Serious thread about finding the 'Root' Cause of Distortion

Whether or not Pimax can or cannot see Distortion, it is true that some members of the community have distortions in their headsets.

I personally didn’t see any on my 5K+ Loaner that came with other issues but no distortion.

This is a thread trying to look for commonalities since the cause might be previous headsets having bad QC, face shape, IPD, etc etc.

I think Pimax needs to just do an investigation and involve all members of the community that see distortion. Try to get as much info about it as possible. Maybe it really is fixed and the 8KXs backers and preorderers will see no distortion. Maybe it only affects people in an IPD range.

I’d rather see Pimax gather the community’s help to tackle this issue and benefit everyone. Of course in the future with eye tracking support this might really be a non-issue but we aren’t there yet.

For now if you experience Pimax Distortions just post your IPD/Headset and model no.

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In my case the differences in perceived distortion depends on whether or not Parallel Projections is enabled while using the Large FOV setting.

  • With Parallel Projections enabled on Large Field of View the distortion looks extremely fish eyed around the peripheral, and no distortion on Normal Field of View.
  • With Parallel Projections disabled on Large Field of View setting there is almost negligible but still visible distortion around the peripheral, and no distortion on Normal Field of View.

I’d love to see the distortion profile improved with Parallel Projections enabled, it is currently awful to use right now on the Large FOV setting.

My experiences are with the Pimax 8K using both the standard cloth strap and Vive DAS, and the distortion has existed in every version of PiTool I’ve used up until now.

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In my experience, there are 2 case.

  1. Center distortion like fishbowl, it caused by the thickness of cushion.
  2. Edge distortion, when I turn around and see some movement image at the edge, this caused by image of opposite lenses. Try to close one eye and turn around, or try to use finger to block by placing on the nose, I think someone has big nose and can block the image of other lenses. I don’t found this issue so much when I use the comfort kit because it has a light block at the nose which can block the image between lenses in the same time. Fruit ninja is a good game for test.
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My experience is the opposite of @bubbleball’s.

A thicker pad (22mm “Vive” one from AliExpress) and an extra layer of double-sided velcro in the top does the trick for me.

That is while using the DAS with the 3D-printable adapters which might might be what causes the need for extra padding in the top?

That said, there’s been a lot of improvements to the distortion profiles since I received my 5K+ (pre-order) and I might not even need the extra padding now? I think I noticed it first time when they introduced the 120Hz mode.

EDIT: If they do the “Pimax VR Experience” calibration part right, this will hopefully be (more or less) a thing of the past… Hopefully… :wink:

Another thing is the physical placement of the headset. I wore my Vive waaaay to low (the DAS should cup the lower part of the back of Your head to kinda lift the front/headset up a bit) for a very long time when I first received it as I didn’t know better. Doing that on the Pimax has a way bigger impact on the distortion due to the way the lenses are designed. When people complain about it resting on their noses I always think they’re wearing the headsets too low. They’re not supposed to rest on the nose (might of course be that it’s totally wrong to do that on my face shape, but by design it’s not supposed to rest on the nose)… :slight_smile:

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There is NO distortion.
This is going to come back and bite Pimax.


Just because you don’t see it, does not mean its not there.
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My initial 5K+ unit had distortion. It had another problem, which led me to RMA it.
The 5K+ I received then had no distortion.

No addons have been changed, no cushions, during this observation.

It’s probably an issue with tolerances during manufacturing of the lenses.

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Or placement of lenses since there wasn’t any automated calibration done on early headsets?

I hope they weren’t carved by hand… :smiley:

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Probably! At least that’s what I experienced. One 5K+ with distortion, one without. I didn’t change or mutate between the exchange. :slight_smile:

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Are You absolutely sure…?

NotSaying

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I think I need to call Mark, this observation thing isn’t going too well I fear

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It’s a shame how Pimax deals with these kind of issues.

Just as with the cracked housing. Claiming there are no cracks because “they have the real numbers”. How did they obtain those numbers? Did they visit every Pimax owner and check their headset themselves? Many people don’t even notice some small cracks. Did they send some survey to everyone? Most people certainly won’t RMA their headset because of some small cracks. You’d probably have to multiply the number of RMAs because of cracks by 100 to be in the right ball park of cracked headsets.

But back to topic: Distortion on the Pimax is very real. There is some distortion on any VR headset, not just Pimax. Many people don’t notice it, because they are focused on other things. It’s not the first thing you notice when you try out a headset and some people never notice it at all because their brains automatically ignore it (that’s a good thing). Asking people, especially the ones who’ve never used a Pimax headset before, if they can see distortion after 5min of usage, without even explaining what to look for in and what “distortion” can mean, is not a good benchmark for measuring if your headset produces lots of distortion.

Here’s a question for everyone, who doesn’t see any distortion at all (according to Pimax, the vast majority of people):
You look at some object in real life, preferably not a very close one. Then you start turning your head up, down, sideways, round movements etc. but keep focusing the object with your eyes. The object doesn’t change its shape at all. If it’s too close, it might change a bit, because of the different angles you’re looking at it.
Now do the same thing in a Pimax headset, for example, look at the moon in the Pimax home environment. A perfectly round circle. When you turn around your head, does it stay a perfectly round circle or does it become slightly oval / pulled apart / compressed depending on where on the headset it is being displayed?
Could also someone from Pimax, like @SweViver or @PimaxUSA do this and confirm if it’s always perfectly round to them or if it’s just something they don’t notice during normal usage?
This would be useful to find out, if it’s just an individual perception issue, or an issue with some Pimax headsets.

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I’m pretty sure it’s just difference in sensitivity to it:

  1. IPD has nothing to do with it. If you close 1 eye distortion is exactly the same. In fact I find it easier to really pinpoint it that way, since it’s really 1 iris to 1 lens, so that makes it easier to pinpoint which parts of the lens are the most problematic.
  2. If you remove the gasket+foam you can get the lenses extremely close to your eyes. So even people with bigger foreheads and more recessed eyes can simulate a small forehead + protruding eyes. In a 100% dark room you can then try everything from moving up down, left right, foreward backward and tilting. Yes it will affect the distortion but I can’t get it to a point where it’s 100% gone, no matter how long I try.

That just leaves me with sensitivity to the effect. Distortion is only seen when you A) move your head and B) look through the sides of the lens when doing so. Maybe some people do that more than others, maybe some people mainly just look through the center of the lens and don’t move their irises as much. Also, why is person A better at geometry than person B? Serious question. I think that’s a big part of it too. So in other words I think differences in how our brains process geometry is part of it too.

Either way I respect your efforts with this thread, I tried it too but after the video yesterday it’s 100% certain that Pimax’s official stance is denial instead of an intent to fix it. Even though all they’d need to do is send a PM to @lionel

It is what it is. I have given up hopes. We’ll need to wait till a competitor comes up with a high FoV headset with high resolution. But man honestly, that can take a while … StarVR would need to up the resolution but would they do that within 1 year after releasing their current headset? I highly doubt it. It’s sad.

Off course there are distortion and also very shaky world
i am glad i paid 300 dollars for it, i would be mad if i paid anymore than that.
i like my Pimax…because i got it, but i do believe is a cheap design with poor reliability, distortion and unstable picture.
Put headset on, take a reference point in horizon and move head up and down fast…

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Even with 1 eye, IPD does affect distortion I think, because it affects the position of your eye relative to the lenses/screen. If your eye is not correctly centered due to wrong IPD then it could cause more distortions.

I can see distortion on my 8K, but it is only at the top/bottom and left/right edges.
It does not affect me during normal gameplay and the immersion of wider FOV beats the distortion. (Whenever I try Vive again for example, the FOV seems ridiculous.) It can get distracting sometimes, but when I am immersed in a game I don’t notice it.

When I tried the 8K+ however, I noticed that there was almost no distortion at all. Top/bottom edge distortion seemed completely gone. I don’t believe anyone would have a problem with distortion in 8K+ if they saw the same picture as I did.

With a side by side test comparison it was obvious that my 8K had more distortion and the 8K+ had almost none.

This improvement may be a result of the smaller panels, new distortion profile, and/or the new comfort kit which places your eyes at the optimal distance and angle.

So I think people might want to wait and try the new 8KX with new comfort kit and face pads to see if the distortion is possibly greatly improved for them. I think this is why Kevin and Martin say that distortion isn’t a problem for maybe 9X% of people who try 8KX … because I think it has really been improved.

With 5K+/8K then yes, distortion is obviously a real problem for some people.

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Two things are needed for an investigation to be of any benefit.

  1. Properly controlled data sources. We are just now getting a precise IPD test, yielding some surprising results in the most basic use cases, so no, we don’t have this just yet.

  2. Resources to act on the investigation’s results. IIRC, the Pimax NOW event announced that automatic optical alignment at the factory is a new process for Pimax, so this is also just becoming available.

Now, for most users, and probably for Kevin (PimaxUSA) personally, in fact there is “no distortion in the 8kX”. What distortion remains is much less than any previous headset.

My guess is the automatic optical alignment and increased panel utilization has allowed Pimax to be more aggressive with distortion correction. If so, that cannot be backported, but will improve further with every future Pimax headset.

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An article from Doc-Ok

TLDR: The best distortion algorithm will change based on where you are looking (pupil location) to ensure proper geometry across the entire screen (requires eye-tracking).

If you don’t have eye-tracking, then the distortion algorithm should use the center of your eye. It won’t give proper results across the entire screen but the part you are looking at should be fairly good.

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