GUIDE how to achieve Perfect Real View with Pimax IPD compensation

pitool
fix-guide
vr-academy

#1

Hi everybody again!

I was working with this incredible tool (IPD offset) in the new beta of Pitool, and my Pimax mods… and as you know, I made a lot of tests before.

Long time ago I said to @anon84525399 that we need IPD by software to compensate the stereoscopic distance measure in Pimax. Because, is not the same as IPD, but it’s the same xD. Thanks @Sean.Huang for implementing it.

In human vision, IPD is the distance of our eyes, and Stereoscopic Distance Measure is the same. But in VR is different.

You can view more information here:
https://en.wikipedia.org/wiki/Stereoscopic_depth_rendition

As you can see, in VR the software and hardware need to relate both factors. IPD and Stereoscopic virtual measure (or distance). In this way we can achieve a R=1 (read the wiki xD).

BUT TL;DR:

FAST GUIDE!

First, we need to adjust our Stereoscopic Virtual Measure with the IPD Offset. We need a real object in the same place that a virtual object. Is better if you can place it at 3 meters of you. I did it in SteamVR, because it’s very easy.

Now, you need to stare to this object, and put on and take off very fast your Pimax. If when you interchange real object with the VR placed one… you see double… then, your IPD offset is set bad.

The best way is to change it by 2 steps. From -10 to 10. And if you feel that the cross eye change the direction… then you are near your real Stereoscopic Measure.

You will know what is your perfect Stereoscopic Measure, because when you move ALL the hardware IPD from one side to the other… you will see that real object and virtual object are sync, without double vision. Your eyes didn’t need to focus it again.

That the reason why there are who say “For me all IPDs are good!”. Because the IPD offset for they are 0.

In my case IPD Offset is -0.5. In this vaule, I can use ALL IPD by hardware, and the object is focused.

BUT! Now we need to adjust IPD by hardware. Because the lenses change the distortion across the image, and can modify the apparance of the objects, and cause eye strain.

For me, I prefer a lower number. Why? Because if the two sweetspot are very close, then you can read closer too. For me IPD 63.2 is perfect to read at 20cm of distance in VR.

My real IPD FYI is 66.9 (near) and 69 (far).

One more thing… if you change the foam, distance between your eyes (xD) or distance with your eyes and the lens… you need to do it again.

Bye! And Thank y ou for reading :stuck_out_tongue:


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#2

Thanks for your work Yen, Pimax should implement some kind of tool to simplify this task.


#3

Yes! I was thinking about this… something like the ROV test but for IPD and Stereoscopic measure hehe.


#4

Good job Yen and good idea Tristanc! :+1:


#5

Thanks! Finally I found that the IPD hardware in SteamVR is 63.2 and in the games is 64.5. I don’t know why… hehe

But the difference is huge! I can use the HMD for hours and my eyes feel sooooo natural.


#6

Awesome info & How to. Added to Pitool Downloads & Table of Content Wiki. Will add to Getting started faq later.

:beers::sunglasses::+1::sparkles: explains a lot on why some have eye strain.


#7

@oscar_rov @knob2001 are the folks your looking to poke. :beers::sunglasses::+1::sparkles:

@sjefdeklerk you maybe interested in this as well.


#8

And @risa2000


#9

Yes! I know @oscar_rov hahaha I use ROV test everyday haha more than SteamVR xD


#10

Sorry, what is ROV test and where I can get one?


#11

In SteamVR is one environment to test glare, colors, etc :slight_smile:


#12

Cheers, I’ll look it up


#13

remind me again why this is necessary


#14

If Pimax comes up with an easier method like Oculus Rift’s IPD adjustment graphical UI that would be the best.


#15

Sounds good, but how can we place a virtual object 3 meters directly in front of us in Steam VR?


#16

@neelrocker created an Oculus like ipd setting.


#17

The best way is simply teletransport yourself where is the virtual object and then walking 3 meters. But you need all this space hahah

Or you can use the ROV test, for instance, and move the ball.

In a game, you can do that too. The problem is that SteamVR has different level scale than games. Why? I don’t know. But I notice that long time ago with Vive.


#18

I would assume it’s best to start by setting the center of the lenses to the same distance as your pupils (how I did it) and then set the stereo offset from there.

Here’s some tips and apps for measuring your IPD: https://www.reddit.com/r/Pimax/wiki/faq#wiki_how_can_i_find_my_correct_ipd_.28interpupillary_distance.29_number.3F


#19

So you too have your IPD adjusted way lower than what it should be, and we have similar actual IPD numbers. My real numbers are Close 67.5 and Far 70, and I have mine set to 62 in the HMD with a -.5 offset too.


#20

I assume you did not see my posts on this topic. In the first I explain why the distance between lenses (centers) is bigger than the IPD value the headset shows (Some thoughts on the IPD discrepancy) and in the second I explain how the perspective projection (angular verity) is screwed up when you set the lenses closer than they should be (Clarifying Near IPD x Distant IPD confusion).

What you advertise here and on the reddit as a method for setting up an IPD is a myth perpetuated on this forum all the time = that in order to have an IPD set correctly, one must see a clear image in both eyes (when focusing on the same distant virtual spot). My second post above explains why it cannot work this way.

On top of that, using the fixed image, (which is rendered this way Pimax native projection and pre-lens warp transformation) introduces another false indication as it seems to project the image at the plane which is at infinity.

While there are people who seem to prefer to sacrify the angular verity in favor of a clear image (as you do), such setting can lead to other issues (as severe as the ones related to blurry images) and I would definitely not promote it as a solution to the problem, without giving the explanations of the consequences I made above and a big disclaimer.

Here are my two recent posts, why I believe that the IPD setting is a tricky subject, which does not have easy and reproducible solution. ([Pimax Response Required] Is there an official solution for eyestrain and IPD issues in the works?), (Eyestrain discussion / Problems and Solutions).