Valve think that all of the wide-face consumers don’t buy the Index? It really limits the fov due to keeping the lenses further away”.

-“Valve is expecting 3rd parts solutions to cover this, no one is even saying they are working on one.”

-“I have seven, wish they fit my face tho :/”

Thanks for reading! Rob Cole, immersive_computing


“I hope you enjoyed this deep dive in VR ergonomics. If it is the case, stay tuned for the second episode of the series and feel free to contact Rob to talk with him about ergonomics in VR! (Or contact me asking me to put you in touch with him…)”

Categories
ergonomics

The importance of ergonomics in VR

Originally published by Skarredghost in August 2018. Edited to correct my original spelling errors and some images updated.


Introduction by Tony @ Skarredghost

“I always say that most of my readers know VR far better than me. For sure this is the case of Rob Cole, that you surely know because he comments a lot on this and other VR blogs

Rob first tried VR in 1991, and has become an enthusiast of the tech ever since. Because of his background in industrial design, he has always had a strong interest in the design and the ergonomics of the VR headsets. 

At immersivecomputing (see his Instagram account) he carries on this interest, exploring the technology always starting from the human perspective, putting the human at the centre of his experiments and analysis.

In various comments he has written, he has highlighted his expertise regarding comfort and ergonomics of virtual reality headsets and how these characteristics are important to:

  • ensure the correct presentation of the virtual world to the user by ensuring optimum optical alignment
  • ensure the headset does not interfere with immersion by causing discomfort, even for longer duration sessions.

I found the topic very interesting, so I asked Rob to write something for me about it… and so, here you are with a very interesting post on VR ergonomics. Have a nice read!”


I’m at the technology store today in my local shopping mall because I want to get a new VR headset.

The latest model by “Virtual Dream” was released a few weeks ago, but I’ve had to wait until the end of the month for payday. I approach the sales assistant manning Virtual Dream’s in-store concession, he sees me coming and greets me with a friendly “Good morning!”

He’s already noticed I’m looking keenly at the new headset inside the display case to the right of his booth, and knows what I’m going to ask next.

“Have you got time to do a fitting?” I excitedly blurt out, and he nods enthusiastically before replying, “That would be a pleasure, however, it will take about twenty minutes to print your face mask if that works for you?” I tell him that’s ideal as I need to get some breakfast, so I’ll come back and pick up my headset once I’ve eaten. 

He asks how I’d like to pay, and I swipe my phone across his terminal, taking a third of my pay cheque. “Okay, if you can come around to the left side of my booth we can get you measured up”, he asks, “You might have seen this online but it’s pretty cool to try out in person” he adds.

On the counter of his booth is a small camera attached to a circular support frame, with a padded chin rest. He gestures for me to lean forward, and after I place my chin on the rest, he lowers the frame over the top of my head. “Please keep as still as possible, and make sure to keep your eyes closed” he suggests, before pressing a button on the rear of the camera. 

I hear a gentle whirring as the camera moves around my head, and less than ten seconds later, my 3D scan is captured, “That’s all done, we got a great capture here. Okay, your circumference is 58 cm so we recommend a medium, and your head shape is ideal for the Y-style harness”.

He picks up a tablet computer from the counter, and makes a few keypresses before turning back to me, “That’s all done, if you want to come back in about twenty minutes I’ll have it boxed and ready to collect.” As I walk away to find my breakfast, I hear the 3D printer starting to do its work.

“I returned my ******* because of the discomfort and bought a ****. The ******* didn’t fit properly and hurt my forehead after 30 min. Really wanted to keep the ******* but if I can’t wear it, there’s no point”.

“The *** was super uncomfortable for me and gave me a headache, whilst the original **** was very comfortable for me, especially once I got the ***”.

“I literally couldn’t go more than half an hour on the ****** without getting a nasty headache, so I can’t say if you will like either, you should try and demo one first before buying?”

“The **** just made my head hurt, and I found the controllers too small (I have large hands), but the **** fitted great and the controllers were way more comfortable.”

These are all real responses on a virtual reality forum after posters have asked: “Which headset is best?”…only the names have been changed to protect the innocent headsets. 

One person recommended headset X because they found it fitted them well, whilst headset Y was a poor fit that they found painful to use during longer gaming sessions.

A second person has replied with an answer that is the opposite; they thought headset Y was fantastic and spent hours using it, whilst headset X had them quickly reaching for the pain killers. So who is right?

Actually, both of them are right, based on their “headset fit”, or more specifically their “individual craniofacial anthropometry”, the technical term for the measurements that are used to describe the human head and face.

When you start looking closely at craniofacial anthropometry, you will see a wide range of variance and facial asymmetry, as there are few if any people with perfectly symmetrical faces.

And this is where things become more complicated when designing consumer equipment like virtual reality headsets, as there are few other products on the market that are worn so intimately against the face whilst secured to the head.

virtual reality headsets ergonomics

Other examples are scuba diving masks or full-face motorcycle helmets, although neither of these have the added complication of housing a head-mounted display that relies on a good fit for the correct optical presentation of the display to the eyes.

Historically, virtual reality systems were prohibitively expensive and were limited to being used in controlled conditions by a small number of researchers, scientists, and groups like astronauts. 

It was typical to customize headsets to suit these users, just as space suits were made to fit specific astronauts. Additionally, the headsets were used for task-specific work purposes, where comfort would take a back seat to the task in hand, and the duration of sessions was often short.

Image result for nasa vr
Astronaut training at Nasa used VR (image NASA)

However, following the release of consumer equipment like the HTC Vive, Oculus Rift, Sony PSVR and the various Mobile VR headsets, we now have a different situation with a much larger group of people (the general population) using virtual reality on a regular basis, for longer periods of time.

The larger this group of users, the more craniofacial variation is found, which has a direct impact on the quality of the virtual reality experience and whether users continue to use their headsets on a regular basis.

Oculus Rift CV1 has been used by many different people

A “good fit” is comfortable to wear and ensures that the optical presentation is correct to truly immerse the user in their virtual world.

A “bad fit” is uncomfortable (can be painful) and often causes a poor optical presentation which breaks immersion. A bad fit is simply a bad fit and not something that can just be easily adjusted away with headset straps or fiddling with the IPD (interpupillary distance) adjuster. If it doesn’t fit properly, it won’t ever fit properly, like a pair of ill-fitting shoes that don’t get better with time but continue to cause problems.

A bad fit can cause physical fatigue to the soft tissue of the face and hard bones of the head, creating stress which makes the experience unpleasant, and can contribute to a tendency towards motion sickness especially when combined with heat inside the headset.

A bad fit with poor optical alignment has a negative effect on the feeling of immersion and presence as it interferes with the suspension of disbelief, by constantly reminding the user they are wearing a headset – its hard to relax into your experience when one of your eyes is slightly out of focus, the stereoscopic effect is reduced or you have noticeable lens artefacts in one eye and not the other.

virtual reality headsets ergonomics
One Vive Focus worn by three different people

A number of headsets currently on the market have no IPD adjustment, or software-based IPD adjustment (with a fixed lens), neither of which give suitable optical alignment unless you are lucky enough to have the same IPD as the headset.

As an example of IPD variation, in men the 5th percentile for IPD is 58.5mm, the 50th percentile is 64.0mm and 95th percentile is 70.0mm, therefore the mean (average) is 64.0mm.

Using a headset with incorrect IPD can be “interesting” to say the least, and in my opinion why fixed IPD headsets should not be on sale as it’s detrimental to the user and their experience of VR unless lucky enough to have a similiar IPD.

The end goal when designing Virtual Reality equipment is “complete transparency” where it fits so well, you don’t notice you are wearing it; you simply relax into the virtual world with true immersion where you feel “present”.

As we start to see higher resolution displays coming to market, the notorious “screen door effect” will diminish, and more sophisticated lens designs will reduce or eliminate optical artifacts like “god rays”, meaning that good fit will become ever more important so as to not become a barrier to true immersion.

An interesting aspect of our ability to accommodate new experiences is a psychological trait called “bohemian adaption”, where something novel soon becomes the new normal, causing us to seek further novelty as we become dissatisfied with the normal.

A side effect of this is our ability to overlook flaws becomes diminished once novelty wears off, something many VR enthusiasts have experienced once they become accustomed to their equipment and start noticing the flaws, which start breaking immersion.

The headset that had the “wow!” factor soon become irritating because it puts pressure on the forehead, their left eye always seems a little out of focus, their left hand gets a cramp when using the controller, or they keep getting entangled in their tether. Good ergonomic design seems to reduce or eliminate these concerns, and good ergonomic design relies on good data.

virtual reality headsets ergonomics
One person wearing Rift CV1, PSVR and Daydream

When designing equipment, an “Ergonomist” (human factors design specialist) will look at anthropometric data. 

To suit the general population we’d look at a range from the 5th percentiles to the 95th percentiles of the dataset, which will then suit 90 percent of the population, and accept that people outside of these percentiles will not be catered for by that design.

This anthropometric data has been gained by measuring huge numbers of people over a number of decades through large studies by many organizations including those in the medical profession and the military.

As an example, a functional arm reach for “5 percentile female” is 73.5cm whilst for “95 percentile male” is 94.2cm. This difference in reach of over 20 centimeters is one example of the wide range seen in the human population, and variations are also present in craniofacial measurements.

As the old saying goes “You can please some of the people some of the time, but not all of the people all of the time”.

The aim is to please as many people as possible unless you are aiming your product at a specific group of people using a specific dataset, as there are different sets of anthropometric data to target different groups of consumers.

Some examples would be general datasets for Men, Women, Adults, Children, or more specific datasets, for example, Caucasian or Asian. Appropriate anthropometric data is a critical ingredient for good ergonomic design, but data can be limited for smaller population groups which have not been widely studied.

virtual reality headsets ergonomics
Each headset has its own design of facial interface

Companies like Oakley manufacture their sunglasses in “Regular” fit and “Asian” fit, as do a number of bicycle helmet manufacturers.

You will also see different “foot forms” used when designing shoes for a Germanic foot, Celtic foot or Greek foot, just to name a few of the different foot shapes found across the human population.

The companies that manufacture VR headsets choose a particular dataset (head model) when designing their headset, and will make design choices or compromises to try and suit the largest possible user base of their target market.

If you fall outside of this dataset, or have unusual features (as many of us actually do), you may find your headset is uncomfortable, slightly blurry or even painful to wear. This explains why a VR headset designed for the Asian consumer is often a poor fit for a Western consumer unless you actually better suit the fit of an Asian headset.

You can now start to understand why there are different opinions on VR headsets, and why it’s difficult to recommend a particular VR headset to a friend, colleague or stranger on the internet based on your own experience of wearing that headset.

A problem with the different “fits” that the current headsets have, is that you may want to choose a particular model based on its technical features, access to its content, or wish to support that company, but you might try or buy that headset only to find it doesn’t fit you properly.

Modifying Daydream to improve comfort and stability

Within each headset design, there is only a little that can be done to adjust fit, apart from some of the radical modifications people make. These tend to be “band-aid” fixes that only partially resolve fit issues to make that headset into something that can be tolerated, other fixes involve severe modifications that void the warranty which is less than ideal on an expensive headset that is only 2 months old. And sometimes the official upgrades can make the fit worse, for example, some Vive users bought the DAS only to find it much less comfortable than the original soft harness.

virtual reality headsets ergonomics
Three models of HTC Vive, three different form factors

You might have heard the word “ergonomics” when people discuss virtual reality headsets, such as “that headset had poor ergonomics!”. It’s a slight misuse of the word, as the definition of ergonomics is:-

“Ergonomics (or human factors) is the scientific discipline concerned with the understanding of interactions among humans and other elements of a system […] in order to optimize human well-being and overall system performance” (International Ergonomics Association)”.

Ergonomics is also known as “biotechnology”, “human engineering” or “human factors engineering” and has played an important role since the introduction of desktop computing in the office, where workers often spend hours doing repetitive tasks with a limited range of movement.

An Ergonomist is a specialist in the applied science of equipment design, intended to maximize productivity by reducing operator fatigue and discomfort.

As we move into the realm of immersive computing, the focus of the Ergonomist will shift from the desktop computing environment to the immersive computing environment which we access through virtual and augmented reality headsets.

This in itself presents a new set of challenges, ranging from equipment design to user interface design, and physical movement limitations inside virtual environments.

So what can be done to ensure headsets (and hand controllers, which we have not even mentioned) are comfortable? It’s a tricky problem to solve, as during the early adoption of consumer VR the development budgets are limited by the small size of the market.

This doesn’t leave much room to spend money on tackling difficult ergonomic challenges by offering a headset model with different “fits”, or providing much in the way of customizable or modular headset designs.

Improving comfort for the forehead

Magic Leap’s first AR headset has just come to market and shows some interesting thinking as its’ offered in two sizes, as well as each size coming with a “fit kit” offering a number of shaped pieces for the nose and the head padding.

This AR headset is different to VR headsets in that the waveguide technology does not allow for moveable displays to adjust IPD, so they’ve had to offer 2 headset sizes to accommodate users with a smaller IPD range and users with a larger IPD range.

However, if we run with this thinking, it could be possible for a manufacturer of VR headsets to offer different sizes, just as bicycle helmets are often available in small, medium and large sizes.

The current “one size fits all” model of the headset is a bad compromise, just as “one size fits all” cycle helmets rarely satisfy anyone, resulting in a loose fit or pressure points as the adjustment system cannot accommodate such a wide range of heads.

Each individual size of bicycle helmet has further adjustment using a ratcheting, radial harness system to really fine-tune the sizing; a medium cycle helmet will usually adjust from 55cm-59cm, as well as offering 3 volume settings using a rear vertical adjuster.

In addition to sizing options for VR headsets, different style of headset harnesses could attach to the same headset base to accommodate users with different shaped heads, especially to suit the occipital bone (the pointy ridge at the back of your head).

An additional design solution is to offer a user-specific, custom facial interface (face cushion). A custom facial interface helps accommodate the asymmetry that is found in our faces, and the direct influence this has on the optical presentation when wearing a headset, and user comfort.

Current headsets are designed so that the face is centred within the headset, and the IPD adjustment works off this premise so that an IPD set at 64mm has equal spacing of 32mm left and 32mm right.

But what happens when your face is not centred within the headset because of your facial asymmetry, and your left eye is actually further from your nose (34mm) than your right eye (30mm)?

Take an image of your face, and draw a vertical line straight down the centre, then measure the position (width) of each eye relative to this centre. Repeat the exercise by drawing a horizontal line across your face, and measure the position (height) of each eye relative to this line, the results are often surprising.

Further analysis shows variations between the depth of each eye within its socket (orbit), the volume of the cheekbones (zygomatic or malar bone), the shape of the forehead (frontal bone) around the brows and reports of 19 different nose shapes.

We also see optical variations with eye dominance or eye-specific refractive errors requiring specific adjustments (it’s not ideal to wear glasses inside a headset).

These physical variations can be accommodated by a custom face cushion, whilst optical variations can be catered for fitted prescription lenses and automatic IPD adjustment using eye tracking systems to cater for each eye individually. We are starting to see new prototype headsets coming to market with these automatic optical adjustments, which is very encouraging.

virtual reality headsets ergonomics
Hacking the Vive to customize it to the user’s face shape

Currently the aftermarket face cushions you can purchase for headsets like the Rift and Vive are offered in different thicknesses and types of material, but follow the same concept of the OE (original equipment) face cushions of a symmetrical shape, equally spaced for left and right.

These don’t allow any asymmetrical accommodation, which means one side may be more comfortable than the other, this is seen in “witness marks” as the bony facial structures compress the padding used in the cushion. What is required is a method of supplying a face cushion which properly fits that individual’s face, and ensures they align correctly with the optical display.

One solution is the emerging technology of 3D face scanning, for example, the Bellus3D Face Camera Pro which is plugged into an Android smartphone. This combines 2 proprietary state-of-the-art technologies that measure 500,000 3D points on the subject’s face creating a very accurate high-resolution face model in seconds.

We could take this face model and integrate it with a design model of the headset to generate a data file for a custom face cushion base. This could be 3D printed and layered with self-wicking, antibacterial materials to provide a skin-sensitive layer to prevent any irritation, reducing facial stress and heat build up. A layered approach with breathable memory foam  could ensure a supremely comfortable fit!

The same technology can also be used to scan the head to assist in selecting the correct size of the headset and correct style of headset harness to suit the head shape. Once installed in the headset, the custom face cushion and correct headset harness will give the user a truly customized fit addressing their craniofacial asymmetries, whilst eye tracking systems adjust IPD for asymmetry and depth focus on a per eye basis.

As described in my fictional story at the start of this article, in the near future we could see virtual reality and augmented reality headsets offering an individually customized fit that we believe is required to truly get the best from the experience.

virtual reality headsets ergonomics
A customized face cushion is a solution to improve the comfort of every VR user

VR enthusiasts often focus on technical specifications, obsessing over resolution, pixels-per-degree, refresh rates, tracking systems…perhaps forgetting the most important element of the equation is the human interface. As one colleague commented last year, the clue is in the name “headset”, a “set” you wear on your head.

As consumers, we can purchase custom footbeds for running and cycling shoes and heat molded ski boots, which have been successfully sold through retail outlets for a number of years. With some forward thinking this business model can be incorporated into headset sales, with consumers only needing a “one-time” capture which could be applied to whichever headset brand they purchase in the future, similar to the data your optician holds on your prescription.

We should look forward to the immense benefits to be gained from customizing our immersive computing headsets, to provide the best comfort and optimum optical presentation so we can relax in our virtual worlds, at least until its time for a bathroom break!

virtual reality headsets ergonomics
virtual reality headsets ergonomics
How the VR headset of the future should be to have great ergonomics

I really want to thank Rob for this very interesting post. I agree with him that now maybe it is a bit too early for VR companies to care about this since they are mostly focused in actually selling the devices… because the user base is still quite little. But later on, in the future, I think that it is room for these important improvements in ergonomics so that the user experience inside VR can be optimal. People that spend lots of hours in VR will be happy because of this.

Tony @ Skarredghost