Playing with Face Foam on Cowling of Pimax Vision 8kX (surprising results)

Since the beginning of using my Pimax 8k and now recently the 8kX, in the past i have often claimed to never have experienced distortion or oddness of picture rendered in either hmd while playing my favorite games.

To be perfectly honest, when someone described this strangeness i was perplexed.

Knowing things like finding correct ipd making adjustments both up and down side to side could improve sweet spot and clarity i remained skeptical when others described distortion wobble fisheye or other, until today that is.

Desiring to check if using a thinner face foam would increase my FOV in the Pimax 8kX, i took out the original foam deciding to try whatever i had lying around, that turned out to be an old Gear VR face cushion from back in the day.

After applying and then entering SkyrimVR i couldn’t have been more shocked by what i experienced, all the descriptions i had heard described earlier were evident now and apparantly in full bloom, and at that moment i thought what the… this is not good, i hope this is not permenant but the fear crossed my mind for a moment untill i played around some more wandering on the path in SkyrimVR while making every adjustment to the hmd i could think of positionally.

Then to my relief i reached behind to adjust the ratchet mechanism by backing it out ever so slightly and i was back it was a miracle the game world no longer seemed distorted the fishbowl and odd distortions were completely gone, what a relief and for me a strange discovery for me so late in the game.

So from my experience today i hope that others will consider this lens to eye adjustment distance more critical to a better experience in their Pimax HMD’s.

Here are a couple images from today of my Pimax 8k face cushion and the Pimax 8kX alteration also from today.

I guess i just got luck on finding the perfect distance early on with both face cushion mods.


Pimax 8k


Pimax 8kX

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When I first got the 5k+ I had some fishbowl effect but I got to my lens-eye sweet spot by changing to a thinner face foam. 16mm VRCover for Vive Pro for those who wanna know…

Anyhow! What everyone can do to explore this freely is to remove the face foam completely and just hold the hmd and use the fingers/hands as a connecting support to find the distance, tilt and position that best works with their eyes. Also adjusting IPD distances and repeating the process, because moving closer or farther to the lenses affects the optimal IPD distance.

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So are you saying you had less distortions with the thicker face foam than with the thinner one?

In a nut shell what i’m saying is that my eyes were to close to the lens and once i adjusted them to the proper distance no longer did i experience that strange number of aberrations. Thin foam or thick foam its the distance that matters and is relative to a persons face shape.

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At these prices hmd’s should have an eye relief adjuster of some kind

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Some of us have been trying to say that the distance between HMD and face is crucial all along, as the depth of which the eyeballs are located relative to our foreheads and chins is different.

Again, Pimax should just have included either three thicknesses of the foam or a single thin one and “spacers” (double-sided velcro pieces).

Would have been cheap and spared them a lot of bad publicity… :+1::wink:

Oh, and instructions on what they’re there for… :grin:

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I did have just that experience with the comfy and 5k+
Thinner foam = no-go.

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Same here on 5K+. 22mm Vive PU leather/foam + one layer of double-sided velcro on the top part of the (og) cowling.

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eyes-illustration

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today I was testing 262 and XR which I didn’t use for weeks, I recalibrated ipd to 64 and it was minimum mechanically possible, also cut Velcro’s and adjusted tilting, oh what a pleasure to have both eyes in focus, my 5k+ has worse lenses but here it’s perfect, so huge sweet spot, I don’t see any distortions at all only if hmd isn’t aligned, I wish they have fixed that dull problem which is still relevant. If resolution and colors would be on par with vive pro it would be my favorite hmd ._.

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Have you tried increasing the Contrast in PiTool? You might also want to reduce Brightness, so contrast doesn’t overwhelm the bright colors. On my 8K, I like Contrast = +1 and Brightness = -1, but if you want really saturated colors, you can try higher Contrast values.

For sure I tried, it makes image brighter but crushes colors, it’s not the way this problem with dulled imaged is supposed to be solved

The brightness = -1 is to help reduce the crushed colors. Anyway, this is off-topic, so I’ll stop now.

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I had exactly the same experience. I realise now I lucked out by doubling the thickness of the 5k+ foam and never had any fishbowl effects, swim, or distortion.

But at one point I tried to reset my comfort setup and tried to use the standard thickness, and it was horrific. Then I felt what others had been experiencing with the eyes to lens distance set incorrectly.

Totally agree with others, swapping foam thicknesses is a solution, but a basic one - there will always be someone who needs a custom distance to make a Pimax headset work. An Index-style adjustable dial and lens housing is the proper solution.

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Would be nice if Pimax did - some of us have been harping on about how crucial that adjustment is, especially given the canted optics, since the kickstarter (EDIT: I.e. long before the product was finalised).

At least we now, eventually, are getting an extra pad, with different thickness, although it actually sounds more like they did that to deal with the “cutouts for eyeglasses arms, or not” matter, than for having given a second’s thought to Z adjustment.

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Agreed. Sometimes it seems that Pimax’s communication issues include selected deafness. I’ve continued to emphasize how important the pad thickness is, given that the headset itself has no distance-to-eyes adjustment. Personally, I think they should include 3 thicknesses of foam (and I have told them so, several times).

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Pimax headsets, due to canted lenses, have complex and almost weird interactions with these sort of geometric adjustments, which makes these sort of features far more important than for any other VR headsets. From pupil, through lens center, to display center, must be aligned, at the most readability-critical depth, and changing anything - even lens-to-eyes distance by just half a millimeter - will throw that off. The hardest part is that without a lot of VR experience, it can be extremely challenging to recognize when things are starting to work right before moving on to try something else less optimal.

A month or so ago, I would not have understood exactly how much of a difference this makes. Having seen the basic IPD tester really changes things.

Ultimately, the best solution would be curved displays along with some very complex shaping, that could only be achieved with optical simulation driven CAD modeling and a completely specialized lens polishing/testing machine.

In the meantime…

More thicknesses of foam, if not other varieties of foam, is a better way to go than mechanical adjusters. In fact, it would be great to see assorted kits of foam for Pimax headsets, or even a much wider variety of aftermarket products.

On a somewhat similar note, on my latest 3D printer design, I am finding that a flat surface and shims is a far better way to adjust limit switches, than the adjustment screws which can wobble by multiple first layer heights.

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