FOV vs POV, we have been doing it all wrong! (game changer)

Discussion in 'General Discussion' started by green serpent, Jul 31, 2021.

  1. green serpent

    green serpent Registered

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    Hi guys, PLEASE watch the whole video and provide your feedback. This is a game changer IMO (figuratively and literally!) I'm sure that other people have thought of this before and many are already doing it without really knowing why, but I came up with it on my own as I haven't seen this information anywhere else. I feel it's important for proper simulation, and that this should be considered "best practise". It is probably already the set standard in professional simulators and I've come up with nothing new and am late to the party. Still, I feel I want to get this out there and share it with the community to see what you think!

    Please let me know if I am correct! What I interested in is if this is a) mathmatically and geometrically correct and b) if it actually makes the driving feel more realistic and is the "gold standard" of configuring your viewing position and perspective.

    Thank you!

    Edit: I now think I was wrong in saying the way the game does it by default is incorrect. Still, I am glad I made the video as it was basically just an elaborate way of asking a question, and I was able to get my question answered to my satisfaction!

     
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  2. doddynco

    doddynco Registered

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    I had the exact same thoughthowever, it's not correct. There is no 'image plane' other than your screen; there is an in-game camera position, and it remains stationary in-game regardless of the FOV setting.
    O
    When you look at your screen, you're not looking at 'the position where the camera is'. The FOV effectively determins how far back from the screen the virtual camera sits in real space (that the wierd bit to wrap your head round). A FOV set too wide and the virtual camera is effectively moving further and further forwards of your eyes (in real space). The idea is to match to position where the vitual camera sits in real space and where your eyes are positioned (in real space) by using the in-game FOV adjustment.

    That being said, I completly respect your thought process here because it's an incredibly strange thing. No need to feel silly !

    Edit: You have your verticle and horizontal FOV mixed up, which is why it looks wrong in your vid. Assuming your screen is 16:9, you need to set your FOV to about 35. (WRONG)
     
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  3. green serpent

    green serpent Registered

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    I don't think you are right, but I respect your opinion! I will think about it some more though, thanks.
     
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  4. Nieubermesch

    Nieubermesch Registered

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    You're definetly right about this mate. I've been doing it instinctively to place myself correctly on the seat of the car as much as possible. I have a 27 inch monitor and I set it to around 37° as I'm at around 60cm from the screen. I just mess around with the seat position and normally it has to be positioned forward, so as to - as you say - place myself in the real world where the seat would be in the virtual world (one can just imagine that and intuitively figure it out by messing around, no math needed).

    By the way, FOV and bigger or smaller screens will make no difference to this POV. What will change it is simply the distance one is from the screen. Since what FOV is really all about is a "window" to the virtual world, it will be smaller or bigger according to the size of the screen, but the plane that the monitor slices in between the real world and the virtual world, will remain the same, and so one must set the camera/seat accordingly to the distance to that plane.

    My mind has been too sluggish lately to help you with this, giving a clearer explanation, but you are definetly right. There is the perfect spot to aim for, but to be somewhat in the correct margin will still give a much better feeling then those who have to drive very far from the screen. In that case it will be pratically impossible to achieve satisfactory results. The farther you are the more you need to move forward the plane in relation to you, so you would probably need to be outside the car in the virtual world, wich makes no sense of course.

    FOV is a very inportant factor in this too, but in another way. The smaller the FOV the less you will feel you are inside the car and what you see in the screen will move away to fast for your eyes and less geometry of the car you will be immersed in.
     
  5. Nieubermesch

    Nieubermesch Registered

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    His FOV is correct mate. 35 would look really silly on that big ass screen, I can assure you.

    POV matters not only to give an accurate placement of yourself in relation to the real world, but also because most cars are closed off and because of this, most people will prefer to have the camera moved forward so not have too much in the way of focusing on the important stuff, the road. Too far back in the seat and you will have your side of the car blocking your view and how much of some tight corners you can see... Most people will not have huge monitors or triple screen setups to work around this.

    The FOV is a result of the size of your screen and the distance you are from it. Once you figure that out you still will end up with a problem. Imagine a car where the seat is already set up quite forward. When one needs to (normally) diminish the FOV you will end up with a plane (screen) placed probably in the bonnet or in the windscreen. If you didn't have to care about POV this wouldn't happen. Where you place yourself inside the virtual world matters and even if the FOV will remain the same, the size of the objects that are closer to the car will be larger the more you move the camera forward... This tells you everything. It tells you that you need the POV right to where your eyes are if you imagine the virtual world all around you and the objects size to be correct you need to be in the right spot in the virtual world (the camera, or plane of view).

    My mind is proned to consider very complex things while I can't process them quite well as I'd like, but I hope I made myself understood. My brain hurts right now :confused::confused:.
     
  6. green serpent

    green serpent Registered

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    So subjective preferences aside, do you think that technically speaking, that for a mathmatically correct view, that one should not only set the FOV, but then place the virtual plane of view ahead of where the game has it by default (eg, do you tend to agree with what I have said in the video?)

    To put things another way, I was just driving the Miata. Lets assume that in real life, you can reach out and touch the gauges like the speedo with your hand (never driven a Miata but I assume unless you are legally a midget you could do this).

    Bare with me... So, with a correct FOV, BUT a default images plane (image plane at point of racing drivers head), I could reach out in front of my toy steering and touch the "gauges" in the real world, but then, if I physically move forward one meter (so my physical eyes are against my screen), I would have to reach out AGAIN another vitual meter to touch the virtual gauges. There's a double up of objects in the close forground.

    I should say that unless you are sitting fairly close to a big screen, this kind of accurate FOV and forward image plane will be difficult to drive with. But with a decent sized screen (eg 75inch) sitting about a meter away, it's not only difficult, it's easier to drive and it just feels right to me. This lends me to err on the side of it being technically correct also.
     
  7. Lazza

    Lazza Registered

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    Seat position is only done 'by feel' if you compromise on FOV (ie not real), and everything is then not quite right - but adjusting the seat position may help somewhat.

    In your case a normal (1080p) 27" screen at 60cm should be about 31° vFOV. (is yours 16:9 or something else?)

    With real FOV, the camera should be where the driver's eyes would be - generally very close to 0,0 in the car. Your distance to screen can't change that itself, because changing your distance to your screen also changes your correct FOV - and that then results in the correct view.

    @green serpent it's easy to get confused with this stuff, but I think your understanding of an "image plane" is wrong, and that means the rest of your (otherwise correct) reasoning is unfortunately all a little off.

    The screen image is drawn based on all the in-game object positions relative to the in-game eye and the virtual screen - which is forward of that eye (and the intersection of a line between each object and the virtual eye, and that virtual screen, determines where that object is drawn). If the image plane were where you've drawn in, the virtual eye would need to be further back, and that would be reflected in your apparent position when rotating the view. You need the separation between the eye and plane in order to draw the image.

    So, correct FOV, correct eye position, all is correct.
     
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  8. green serpent

    green serpent Registered

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    So in this case I am seeing the simulated world through the point of view of the virtual driver, yet I'm sitting 1m away from the eyes of the virtual driver. In this scenario, there are two seperate point's of views. The point of view of the virtual driver, and the point of view of me sitting 1m behind the point of view of the virtual driver. I am saying that my point of view and the virtual point of view should be one in the same.


    But that is not the real point of view. The actual real point of view is projected (eg) 1m out from the screen.

    You have to tell the sim "this is the point of view", and you tell it that by moving the image plane. I'm using the term point of view literally.

    Perhaps I am simply all wrong about this, just trying to get my head around it!
     
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  9. Lazza

    Lazza Registered

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    What's drawn on your screen is what would appear on a virtual screen in front of the virtual driver. Both you and the virtual driver are behind that screen, in accordance with the FOV. If you have it set correctly, you are the same distance from it.

    There isn't an image plane at the virtual eye. Such a plane would produce no image, because the eye point is where all lines converge.
     
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  10. doddynco

    doddynco Registered

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    I'd a
    I'd add to this that, the reason it feels better to drive with your preferred camera position in the video is because you're making visibility better than in the real car. You can see more of the ground immediately in front of the car which gives a great sense of speed. You can also see more of the tyres which allows you to be more precise with your positioning. These two advantages will probably outweigh the benefits of a 'correct' camera, especially on a non-ideal setup. I know because this is my preferred camera when I'm using a similar setup.

    So with your chosen camera, you can see things which are impossible to see from the pov of a driver in the real car, like say, a car number on the nose cone, or perhaps more of the front wing than would otherwise be possible.
     
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  11. green serpent

    green serpent Registered

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    I believe you are correct sir.
     
  12. Nieubermesch

    Nieubermesch Registered

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    Sorry, I am actually 50 cm to the screen, my bad.

    I think you are probably right. With the correct FOV you end up with a virtual screen wich in most cases is "pushed forward" - its actually just a "zoomed" in image. After that you will end up being in the correct position. I guess this will only be a problem if the mod doesn't come with the virtual drivers eye in the correct place. I guess after the FOV is somewhat correct then doing some feedling with the seat position is still valuable because of how it helps with visibility in my opinion. But I think POV is relevant like OP says, even if he and me were thinking about it wrongly. Its important because you can mess it up, but normally it will be fine if FOV is correctly set I guess.

    Thanks.
     
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  13. Nieubermesch

    Nieubermesch Registered

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    Yeah, now that I think about it again we are (probably) definetly wrong. I guess the talk of the image plane confused me too. It's not really that way it works. It's a slice, but it will be a slice further down the perspective you are seeing, no just in front of you, so everything should be correct.
     
  14. Richard Busch

    Richard Busch Member

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    Nice video. I've been trying to get my head around the FOV and POV settings in Sim Racing for 20+ years, and I still have a hard time with it. When Studio 357 release a car, shouldn't the drivers head already be placed in the correct position in the car? The image plane is set at the drivers eyes, relative to front/back side to side? Elevation up or down depends on driver height. Each class of car would therefore have a different Driver head position relative to steering wheel, windshield, mirrors, fenders, etc. I got lost when the OP started to try to move the head forward to get it where he thought it was supposed to be. Shouldn't it be where it should be when the car is designed/modded/made and released? All we should have to do is set the FOV for where we sit with our Monitor/TV, and perhaps up/down.
    I get lost trying to find out where the drivers head should be relative to the FOV. If my rF2 FOV is 21, where are my head/eyes supposed to be in the sim car?
    Sorry if this sounds confused. I've been trying to understand for years. lol

    After watching the video, I made some changes and moved my seat view back as far back as it goes. and it seems right to me. I guess everything's just personal preference, but realistic is what we're really after.
     
  15. Nieubermesch

    Nieubermesch Registered

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    Well, by your very limited FOV value, you really aren't even seeing the car in the screen, are you? Wouldn't imagine you being able to, or at least very limited parts. In this case you going as back as possible will probably yield not much of a difference? How much more of the car do you see?

    Head up and down is important for sure too and being too low or too high up can make you feel strange "inside the car" just as much as a drastically wrong set up for horizontal POV can feel.

    I guess in the end the POV( opinion) of the OP and also my previous before thinking this better, is basically not right. POV is quite important, but it's not a matter of fixing it if the car is propperly set to around the ball park of where the head of a driver would be. Where it gets tricky is that seats in real life actually change, so its actually not unrealistic to set this up and mess around, it only becomes a problem where you start to seat too far back or too far forward in relation to your FOV.
     
  16. mantasisg

    mantasisg Registered

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    To me this looks like trying to get better depth perception slightly further, and completely loosing it in the near plane where the actual instruments are and the steering wheel is. And even with that monster screen you don't even see them, it is this much how you sacrifice view in near plane and peripheral vision too. And most people will never have to drive with monitor this size. Way more realistic option is VR, it would be both more realistic visually and in terms of practicality comparing to TV this size.

    I don't think your thinking about this image plane is correct as humans don't see as that in the first place, the most realistic screen would probably be something curved of 2m radius, going 180degs around you.

    [​IMG]

    I personally have two simple principles for FOV, that I apply and try to do best compromise of two:
    1. Seek for realistic FOV
    2. Seek for realistic peripheral vision

    The result is simple, can never have correct fov without loosing all peripherals and can't have all that would be visible peripherally, so just choose most immersive and informative view possible that does not warp an image, and just don't care about realism of vision on a flat screen, especially if it isn't size of a full wall of a room.

    Having more view peripherally I actually feel more like in drivers seat, I feel visually the way car yaw angle changes with more sensitivity, also it is more fun as sense of speed is better. I see next to no benefits to chase for realistic fov angle, the less the smaller the monitors goes.

    In VR it looks like you truly see real wheels in open wheelers, the inclinations of hills looks real and a lot steeper than on screens. On screen you might get your front wheels to look about right size with TV this big, but image is all wrong anyway.
     
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  17. Lazza

    Lazza Registered

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    You can get everything looking correct on a screen, and with triples you can get excellent horizontal coverage. Even my 27s give me 160+ degrees horizontal, but yes, vertical is lacking.

    Everything I can see is correct though. Being a flat screen doesn't compromise the perspective.
     
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  18. mantasisg

    mantasisg Registered

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    @Lazza Obviously with triples, I doubt it is excellent if monitors are not curved, but with three screens you can get three planes on different angles, so it is close enough for horizontal width of vision I suppose.

    There is one thing that definitely isn't correct with flat screens, even triples. That is depth perception. It is the only reason I'd buy VR someday. I think what OP has tried with this topic was to get more realistically scaled view up front at around front axle, but it is just too confusing to me. With VR it is great having everything appearing at correct scale and in correct distance, near or far plane - no compromising, just not possible with screen.
     
  19. green serpent

    green serpent Registered

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    Sitting close to a very large screen with realistic FOV, If you're looking at the screen from a slightly different perspective or from further away, it looks distorted as hell. Someone once commented that I drive with quake FOV so it's fake. But from the correct point of view (as LAZZA said where all lines converge), even on a flat screen things look fairly accurate and not too distorted.

    Having such a large screen was simply a result of wanting two things (which is what you wanted), real FOV, and peripheral vision. Wide FOV and real FOV are not mutually exclusive as some people think.

    Also on such a big screen with realistic fov, hills and the camber of corners look pretty epic.

    However, I am uming and ahing about switching to VR (Pimax). Virstly, for maximum realism, idk if I could deal with seeing virtual hands on a virtual wheel indead of my own hands on a "real" wheel. Secondly, I like to have friends over and we watch on as we both do hot laps, it's almost like we're in the virtual car together (perhaps even with VR I could set up a seperate monitor?)

    In my next house where I can have a bit of a man cave, I am likely going to set up with biggest wrap around monitor I can afford (maybe a projector?). I really would like more peripheral vision for that sense of speed, but also for when people come to try the sim I want them to be blown away by such a viseral and immersive experience.

    My first experience with VR was not great (letter box vision) However, Neils has beeing making me think just go to VR with his videos, particularly the PIMAX with the wide FOV it has.

    Has anyway had the opportunity to try both an absurdly large curved monitor/projector, vs VR? I'm unfortunately the kind of person where if one thing is a little bit not to my liking I just can't get on with it. I can't tell you the amount of times where everyone else has been totally satisfied about something and I'm the only one who's crumpy as hell about it because there is one tiny thing off. I feel like with a real physically monitior and seating position I can tweak things until it feels right.
     
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  20. Lazza

    Lazza Registered

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    Let's be clear about something - you as well @green serpent - the perspective drawn on a flat screen is completely correct.

    Yes, it relies on your eyes being in exactly the right position, and yes, it's 2D so no actual depth, but there is no distortion from being a flat screen. In fact if you have a curved screen and don't have any third party correction then you do have distortion.

    The game projects onto a flat plane. Flat is correct (with correct FOV, and eyes perpendicular to the centre of the screen(s)).
     
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