3D - 2 simultaneous 60 Hz images, or 2 images at 120 Hz alternating?

Guys I've been playing sims for the past few years at over 90 fps (try to keep my minimums above 90, and capped at 120). Even when I couldn't see the extra frames in my previous 60 Hz monitor I still felt more control, more precision, etc. (many others have noted this as well.

I really want to get into 3D for the increased depth perception, speed judgment, etc. The thing stopping me was the 60 fps. Then I remembered that if jt's 60 fps per eye that the game engine in the background may still be pumping out and working at 120 fps, if this is the case then I am so happy and will most likely buy a 3d kit soon.

What I am wondering is.....

3d games basically project the image from 2 very slightly djfferent viewpoints (like our real-life eyes do), so, does the game send these 2 images to our shutter glasses at 60 fps each and both at the same time and therefore the game itself is still running at 60 fps however it needs to output 2 seperate images at the same time? Or, is the game engine running at 120 fps but then it alternates between sending one of those frames to one eye and one to the other.


Method 1 - 2 different viewpoint mages updating simultaneously at 60 fps and therefore game engine only runs @ 60 fps (pumping out 2 different images for each of those 60 fps)

OR

Method 2 - 2 different viewpoint images updating alternatively at 120 fps and therefore game engine runs @ 120 fps, but the 2 images each take turns alternatively outputting each ones image after the other and therefore each eye only sees 60 hz/60 fps, BUT the game engine itself is still processing/running at a true 120 fps.

 

Method 1 is used at movie theaters. The glasses are passive, and are just polarized in different directions. That's why if you tilt your head sideways everything gets really messed up.

Method 2 is the method used with LCDs like your monitor. These use active 3d glasses with what basically are shutters that alternate. So I figure the setup you're interested in is of this type.

EDIT: Looks like both methods are available now for computer use.... Though I think method 2 is much more widely spread at the home.

So, to elaborate further....

Method 1:
Light can be described as waves. There is a direction that the waves are oriented in. The way polarized sun glasses work for instance, is that only the light that is oriented in the same direction as the slits get through. Let's say your left lens is oriented horizontally and your right lens is oriented vertically. If the screen displays light polarized horizontally for the left eye and light polarized vertically for the right, then the image will appear in 3D. These timings can be coincided, especially if using a pair of projectors.

Method 2:
The glasses have what are basically shutters. These flicker at 60Hz, but with opposite phases. So when the left eye one is open, the right eye one is closed. The computer switches the perspective between the two 120 times a second. Hence, it appears to be a 3D image.

 

Ok so therefore if I use nvidia 3d vision then although the Image I'm seeing is 60 fps, the game engine itself is still running at 120 fps, correct?

 

Yes. That is correct.

 

Im reading conflicting reports on vsync. Some people say its forced on in 3d no matter what, others say its not...

 

older nvidia cards ( pre 600 series ) force vsync , the fps will not run higher than 60fps per eye

600 series & onwards the user has the option, I run with sync off & like to cap at 121fps (per eye )
(although I can't really achieve this in rf2)

the fps reading is half the amount of frames being produced
each frame is a set if 2, so if the fps says 75 it's 75 x2 (1 frame per eye)

 

I'd love to try rf2 with 3d (without spending the money haha), you say about depth perception, and I note the new ferrari sim uses 3d, but for me every time I see something in 3d I think of those "magic eye" pictures. If you ever looked at one of those and managed to see the picture you may understand what I mean. To me it looks like a load of 2d cardboard cutouts arranged at different depths, but all in focus. I always viewed it as a novelty rather than an enhancement, always willing to try something new though. Does it work properly with multiview? Don't the side monitors look wrong until you look directly at them?

Spinelli you could probably check the vsync thing by running rf2 at a setting that gives you more than 120fps and make sure you don't have any fps cap set. If you see framerates higher than 120 vsync isn't forced. If you only see 60 90 and 120 fps it is forced.

 

3d vision (providing you have a PC that can run it seamlessly .....& decent software that's fairly optimised etc)
is a total must not a novelty ( real world 3d vision is not a novelty ) it's impossible for me to go back to 2d it looks like some strange flat cartoon.

3d is the natural way we see things, for a PC high fps is important for natural looking 3d etc for racing sims it really adds a serious dimension

 

I have Nvidia 3D Vision and it defninitely needs VSync. Your 120Hz monitors alternates between an image (a complete one!) for your left eye, then your right one, left one again, right one again etc. Your shutter glasses are synced to that and cover the eye which is not supposed to see the image for the other eye. Imagine this would run without VSync.

Just imagine the shutter glasses cover your right eye, you are supposed to see the image for your left one. Your graphics card was too slow though, sending an image to the monitor with only half the image rendered, the bottom still being the one from the previous frame for your right eye... Same happens in the next frame for your right eye, where the bottom is still that from the previous frame for your left eye. You'd basically see everything doubled (like if you wouldn't wear the shutter glasses at all, only the frequency of the "seeing everything doubled" would be cut by half).

I guess your head will simply explode after looking at that mess for more than 30 seconds.

 

older nvidia cards ( pre 600 series ) force vsync , the fps will not run higher than 60fps per eye

600 series & onwards the user has the option, I run with sync always off
(vsync is not good for simulators )

the fps reading is half the amount of frames being produced
each frame is a set if 2, so if the fps says 75 it's 75 x2 (1 frame per eye)

*****vsync & monitor refresh rates are two different things

 

Noone said they are the same.

 

Ok so let me get this straight. The 3D works just fine without VSync? (I CANNOT HANDLE THE INPUT LAG ASSOCIATED WITH VSYNC). Adrian, do you still lock the fps to 120 in order to have an as much VSync look as you can? Or is it just no different than a 2D monitor where the image itself looks the same regardless of fps (with the exception of possible tearing and/or stutters, which is understandable)?

If I can use 3D WITHOUT VSync for my sims (I usually keep VSync enabled for all other games), while also having my sims run at at least 120 fps (regardless if I can only see 60), then I'll definitely go the 3D route. The depth perception, closing speeds to other cars, hill decline/inclines, the way you look "into" and "around" corners, etc. is supposed to offer a slight advantage especially when it comes to presenting the sim to newer players that aren't too experienced as the 3d, in combination with a nice low/realistic vertical FOV + triple monitor combo, is supposed to make things seem a lot more natural and instinctive for newer players. Plus, the immersion and overall fun factor is supposed to be incredible. Apparently the 3D from video games especially the "true" NVidia 3d vision developed games, are supposed to be on another level than the 3D movies you see in theatres.

Apparently the games that use the "fake" 3D have this sort of "2D cardboard cutouts arranged at different depths" look. Apparently Crysis 2 (not sure about 3) is an example of this. However, the games that have "true" 3D apparently do not have this "look" to them, apparently they are amazingly natural and realistic.

There are websites/forums that list which games use the "true" style and which use the sort of "fake" style. Having said that, many people even find the "fake" ones to be extremely immersive and enjoyable, but yes, the observant/analytical ones may notice the difference.

Does anyone know if RFactor 1 and 2 use true 3D?

 

Once again, I can only speak for Nvidia's 3D Vision, but yes, it's exactly the way you wrote. It will "look" like 60fps because your eyes will only see an image every second frame, alternately. This is why it's important to have a 120Hz display (which you have) since the framerate of what you see is, of course, cut in half. Internally, the game will still run at 120fps. And once again, the graphics card HAS TO churn out full frames because you can't let a part of the image from the previous screen stay because it way from the OTHER EYE. You would see double. But your graphics card is beefy, it will have no problems whatsoever.

Mind you, I just tried 3D Vision in rFactor 2 again just yesterday because of this thread.
I am allergic to input lag, just like you. My ingame wheel has to turn without any delay compared to the one I'm holding in my hands. I don't notice any input lag with and without 3D Vision.

If you know how to crisscross your eyes to see a 3D image (dunno how to explain that in English ) you can see what 3D Vision looks like in rFactor 2 with those 2 screenshots. Both rFactor 1 and 2 are true 3D. Notice the difference of the driver's left arm position in the first shot. It blocks the path to the gear number a lot more correctly for the left eye (right side of the screenshot):





Sorry for the image quality, but it's impossible to capture 2 frames via Fraps or rFactor 2's ingame "F12" method. You will always capture the image for the left eye I think, you'll never capture the one for the right eye. The only option to capture both is using Alt+F1 when running in 3D, but the image quality is quite low because Nvidia uses heavy JPG compression with that even at 100% quality settings.
Plus, as you can see in the second screenshot, rFactor 2 has one very big problem: tires. The higher you set the 3D effect's depth, the more hey will be drawn offset. They are only in their correct position if you turn down the 3D effect to 0, so you'll have a flat 2D image again.

 

hiya Spinelli

I always run in 3d vision

in iracing I cap at 121fps ( without cap the fps shows around 180 to 280fps )

in rf2 I leave uncapped fps shows 45 to 95fps
-the nvidia driver 334.xx seems to run very smoothly no noticeable tearing or defects most previous drivers gave sloppy visual performance at these lower fps (not tried the very latest nvidia driver as away snowboarding for a month)

I ise to have gtx580's which force sync & I use to detect some lag due to this, this is why I upgraded to the Titan,
I never ever run with vsync on, like you I'm sensitive to noticeable input lag etc

 

Again, you cannot run 3D Vision without VSync. No matter what graphics card, driver, game, anything. Using 3D Vision and shutter glasses requires VSync. It's technically impossible to run without (well, it is actually, but you'd see everything doubled, like looking at your monitor without your shutter glasses when running Stereo 3D). You can use Nvidia's control panel, the inspector, ingame settings, they all don't matter. The driver will override your VSync settings automatically as soon as you enable the Stereo 3D mode.

SOURCE (Read posts #2 and #6, the ones from Andrew)

SOURCE



Both of you have very beefy graphics cards. I don't experience input lag with my weaker GTX770, so it's only natural that a Titan/GTX780ti should work even better.

 

I'm going to take a stab at this...

Without VSync on, not all pixels are necessarily updated in the memory of the graphics card. With VSync on, it forces all pixels to have to be updated before refreshing the displayed image. Therefore, VSync fixes screen tearing.
Now, recall that active 3D technology requires a constant switching between viewpoints. So, you display the image on the left eye, then the right, then the left, etc. Let's say you try running active 3D without VSync. This would imply that there is no guarantee that all the pixels are updated before refreshing the screen. So, when you switch from the left eye to the right eye, you may still see many of the pixels that are from the left eye perspective. As such, active 3D must have VSync enabled to function correctly.

Is that correct?

 

hiya robert

i think you've been getting a tad confused between the shutter glasses synchronisation ( to monitor refresh rate 120hz ) & vsync

& your information is out of date

the shutter 3d glasses will left shutter for the even number (monitor) refresh
& the right eye shutter for the odd number monitor refresh so these are perfectly synchronised to the monitor (this is not vsync )

vsync works by if there's a call to refresh buffer on the screen (openGL or DirectX API call), the driver simply freezes the game engine until it is time for monitor to refresh itself which usually the main cause of increases "lag"

for anyone that dosnt realise that nvidia 6 series (& onwards) do not need VSYNC to run with 3d then please look at your settings ( nvidia control panel & of course keep off in sim ), if youve been running with vsync then your in for a treat.

trust me i dont have to use vsync & run in nvidia 3d vision all the time
(but of course the shutter glasses are synchronised with refresh rates but this is not vsync )

since the 6 series nvidia cards, vsync has absolutely nothing to do with 3d vision
in fact it never did in a technical sense as nvidia only forced it (prior to 6 series cards) hoping users would get a smoother visual experience until people started complaining about dreaded lag, although they may still recommend it (which surprises me) they do not force it (again 6 series cards & on)

I'm away for a months snowboarding at the moment, on my return I'm very happy to make a quick video showing my settings ( vsync off in nvidia control panel & in sim) and you can see the fps going way above 60fps or 120fps I can show fps over 300fps whilst in 3d vision ) for me vsync is a sim killer I never run it on.

p.s not trying to offend you in any way I'm simply trying to help you understand etc

 

hiya

incorrect, vsync dosnt effect 3d in the slightest

ghosting is a shadow image due to the monitor not being fast enough, eg each refresh is an constant alternating image
(alternating between the left eye view & the right eye view ....exact as in real life vision) as the switching is very fast at 120 times per second the monitors pixels can over shoot the refresh (imagine it as a light switching off but it glows down quickly after you flick the light switch).
my monitors ghost for about the first 10 minutes (monitors warming up to optimal pixel temps etc) but then any ghosting is unnoticeable, vsync on or off makes no difference to monitor ghosting in the slightest.

 

I do understand how they work, trust me.

This is correct.

The game engine is not frozen. Your monitor has a fixed refresh rate which refreshes your screen after a fixed timeframe (at 120Hz that would be 8,333...ms). VSync eliminates tearing by only sending completed frames to the monitor. In an optimal solution, your graphics card is powerful enough to churn out as many frames per second permanently as your monitor's refresh rate is, in this case 120fps. It will render each frame in 8,333ms or less and send it to the monitor every time the monitor reaches the point it will refresh the image. What happens though if your graphics card falls below 120fps is that it has not completed the entire next frame (because it took longer than 8,333ms to render it). It will not send this incomplete image to the monitor when the monitor wants to refresh, instead, it sends the previous frame again. What the user will see on screen is the same image twice. Technically, it looks like you are running with exactly 60 frames per second, because you'll see each frame for 16,667ms. This produces "lag", but a low framerate is basically the same. The lower the framerate, the higher the input lag. Simple.

VSync is on. Like I wrote in the posts above, you can set your drivers, the Nvidia Inspector, ingame settings and everything else to force VSync off, it will still be enabled when you are running 3D Vision. It can't work any other way, and I wrote in the posts above why this is the case. Your shutter glasses are always in sync with your monitor's refresh rate, correct, but what happens if you are not running VSync and the monitor shows images which are not 100% complete (tearing)? Exactly, you would see the bottom of the image from the previous frame which was rendered for your other eye.

So if you really hacked your drivers to let you play without 3D Vision, you would see something like this:



Try to crisscross, but get ready to puke.

Correct. See the screenshot above, it's exactly what you explained.

 

hiya

I've not hacked anything & also (thankfully) not used vsync since getting the Titan.

just a question as you think vsync is enabled (what ever you do in settings) then your fps is locked at 60fps or maxes at 60fps ? (whilst in 3d vision)

in 3d vision there is no noticeable tearing, but without vsync it can look "jumpy"
but recent nvidia drivers have greatly improved this so I now get a very nice smooth experience in rf2 ( iracing i cap at 121fps also around 146fps is smooth too, also capping fps isn't the same as vsync so this is preferred )

I'm also fairly sure that after the 6 series cards their were no exceptions so your 770 should run 3d vision with no vsync

p.s I don't use nvidia inspector -just standard official nvidia drivers

also I didn't just jump our of an orange yesterday lol, I have built various pc's for people & on my 6th generation of self built PC at the moment & had various AMD & nvidia cards as well as stress tested gpu's, I'm also happy for you to run vsync if you can't believe there is another option it's of no benefit to me to argue etc.

*gtx 680 launched close to mid 2012 & it is taking a while for users to realise 3d vision (on these & later cards) dosnt require vsync .....perhaps partly due to bad communication by nvidia