8KX High Res/FOV is Moot if the 3D Depth is Lacking

Pimax 8K Series
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I’ve owned most VR headsets and whilst I appreciated the wide FOV of the 8K, I’ve found there are more important elements to consider when in VR. One area that is seemingly overlooked on these forums is the 3D depth perception. Perhaps this isn’t noticable when playing games which force focus on close-up objects.

I noticed how the 8K was in comparison to other headsets like the Index and CV1 Rift when swapping between the two. The 8K felt more like a high-res 3D screen attached to the face with head tracking a kind of pseudo VR almost. You get used to it when that’s all you have to judge but when you then look at lower FOV headsets it becomes more apparent. Skyrim VR for example, those distant mountains look too close as if they are a wrap around image rather than far away.

I think the problem here is most people testing these headsets at events are focusing on the clarity and being blown by that. Looking at any edge distortions but then forgetting that objects in the distance don’t look realistically far away. This is really important for immersion.

When you first boot up Steam VR and you are in the black or white room with the white circular lines, this is a good test of the 3D depth. I am pretty sure it’s designed that way.

I am wondering now then, will the 8KX have better 3D depth than the 8K. Is this something Pimax are aware of and is this adjustable via Pitools software profile?

I recall messing with the IPD when using the 8K and it did produce more depth but that introduced a weird circular point in the centre of the view at odds with the rest of the screen.

Any thoughts on this from anyone?

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Paging @risa2000, this is his pet pieve with the Pimax HMDs and he has the know how to explain just why these issues are present.

From what I understood, it’s the canted displays combined with a lack of calibration as well as the lense technology used that end up providing a very small binocular overlap which in turns causes a lack of depth perception. Add to that the varying facial shapes of users and it’s a sh it show where some don’t even notice whereas others incur heavy eye strain.

I‘m thinking that the Comfort Kit + MAS can alleviate the fit issues, Pimax claim to have better calibration per unit as part of their production line and the fact that they apparently improved the lense distortion profile to account for the new (smaller) panels on the + and X could all contribute to an improvement in that area.

@mixedrealityTV, care to chime in on your impressions?

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I have had an eureka moment with my 8K when the software IPD option was introduced in Pitool.

I did a thing and suddenly I had 3D. It was only then I realized I was doing without the whole time. Or at least it wasn’t as natural before.

It made me rethink what 3D perception actually is. I mean, it’s a thing your brain does. It uses information like stereo images but also other clues, from experience the size of a certain object in front of you can produce a perception of distance when you’re convinced of the objects actual size, without stereo images. Like when an object is more than 300 meters away, there is no telling if it’s 300 or 400 meters away by stereo images. Your experience and logic however will have to take over. A lot of that is happening in the Pimax headsets I think.

When I tried some other headsets at the VR Days, like the Oculus Quest and Rifts, I immediately felt a difference of importance in this regard. Those headsets have it correctly done. There is an immediate sense of looking through a window. The Pimax did not give me this sense at first. Also the X and + I tried. But because I fixed that in pitool before, I am convinced I can fix it later with the X too. Hope I’m right.

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This is my sentiment also. You were using the headset and the brain accepts that as normal. Then when it is corrected there is a night and day difference. I wonder how many people are using these headsets and not realising that the 3D depth could be so much better for more realistic immersion.

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Cheers for your input!

This has me worried though. I think it was @risa2000 that said that tinkering with sw IPD can produce a 3D effect but at the cost of losing geometric ‚verity‘ which I understood to be the expected geometrical proportionality of the rendered entities.

That is to say it‘s a hack method which can achieve the improvement of one variable (3D perception) at the cost of other variables.

I do know it’s this very issue that had me switch to Index in the first place. Yes the FOV is smaller but everything just ‚feels right‘.

@PimaxUSA, care to chime in in this?

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This is exactly what happened when using the 8K for me. The 3D got better as the IPD was adjusted but there was a circular area in the centre of the view which seemed further away than the borders around it. Totally unusable like this.

Which is why I say pseudo VR because it really does just feel like a high res screen pressed against your face magnified by the lenses and with minimal 3D separation.

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Once I got my 5k+ dialled in correctly (IPD and vertical offset) and got it positioned right with a suitable foam; it became the headset with the best 3d depth and sense of presence for me, by a distance.

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you must have a faulty unit, with my 8k i could set scale and depht perfect with the offset settings without the circular point you mentioned. In comparison with wmr headsets i had and tried i could get the 3d not as perfect, for me it’s the difference to be in a room on the 8k and it looks like i’m in a room with wmr.

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A gamble everyone takes with Pimax products…it seems maybe a number of people have or had faulty units perhaps without knowing.

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Have you used an Index headset before? Index seems to have the best world-scale compared to all other headsets. There is definitely a smaller 3d depth sweet spot on Pimax headsets due to less binocular overlap compared to other devices.

I wonder what makes Index so much better in this regard with it having better world scale and more binocular overlap. Index also has canted displays as well, Maybe Pimax displays need to be canted less for more binocular overlap?

@jojon put the binocular overlap and incorrect world scale issues Pimax headsets have into words very well. It likely is caused by the design of the current lenses. But as for what he mentioned about glare even index has the yellow glare/god rays issue worse than the OG Vive despite the fact Index has fused fresnel lenses, developers really need to find a better alternative to fresnel lenses.

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yes it could well be, i hope the automatic callibration method Pimax use now will be more consistent.
(edit)I’m optimistic get the impression that they have tackeled the problems, i remember in the begining there where a lot of complaints about the optics and that faded away over time.

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No i haven’t tried the Index, i have heard this from other people too. I did have the og Vive, wich seamed right, is the Index better you think?

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I ve noticed something is off with 3d movie compared to all the other hmd I tried.
But I can’t say for sure if it comes from the design of the hmd or problems figuring out the correct placement, correct IPD…

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Really ? Never heard about that.

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Perhaps pimax might need a 3d adjustment effect like BinoPlayer has that can even make 2d video 3d.

I’d need to once home take a better look at the effect your describing. But do remember some games do have a decent depth effect so it could also be what you said… Standard FoV headsets have restricted view point & as a result the depth may feel more natural vs the Wide Fov.

We should be able to test to some degree using Small FoV mode. Some have said they have xp improved 3d effect with ipd soft adjustments. But could also be a placebo effect.

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Quite possibly. However it could be also a greater sensitivity to 3d effect. Much like @mixedrealityTV had a sensitivity that allowed him to perceive the 8k wobble that most don’t see.

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Hmmm I wouldn’t know how to test / compare if I’ve seen ‘true 3D VR’ or not.

I have only tried a Lenovo Explorer and Pimax 5k+ (and a Rift for 5 mins if that counts) - none of them made any 3D differences obvious, but how would I know if they are all set up right / wrong? They all felt good to me…

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Keep in mind the index may have the 3d world scale done right. But all restricted FoV headsets will have more 3d overlap due to the fov being small. Sure maybe pimax could use a larger overlap than what it has.

But I suspect it’s more the 3d effect that maybe is what needs to be improved.

Lenses will not improve 3d effect if the rendered images are not rendered without proper 3d effect. Paralax is off.

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You will have 3d. But think of it as a movie filmed in 3d vs one that was converted to 3d.

This is more of what Rob is describing as I understand.

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Yes the Index displays are canted and also require parallel projections which is hard coded to enabled in SteamVR on all games with no settings option to turn it off. 5 degrees vs 10 degrees on Pimax headsets.
https://www.reddit.com/r/ValveIndex/comments/bkg03u/valve_index_displays_are_angled_to_increase_field/?utm_source=amp&utm_medium=&utm_content=post_body

Well that’s the interesting thing, there is definitely a more 1:1 scale world view in the index.
Since the index displays are also canted, but at a lesser angle compared to Pimax, I think that the cause for Pimax not having as good world scale and not enough “3d” effect might be the fact the displays could be canted 5 degrees too much which reduces binocular overlap.

That and/or the Pimax lenses cause the incorrect world scale/distortion and lack of 3d due to not enough area of binocular overlap, because we’ve seen XTAL achieve a distortionless wide fov. Minimal glare and distortion and better binocular overlap can likely be achieved with a different lens type.

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