3D headaches - Page 2

First person perspective in video games can give me a strain in my stomach and eyes, especially if I'm watching someone else play. Almost the same as when I try to read in a car (with someone else driving. If I do that while driving myself it is even worse I think these are similar phenomena to other people's complaints about 3D - especially 3D that shows a lot of moving around. So I think 3D has the same prospects for popularity as video games and automobiles.

And re the focus debate. It is not that anything is out of focus. The article cited by the OP mentioned the fact that any images delivered on a flat surface like a tv or movie screen always require the viewers to maintain the focus of their eyes on the screen. But if they are watching a 3D movie and viewing an image that appears to be say in front of the screen, they have to converge their eyes, so there is a little bit of mismatch between the distance where the eyes converge and the distance where the eyes focus.

It is not something we ever do in the real world, where our eyes pretty much automatically change focus to match the distance that our eyes are converging upon. In the movie theater, we must inhibit that automatic re-focusing the whole time we are scanning things up close and further away. We don't know if that does anything to comfort, but it conceivably could.

The "accommodation vs convergence" paradox can indeed cause headaches in a few people. The paradox can be made less stressful on the eyes and mind by making careful choices in presentation.

It's not something we're likely to see completely resolved without some sort of multi/variable focal plane technology.

http://spie.org/x41184.xml?ArticleID=x41184

perhaps Icester would like to respond to this since he apologetically accused one poster of talking total crap.

I read somewhere 2 out of 3 people are stupid.

So if you look to the person on your left and don't see stupid. Look to the person on your right and don't see stupid. Well....

Yes,
it is still crap as it totally ignores human eye's DOF.
None of the hypothetical situations used in studies represent real life situation where people view 3D on their 3D screens.
For example, if a person is sitting 5 feet away from screen and he converges on object that is 6 feet away he sees it with the same accommodation quality as if he was converging at 5 feet on the surface of the screen.
It is due to sufficient DOF (depth of field) which makes all objects in front of behind convergent point appear in focus.


Mathew Orman

If the screen is 30 feet away and the object being to be converged is 2 feet away (seen in many theater presentations with pop-out effects), is the human eye's DOF sufficient?

What of a computer monitor only 2 feet away with an object in the far distance with near parallel convergence (infinity). How well does our DOF handle that?

As far as I can tell the answer is to just avoid the above scenarios... Or present an accommodation-convergence paradox and hope people don't mind (most don't mind).

I read a good book that details the types of scenarios to avoid, and how to do that. The author is Mendiburu and a link to it is below.

http://www.amazon.com/gp/product/024...ef=oss_product

From what he says and in my limited experience, we actually want to avoid anything close to the extremes. Even parallel convergence is too much on the smaller screens. It would be OK on a screen as big as 20 ft. wide, mainly because we all usually sit pretty far back from it. But sitting 2 ft. from a screen 12" wide, it would be a real strain to see images that are spread 2 1/2" apart. It would feel a lot more like we are having to pull our eyes outward. Mendiburu gives a formula to calculate the maximum positive parallax that will be comfortable for most people, depending on the size of the screen you expect to show it on.

For sure there are things video makers can do to make their productions OK vs. not so good.

As a matter of fact, I tried to watch Clash of the Titans last night, and now I understand better what some people have been complaining about.

Yes,

in both cases the DOF is sufficient.
If you display AVATAR on a screen that is 2 feet away you will find out that the infinity or background is 3 inches deep into the screen.

Mathew Orman

I also read that half of 200% of the population think that Spoodily's post was funny and that your reply was "Total Crap"

I don't want to continue derailing a thread, so im continuing it here.


I haven't watched a 3D film at home yet, just youtube stuff. But as far you you could know, unless you've been reading some recent surveys I haven't heard about, it could very well be that "stealthily" way in which you claim they change convergence that causes headaches, causing your brain to work harder to figure out whats going on. The only way i could see doing it "stealthily" is to use blur and actually hide objects from the brain. Otherwise, it seems to me, that the brain would still be in its normal "resolve 3D" mode. Tridef 3d game software has a weird functionality where it defaults to a mode where it automatically adjusts convergence and/or depth to, i think, bring about more visible depth in a given scene; this mode also gives me short term, 1 to 2 or 3 seconds of discomfort, thus furthering my guess that headaches can be caused by all the adjustments.


Could be, but this is all really your opinion [stated as fact], its not proof. Again, point me to the surveys and studies.

Games are different than content shot by an experienced stereographer. In a game the algorithms to calculate what they think you want to focus on are not nearly as accurate as what a human being can do in postproduction convergence work for a recording. But you need to understand what the convergence/stereo window adjustments are even for: to bring the subject of a scene to a point that the viewer can focus on without too much muscle movement into the screen, and without too much movement from the previous camera angle. Having a consistency to where the primary subject will appear in Z space from shot to shot, will reduce as much as possible the longterm fatigue people get.


Based on my own experience with console/PC gaming, shooting and postproducing tons of 3D video and photos, and performing adjustments, there is a direct relation between discomfort and the screen parallax of the infinity point in the content. I can piece together two images 4 inches apart pretty easily if I'm sitting back far enough so my eyes aren't diverging at quite an extreme angle, but it takes less than 2.5 inches to get me feeling discomfort after a half hour. Also, my sentiments are echoed by general gaming forum posters, here or elsewhere, who give their impressions on what 3D strengths are tolerable for them.

I understand the concept of bringing the subject matter to screen depth. What you may not understand is that filming a bowl of fruit on a table from specific distance, then filming the people sitting at the table or a child playing in the backyard from the same distance changes the 3D depth of every single object in the entire scene if the bowl of fruit and the child in the backyard are kept to screen depth. My contention is that constant shifting of world objects might very well be the primary cause of discomfort, based on my 600 hours of off and on experience. I don't discount the possibility of it being only one of many factors, but i thinks its a factor, and perhaps an underrated one. Also, i don't feel nothing when i use 3D, i just don't feel pain or discomfort. I do still feel sensations, like a small bit of pressure, like someone placed their fingers on my head, so in fact i can sort of follow whats going on, i don't believe im am "deaf" to the effects of pain.


Im guessing you've never played a game in 3D, as there is not normally a decision made about what to focus on, the depth and convergence do not change. Everything is at a proper real world depth after final adjustments are made and remains so for the duration of the game. Perhaps you were just refering to the Tridef mode i mentioned, which sucks and is rarely even close to correct. Nvidia themselves have no auto-focus mode, and for good reason. If you've never played a game in 3D, you can see this for yourself on your 3DTV i think. I don't think it has too much depth for your screen. I've been doing nothing but discussing 3D for the last year and i have not seen anything resembling a large amount of people mention any kind of discomfort in regards to video games. I hear a lot of people fantastically excited after figuring out how to increase depth though. Film on the other hand...

2 1/2 inches apart is about the maximum for a movie theater screen to comfortably represent objects at an infinite distance. Any divergence of the eyes is uncomfortable, so the two 3d images better not ever be further apart than our eyes are set in our heads. When we view on a smaller screen, we surely adjust our perception to the size of the objects - we don't need a government study to tell us that we more or less forget how big the screen is with a good show. So directors make 3d movies for the big screen, and they adjust the convergence or screen plane continuously for effect and in order to keep the viewers' attention on the important elements, much as they manipulate focus and color. They do this stealthily, without warning or announcing, relying on the viewers' eyes and brains to follow.

3d video games are different. Games tend to be simpler than movies regarding how much variation there is in the size of things. Generally we have a first person view and the size of our character's body stays pretty constant. That allows us to set one convergence plane that works for the entire game.

Every game and movie works within a budget of how much convergence or parallax will be comfortable and for how long. Provided they stay within that range - not too close to our nose and never making us pull our eyes out beyond parallel - the 3d fans stay happy.

Agree, which is the average length between the eyes. They also have to account for children, maybe, i wouldn't think they would have much of a problem with a little divergence sitting so far back from the screen since i don't have a problem with a lot of divergence.


This is not my experience and i actually prefer objects in the infinity to be about .5cm wider than my eyes are wide. Viewed at just under 1 meter, thats some pretty hefty divergence. No pain btw. I do this because it makes epic looking structures and scene in games very slightly bigger and even more magnanimous.



Were going off topic i think, but I disagree, i don't see much depth to films. In a game, when i stand at the top of a cliff and look down at a body of water, i get a feeling of "wow, thats a long way away and far down". I've never got that feeling from a movie and its because in my experience, there is only about an 3/4 inch of separation at the most on a 55" TV. Thats somewhat made up for by sitting back a ways, but still not ideal imo.


I not sure what your getting at here, Cakefoo already made this point. When you take that "made for the theater" 3d film, then shrink it down to a TV set, you've got about 3/4 of max separation and your eyes don't stare near straight on for things in the distance and large things don't look as large as they should and decrease the depth over all.

Toying aimlessly with videogames and Youtube content is nowhere near the same as examining the effects of viewing professionally controlled convergence in film. Youtube content from amateurs almost always has flaws, and your videogame experience does not qualify you to talk about dynamically changing convergence in films that are shot with different focal lengths from shot to shot versus games, which have a fixed camera.


First off, changing depth and convergence were not what I was talking about. I was talking about excessive parallax in the statement you quoted. But even so, the statement you just made is incorrect, two-fold, in that I do play games in 3D, I have experience with IZ3D and PS3 games. And yes they do have dynamic convergence and interaxials, at least some of them do. The PC drivers aren't very intelligent from what I've experienced on IZ3D and heard and read about Tridef, but on the console side there are two games that do a pretty good job, both Sony exclusives, Killzone 3 and Uncharted 3.

This topic of convergence in gaming originated because you said you messed with convergence on your TV one day and felt uncomfortable. When you said it I thought you were referring to PC gaming drivers, but you apparently mean the TV menu itself. My point though is that you changed the bias of the TV and therefore the content did not display as was originally intended, which is far more likely why you got the feelings you did, and not because you were pulling convergence period as if to say that this was damning evidence against convergence. Changing convergence as a user who knows nothing about it and doing so on the fly with content that was not made with your convergence tweaks considered, is not an anecdotal experience that qualifies you to discount the redeeming qualities of convergence in the postproduction of a professional 3D film.

This thread gave ME a headache.

Sorry.............

Ed

Your eyes are wider apart than a child's, and you have 600 hours of experience with maximum screen parallax gaming. Your eyes are well conditioned for it.


Divergence can actually be measured in terms of degrees out from parallel, not necessarily screen parallax distance, which is partially why it gets easier on the eyes as you sit back further.




You are missing what Trick said; that some of us our eyes adjust to things and instead of looking at it like a 1:1 window that has to match the scale of the real world. The solution for your complaint is to push your convergence settings on your TV a little into the positive parallax to account for the content looking too small because it's converging closer than 1:1. You can't change the XY size of the content on your TV but you can increase the illusion that it's further away. It's better than paying more for a larger TV, and convergence will get the job done of creating a better sense of scale, as long as you make sure to keep the infinity points down to tolerable values, but that shouldn't be a problem for you.

Convergence can sound like a bad idea if you are sensitive to the relative scale to the other objects in other shots, but the effect looks better as you increase your TV size or your convergence window settings. You have limited experience in adjusting that and I think you should try putting it at a moderately positive value and leave it there for the duration of a movie that you would normally be uncomfortable watching or think had a poor sense of scale.

@TrickMcKahaOf course games and movies are differently..."recorded", did that really need to be said?


No they don't, they are adjusted by the user to account for their individual viewing conditions, ie, interocular distance, viewing distance, screen size and game FoV.




Yes, its been said, but this isn't what im arguing against. Im saying i don't think increased depth causes the problems, but that its the constant changing of convergence and depth that forces every object into a differently perceived physical position on your 3rd axis with each new shot might be the more significant contributor of discomfort. I think if the world has a constant depth and convergence, like you have in real life, leaving accommodation the only discrepancy, that would contribute to a major DECREASE in pain, and an INCREASE in depth.


My experience says your completely wrong about that. For example, there is no pain in this video, and the sword touches my nose sitting 7 ft away from my 46" TV.

You're a PC user-- there is no real universal standard there, it's a crapshoot how well a game will work with the drivers and not all games have official support. On PS3 it's much different, all the games that support 3D do so consciously, with excessive parallax in mind.



What? They're on similar if not the same positions as each other. That's the point, to reduced the need for the user to have to continually refocus after thousands of new cuts, and instead bring the content to their eye instead of the other way around. It's flexible though, it works within certain common sense boundaries, like a ship in the distance and then cut to a person's face will still have a dramatic shift in convergence for you to be active in focusing on, but in less extreme transitions that there are thousands of in each movie, they will try to keep the point of focus somewhere that makes relative enough sense without stressing the average person's eyes.


Why stop at interaxial and convergence? How about field of view too? How about no, that wouldn't work. Movies aren't solely about putting you into the first person experience like videogames are.


If Hollywood catered to you they'd drive away millions. Most people can't withstand longterm exposure to extreme positive and negative parallaxes. You're blessed with greater tolerance but cursed with ignorance.

Sure it does, since I watch 3D movies and thats the only thing that matters in this case, my brain, my eyes, and the movie. Were talking about what causes headaches, Im giving an opinion, which i state as an opinion, unlike youself who states his opinions as plain as day fact.


IZ3D never did that when i used it. If Killzone 3 and Uncharted 3 change convergence while playing the game that is too bad, because that is a very unideal way to experience 3D. Why would you want world objects to change size AND position as you play?


Games ARE configured with convergence adjustments in mind. Just today, this thread popped up, so here you go, its old news to me...
http://forums.nvidia.com/index.php?showtopic=223284

This doesn't disprove my theory that the majority of user pain may be caused more so by the changing convergence rather than


Really? I didn't know that, thanks. If i had a quarter for how many times i've had to roll back my chair from my display after I loaded up a 3D screenshot from someone elses differently sized display, i'd be a millionaire.


Okay and? My point was that that might cuase the majority of discomfort.


I know what setting your referring to and it pushes everything back or forward. That is irrelevant to what were talking about here if were talking about having bubbles in the foreground and wanting to keep them there.

You have ZERO experience authoring content. All your experience comes from playing fixed perspective content. I shoot my own 3D so I know quite a bit more about the variety of shots and convergence tweaks, and how to finesse the 3D so that it feels large yet doesn't induce a headache and doesn't have dramatic focal shifts from shot to shot.


That's because it's OPTIONAL.


It's only done in certain cases where there are extreme foreground elements to avoid stereo window violations and such. It's not intrusive. I doubt you'd even notice it was happening because it's so fast and only happens rarely, like if you try to back the third person camera into a corner between the solid object and Drake.


Old news to me too, as I have IZ3D. They give you a wide range of freedom but that doesn't mean it was intended to look that way or that it will not give the viewer headaches.

Some of my comments are based on your anecdote about getting eyestrain the first day you got your TV and were messing with depth and convergence. Ever since then I've been trying to just tell you that your convergence adjustments were probably just poorly chosen, and that you shouldn't conclude that Hollywood's convergence adjustments are a bad thing for the eyes just because your own adjustments made your eyes hurt. Hollywood is far more experienced than you are in producing recorded 3D images of varying interaxials, convergence points and lens lengths, whereas you are just experience in playing fixed perspective PC games that have a realistic 1:1 viewpoint, so you don't understand the intricacies of 3D postproduction with a variety of shootings styles other than just wide angle first person view.

Wrong, Nvidia 3D Vision, Tridef and IZ3D work without developer support via the video cards natural access to scene geometry, lighting, world camera, etc information and creates its own 3D depth which the user sets to his unique viewing environment.



Again, your making assumptions about the causes of 3D discomfort and stating them as plain as day fact. Most educated people don't do that (especially every other sentence) if you didn't know(touche' for you ignorance comment).


Links to studies are required to make that last sentence intelligently.



That really wasn't called for and its pretty much a personal attack. Were having a conversation about a little known topic of which i know know quite a bit about and have many, many, many times more time viewing the results of than the average person, and you call me ignorant? That classy.

I wasn't trying to with that statement.

I will here though: if Hollywood shot with a fixed convergence and interaxial it would disorient people from shot to shot if they went from close to far objects hundreds/thousands of times per 90 minutes. Adjusting the convergence from shot to shot to set the focus point of the main subject relatively in the same place as the subject of all other shots, will minimize the amount of work your eyes will have to do. That is the advantage of changing convergence from shot to shot. If you disagree and want to convince me otherwise, you need to provide a better anecdote than "I messed around with convergence and depth settings the first day I got my TV." You don't magically become an expert convergence puller on the first day you get a 3DTV.


Why are you upset about this?


But you backed this up by saying you experienced negative effects the FIRST day you got your 3DTV and tweaked settings that you didn't understand the physical consequences of. That's not giving the convergence technique a fair shake at all, as it doesn't compare to what expert convergence pullers do on films.

Maybe if you actually watched movies on your TV you could have a valid opinion, but you don't. You watch Youtube content and play games. Youtube content is the worst.


The bubbles conversation was yesterday. This is not what I'm referring to today. My post you just quoted was in direct response to you complaint that the screen parallax on movies at their infinity point was a max of about 3/4 inches. I said that pushing it back via the convergence setting would improve the depth you find lacking in films on your 55 incher without needing a bigger TV. Reduces popout? Sure. But you can't expect content to look optimal on a small TV when it was intended for comfortable viewing on 40 foot screens. SOME sacrifices have to be made.

And you don't know where those bubbles were actually supposed to be. All we know definitely is the size of people, and they were not on the right plane, they needed to be pushed back.

Who cares how its made when its the results that count? That C tweaks are necessary to prevent headache is an OPINION. Every C tweak is represent a drastic change to the physicality of the known environment the brain saw in the last shot. This changes over and over and over. I think this has an under-rated effect on discomfort and is worth investigating. Movies do not look at all like windows to the world and they could.


Are you serious? The original intent of 3D is to make 2D mimic reality, that means full separation at infinity matching interocular distance.


By that logic, i also shouldn't conclude that Hollywood usage of proper realistic separation values and static convergence should cause me eye strain, which I logically don't.


I understand 3D movies suck half the time if thats what you mean. I say that as someone who loves 3D...

The support pages illustrate a different story, one of varying results of sub-par to excellent quality. Also, some PC games have official 3D support, which means that they have the 3D adjustments integrated right inside the game menu, whereas other games just rely on the third party drivers and have bugs.



It's taught by experts and it solves eyestrain for me. Put two and two together.


Does the word of experienced stereographers count? Or how about the hundreds of impressions that can be read from gamers on internet forums who report eyestrain with stronger 3D in games that I know for a fact can't be exceeding the spacing of their eyes?


I'm not calling you ignorant as a person, just that you unfortunately have no way of comprehending the discomfort people experience with content that you demand of your PC games. You keep demanding a maximum screen parallax on film content, which by the way can't be undone for other people to be able to better handle. It's a serious issue that you are treating selfishly and without any consideration for the other people, as you simply can't feel their pain and know what it's like.

That is a fantasy at best because many people experience discomfort at the sight of technically realistic 3D.


If we're talking about screen parallaxes at the infinity point being 2.5 inches apart on a 47" screen, then that's going to be way too much for the average person to handle, on pretty much any TV, but especially TV's 47 inches and above.

Link to proof? Your saying it doesn't make it true, sorry to break the news... I was just remarking to someone the other day that in a year of using the Nvidia 3D Vision forums everyday, i've not heard one comment about eye strain. That doesn't mean there aren't any, but you'd think I would have heard at least one muttering side comment while being on there every day since PC gamers focus on their screens from 2ft away while frequently viewing into infinity.


My theory involves accommodation not being as big a factor as previously thought and it being variance it object position and world space changing in each shot being the issue. I've seen nothing to prove that wrong myself.


600 hours isn't a magical figure i pulled out of my arse, its going by Steam's figures, which it records. Thats a lot of time configuring settings, viewing pictures, seeing what works, what doesn't.


What does a convergence puller know about the brain?


I watch movies in theaters and film trailers from youtube and guess what, Avatar ain't S compared to a game. If they filmed Avatar, Alien/s or LOTRs with full on 3D, you'd need to repair your jaw.


That is the reality today, without a doubt, but surely with a series mirrors, multiple versions of the film could be recorded and edited in bulk to produce 2 or 3 unique versions for the theater and for different sized home displays, thus future proofing the films.

Prove it.