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How To Fit HTC Vive

April 19, 2016 | fitting vive htc ipd eye-relief disability vision
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General Notes

Fitting the Vive properly is essential to the experience, and it is very much not obvious how to do this as scant instructions are provided. However, your goal is simple: Each lens has a very small sweet spot of clear vision. Your goal is to line up the pupils of your left and right eye with the left and right sweet spots of the lens precisely.

The exact centers of those lenses are your targets.

I'm going to go over this in detail because it is vital you get it right. It is possible that some of the reviewers reporting discomfort or blurriness have not taken the time to get the proper fit. It’s natural to just want to start playing, but you’ll be a lot happier if you take the time to get a good fit. Also once you start playing some of the better content, you aren’t going to want to stop and take time out to work on fitting, so do it first off, then enjoy.

If you are concerned about wearing glasses or contacts, this is all still relevant, but you may want to check out the report on wearing glasses and contacts with the Vive as well. There are also several other reports on improving your Vive experience here. It is very important, as part of fitting your overall Vive system, to change your controller wrist straps.

IPD

Let's take an easy one to explain first. Your eyes and therefore your pupils are at a certain distance from each other determined by the size of your head and how close or far apart your eyes are in your face. This is called your inter-pupillary distance (IPD). Everyone's distance is unique, but generally falls within a certain range. There's a further complication: When you look at things close up, your eyeballs rotate inward toward your nose, which changes the distance between your pupils.

I’ll describe some manual ways to do this, but the easiest way to find out your IPD is to go to a glasses store. Any competent glasses store will be able to measure your IPD with a little visor you hold up to your face.

To do it manually, some people recommend a procedure where you take a ruler and place it flat across your nose at eye level. Close one eye, and looking straight ahead (not inward) with the open eye *past* the ruler as if you were looking at a far away object, mark the spot on the ruler that is directly in the middle of the pupil of your eye. Then, without moving the ruler, do the same thing with the opposite eye. Subtract the smaller from the larger to get the distance and you have your IPD. Hopefully you have a ruler with millimeter markings. Otherwise, you will have to convert from inches to millimeters.

It's very important to do this with the other eye closed on each measurement because if you have both eyes open, your eyes will turn inward to focus, decreasing the measurable IPD, and you’ll be imprecise on the marking because both eyes are competing to find the mark from different angles.

My caution is that when I tried this, I was 6mm off my actual IPD measured by the next procedure I will describe, which worked much better in the Vive. This procedure depends on having a pair of digital calipers handy like these. Do the same procedure as with the ruler, except put the points of the caliper arms in the center of each pupil. Now, obviously, I’m not suggesting you actually touch your eye with the points of the caliper arms, just sight through each point with the respective eye. If you poke your eyes out with digital calipers, that’s on you.

However you go about it, memorize (yes, memorize, because writing it down isn’t going to help you later as you will see) your IPD in millimeters and go on to the next step.

Eye Relief

The next thing we need to do is establish how close you can get your face to the lenses. The rule is simple: As close as possible for the widest field of view in VR without any part of your face, eyelashes, or glasses touching the lenses inside the headset.

On each side of the Vive where the straps attach are little gray wheels. Pull them both out from the headset and see that they rotate. You will see that the mask on that side will pull away or move in towards the front of the headset when you rotate the wheel on that side. Rotate them both so the mask is as far in as it will go, creating the minimum amount of space between the front of the head set and the foam mask.

Gray wheels locked in; eye relief adjusted all the way in (only one tick mark visible).

Let all three velcroed straps go completely – the two sides and the one on top. Now, holding the straps out of the way with one hand, use the other hand to bring the mask slowly towards you until it is firmly pressed against your face. If at any time any part of your face, eyelashes, or glasses touches the lenses, stop, increase the eye relief on both sides using the little gray side wheels, and try again.

Once you are able to press your face firmly against the face mask with nothing touching, your eye relief is set. Push the little gray knobs back in towards the headset so they no longer rotate and proceed to the next step.

Strapping In

The next step is very important and is the reason some people are experiencing discomfort and blurriness. Examine the point at where all the straps come together away from the headset. Notice that they form a small bowl pointed towards the headset.

Bowl shape at back needs to grip the back of your skull like an Alien facehugger.

Reach up and cup the back of your head with your palm. Not the top of your head, the back of your head. This is where the small bowl needs to go to help distribute the weight of the headset over your entire head, align it properly for best clarity, and keep the headset from moving as you look around.

Those of you with long hair should, before strapping in, get a scrunchy and get your hair managed as there are a lot of cables, straps, and velcro about to get into engagement proximity with your hair. If you are bald, you simply evolved for VR.

With the straps let out all the way and the three strand wire slacked between the top sleeve and last sleeve so the top strap can stretch out all the way (check this each time you put the headset on), hold the headset to your face firmly and bring the bowl all the way across the top of your head. Adjust the top strap so the bowl is in a similar place to where you put your palm. If you do this right, the whole headset should be able to easily hang at eye level with just the top strap secured. When you put it on and take it off in the future, you will not have to adjust the top strap, just the side straps.

Once you have that set, adjust the two side straps so that the face mask is secure against your face. You’ll be able to see a little bit of light if you look down past your nose. If there is a lot of light, your mask is too high.

Adjusting Headphones

You can plug in your own headphones, but I like the earbuds that come with the Vive and everyone will have those, so I will describe the best way to get those fitted here. Note that, in the Vive package, there are alternate sized tips. Try them out to see which gets the best fit. You’ll want a pretty secure fit since your head will be moving around, so if they are easily falling out, use the bigger size. The headphones are a little strange because the buds come out at a diagonal from the overall headphone housing, so experiment with putting them in with your eyes closed without the headset on. You need to be able to this effectively blind when you have the headset on in case they get knocked out.

An important tip for headphone comfort is to make sure you do not run the headphone cord all the way through the velcro strap sleeves like the 3-strand connection cord. Instead, only run it through the sleeve at the top of your head, not through the sleeve by what I am calling the strap bowl. If you run the headphone cable all the way through, the loose earbuds cable will not be long enough and movements of your head will keep pulling the earbuds out of your ears. You want the the right and left earbud cable to come down directly from the top of your head.

Great little earbuds, best if headset cable set up as depicted in eye relief photo.

I've actually found it easist to disconnect the head phones from the headset, put them in your ears, put the headset on and fully adjust it, and then bring the cable on the top of the headset down and attach it to the earbud connection cable dangling at your neck. Making the one connection seems easier than pulling and tugging at the headphone cables while you are blind. Also doing the same in reverse and getting into this habit means you can take the headset off temporarily while keeping the earbuds in and then resume without having to reseat the buds.

One final tip is that the right channel has a small plastic tab in the cable leading to the earbud. You should feel for this when you are inserting or reinserting the earbuds with the headset on so you have the correct channel in your right and left ear respectively. Getting this mixed up will be very confusing and could lead to nausea.

Setting IPD

The next steps must be performed with the headset on. Get through the tutorial and get to the VR load in screen where you are just standing around in an empty environment. I like to pick something in the distance to can use to test the sharpness of vision, which I do for each eye every time I put the Vive on.

The Vive has a knob on the right hand side, which adjusts the distance of the lenses from each other and the center of the mask to match your IPD. Reach up with your right hand and rotate the IPD knob. After a little bit, you’ll see in the bottom of your field of view a dialog window indicating the current IPD setting in millimeters. It sometimes takes awhile for this to come up, so keep twiddling for the knob for several seconds if you dont' see anything. Adjust this to the IPD you measured earlier.

Gaining Clarity

Next, focus on a distant object on the horizon. With your eyes centered and your head directly facing the spot, move your face mask around a little side to side and up and down with one eye closed and then the other so that both eyes are as sharp as they can be. You may have to let the side straps out a bit to do this and even rotate or twist the headset a little so that it seems like the mask is a little higher on one side or the other.

Once you find the exact positioning that works the best for both eyes, adjust and tighten the straps to lock this fit in place. With the straps all set, verify that the final fit is giving you good clarity in both eyes individually and proceed into VR. You don’t have to really crank the headset in against your face, just enough to keep it from moving when you make normal head movements.

I suggest quickly running through this final little distant object check exercise every time you start a session. It really improves the experience when you have your fitting dialed in just right. Make this easy by, in VR, going to the system menu, selecting settings at lower right, selecting in-system settings, and changing the background image something that has something in the distance you can focus on. Then you will have a known reference available whenever you are not in a VR app.

Final Notes

At this point, you should have the perfect fit. Ideally, you’ll be able to see the screen door effect pretty clearly (black space between individual pixels) if you focus on it on a distant object. For those concerned about screen door effect, it’s not bad and only really noticeable if you deliberately focus on it.

Also, you will have to train yourself to look with your head instead of moving your eyes to look at things because everything outside of the center sweet spot of each eye is going to be blurry. That’s just the limitation of current technology and lenses. You'll probably never get fully used to it, but it gets a little better as you spend more time in VR and become conscious of how your head movements affect clarity.

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