FOV Calculator

Discussion in 'General Discussion' started by taufikp, Mar 29, 2012.

  1. jubuttib

    jubuttib Registered

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    16.4 actually.
     
  2. DrR1pper

    DrR1pper Registered

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    How did you get that?

    Here's what i did to get 20.

    SQRT ((27^2)*9/25) = 16.2" (screen height).

    Assume eye-level matches the screen horizontal centre line.

    tan^-1 ((16.2/2)/47) = 9.778 degrees ≈ 9.8 degrees

    Vertical FOV = 9.8*2 = 19.6 **≈ 20 degrees
     
  3. jubuttib

    jubuttib Registered

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    A 27" 16:9 monitor is ~13.24" tall and 23.53" wide.

    EDIT: For easy reference regarding monitor sizes, this is a great page: http://dharmadevil.com/widescreen/ It has vertical and diagonal sizes for 16:9 (16-80") and 4:3 (13-65") monitors, inch by inch.

    EDIT2: If you're using the calculator over at http://ostermiller.org/calc/triangle.html, you can set e.g. the bottom right corner to 90 degrees, the right side to 47 (inches) and the bottom side to half the height of your monitor (6.62 in this case), the double the result in the top corner. Though I get a 16.04 doing it like that, I must check my previous calculations...

    EDIT3: Must have been a typo, because repeating my original process I got 16.04, I must have just mistyped it as 16.4 the first time.

    EDIT4: Your calculations seem to be for a 4:3 monitor.
     
    Last edited by a moderator: Jun 21, 2012
  4. Richard Busch

    Richard Busch Member

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    I don't understand this. Is this supposed to give us a more realistic FOV? What I am interested in, is a realistic seat position in the sim. When I'm sitting at my desk or driving rig, I want to look at my monitor and have it look as if I'm actually sitting in the proper place within the car I'm driving.
    I've tried these calculators. When I am at my desk with my wheel, I look at my 22" monitor from about 36" away. I've taken measurements from top of monitor to my eyes, bottom to eyes, side to eyes, etc. Side to eyes yields a FOV of 19 degrees. This puts my monitor eyes at the very front of my Brabham and my F3 car. This is not very realistic to me. I can't see the cockpit or the gauges, or mirrors.
    I've actually multiplied the 19 degree FOV by 3 and gotten 57, which, to me, looks more like I"m actually in the cockpit of the car.

    So, my question might be, what are you guys trying to do with the FOV? Are you trying to get the FOV to be a realistic depiction of sitting in the car, or what?
     
  5. ZeosPantera

    ZeosPantera Registered

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    That whole Square root system has always confused me. Just working out the angle with a triangle seems easier.

    The sites I currently use for my calculations are http://www.displaywars.com to get monitor screen dimensions and http://www.pagetutor.com/trigcalc/trig.html in which I figure out half the angle with half the screen height and the resulting X doubled equals your vertical FOV. Calculating horizontal is then just a matter of plugging in the vertical FOV divided by the monitors aspect ratio, and multiplying by the horizontal ratio.. IE 16:9 is (VFOV/9)*16=HFOV.
     
  6. DrR1pper

    DrR1pper Registered

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    Yeah i really messed up my calculation by not thinking properly. Should have written it down on paper before typing it. :(

    The mistake was in using 25 here: "SQRT ((27^2)*9/25)". I made the schoolboy error by thinking saying (diagonal ratio) = 16 + 9. When it should have been (diagonal ratio)^2 = 16^2 + 9^2 which would give 18.36.

    Therefore:

    Vertical height = 27*(9/18.36) = 13.2"

    Sorry about that and also to Tiger for giving him the wrong information. Please use jubuttib's correction of 16.4 degrees vertical FOV.
     
    Last edited by a moderator: Jun 21, 2012
  7. ZeosPantera

    ZeosPantera Registered

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    Your Desk is the cockpit of your car. Your wheel is there, Shifter, Pedals.. http://i.imgur.com/50Phx.jpg The area your monitors take up in your vision is what they would take up in you virtual "CAR" which is usually just the windshield. pillar and the top of your dash. Imagine when you are in a real car your monitor's frame exactly in front of you as if you were at your desk. What would be seen in that frame is what you should see.

    [​IMG]
    [​IMG]
    [​IMG]

    If you get your screen low enough you can even get the gauges in the right place.

    [​IMG]

    You want to make sure your Horizon line is correct for where your monitors are positioned and then probably leave the seat at 0,0 but who knows where the mod maker placed 0,0. Adjusting the seat might not work if your monitors are not in the right place. An F1 driver sits well below the wheel where a bigger car your head may be near the ceiling of the car.
     
  8. jubuttib

    jubuttib Registered

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    It doesn't actually move the "monitor eyes" anywhere. Think of it like this: Take a piece of cardboard and cut a hole the size of a 22" monitor into it. Now place it 36" in front of you, and then block out everything apart from that hole, so the only see out of the hole. That's essentially what these FOV settings emulate.

    The reasons are various. Most importantly with realistic FOV settings everything on the screen is to scale with the real world. For most people it's easier to feel at home in the game when what you see is to scale. If you raise the FOV above it you're squashing more stuff to fit the same area, meaning you're making everything smaller. This makes bends look straighter (a huge point), elevations seem smaller and makes it harder to position the car as accurately as possible on the track. Naturally it only works with either big monitors, using multiple monitors, or bringing the monitor really close. For practicality reasons it's often better to use a larger than realistic FOV. Your eyes have a huge field of view so you can see a big part of the car enveloping you at any given time, but representing that on a small monitor relatively far away squashes everything down, making the useful part of the view (windows) very small and unnatural.

    Also remember that rFactor uses vertical FOV (same setting works both a single monitor and a triplehead setup using the same size monitor, hooray!), so a FOV of 57 with the top and bottom 36" inches away from you would require either a 70" 16:9 monitor or a 57" 4:3 monitor to show everything to scale, and you'd have to set it so that a large part of the monitor was below table level (the level your steering wheel sits on) to show everything in it's right place.

    We're not saying that these are absolutes and must be used, but if you can use them comfortably (my 23" monitor sitting at just over 24" away give s me a comfortable 26 FOV, which allows me to see the dials. Adjusting my seat position further back gives even more of the dash without altering the scale, and adjusting both the seat position up/down and the monitor likewise, I can get the tachometer etc. to show behind my wheel, like they're supposed to) they can give you a better sense of the track and even make you faster. Using high FOV I'd been struggling with a particular car and track combo for almost two hours, not managing a decent hot lap, hardly managing a clean one, going from bad to worse. Setting the FOV way down to realistic levels made it easier for me to position the car accurately and see how tight the corners really were (I'd been constantly overrunning them because they looked much straighter than they were in reality), and within a few laps I was running consistent clean laps and took several seconds off my time. It really can help some people immensely, I know it did it for me.
     
  9. jubuttib

    jubuttib Registered

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    I made a typo there myself, it's actually 16.04. =)
     
  10. jubuttib

    jubuttib Registered

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    Not sure if the F1 perspective is as low as we're used to thinking.



    He says in the description that he had to drive with only one eye open because the camera was blocking the other one, so it's fairly safe to assume that the camera wasn't mounted significantly higher than the real eye level.
     
  11. evphelps

    evphelps Registered

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    EPIC FAIL!!!
    That camera is set to wide angle and does not represent a realistic perspective at all.
    It does however illustrate the distortion present in all uncorrected wide angle lenses,just watch the bridge bow as we pass under...
     
  12. CdnRacer

    CdnRacer Banned

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  13. ZeosPantera

    ZeosPantera Registered

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    19-20 seconds in it looks like the camera is well above his eyes unless his neck is a foot high since when he looks down his eyes are past his feet.

    Also a 1:07 he wipes the visor with his hand.. Well below the camera lens.
     
  14. DrR1pper

    DrR1pper Registered

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    Your error was a typo however my error was plain stupidity, lol. Though appreciated. :p
     
    Last edited by a moderator: Jun 22, 2012
  15. blakboks

    blakboks Registered

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    Not necessarily...just like with FOV in the game, it all depends on viewing distance and size of screen, and the surface you're re-projecting back onto ;D
     
  16. Spinelli

    Spinelli Banned

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    Its not like that at all. First off its lower, second you dont get this high up and eyes pointed downward view like you do in the video and 99% of mods (no idea why theyre always like that). Your looking straight on and much lower. There is no way he would be able to see the asphalt on his right side. The top of the sides of the car look like they are 2 feet lower than you, that view is a joke.

    Ill post a link with nico rosberg explaining his seat position and how he cant see crap in front of him lol


    0:44 - 0:55 seconds

    "Its always difficult sometimes to see where you are going because your sitting so low in the car. So very often I even have to lean upwards a little bit with my head, to see the corner or something depending on where I am on the track."

    1:38 - 2:05 "Its also a very very small area, like im looking JUST above the steering wheel" "Then also there is the display right here, which is JUST below where I look to see where I am going."



    Basically the wheel is in his face, just a tad (literally a tad) lower so that the display/rpm lights are JUST under his vertical centre of view point. Also, its a straight on view point, not these heightened and downward angled views we get in every game it seems (including the real sims).





    Ive seen some VERY good cockpit views with custom cam/free look cam adjustments, im not talking about fov but the actual placement of the eyepoint and the angle its pointed at. This one is pretty damn good actually, needs to be just a touch higher so that you can see or almost see the bottom of the sidewalls rather than just the top.

    [​IMG]
     
    Last edited by a moderator: Jun 23, 2012
  17. ZeosPantera

    ZeosPantera Registered

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  18. Tiger

    Tiger Registered

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    I did change the FOV to the minimum... 19 .... it's insane!
    can't drive like this...

    so, I tried some more values, and finally got a FOV=45 and there it's really fine!
    so, I don't know what this values means, whatever the definition of FOV is...
    with the seat I got, and with the driving position I have, this angle is just perfect ;)

    thanks anyway for help ;)
     
  19. taufikp

    taufikp Registered

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    This is iRacing using low FOV (according to the video uploader's comment). Using Cinemizer OLED (a Zeiss' product) and TrackIR 5.
     
  20. argo0

    argo0 Registered

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    Using a 32" Sony with a playseat tucked under the TV stand, my correct FOV is 26 according to the calculator linked to in Zeos original, very useful FOV advice thread. I compromise with 32 FOV, giving me just enough of a view of the front tyres (open wheelers) and a bit of side mirror. Combined with Real Head Motion plug in and 100% look ahead I still retain enough 'shake' to give me a hugely immersive view that frankly is very hard to fault now.
    I used to be lost and guessing about this view stuff, often trusting devs to know what they were doing with it (no longer!) until my Sim Racing experience was transformed by ZeosPantera(FOV) and Sebastien(Head motion). Thanks guys, you've changed my sim racing immeasurably for the better.
    I should also mention that I use virtual mirror where necessary, have my glance angle in the plr set higher to give me a view of my blind spot and have altered the pitch value in plr to lift my head up a bit.
    All this combined gives me a great scale of things, proper elevations, real looking corners, my car rolling and pitching round me, restricted view in modern F1, immersive tin top view that makes me forget I'm not actually in a car. Playing RF2(well done ISI) with this lot sorted and a G27 is an awesome, jaw dropping experience.
    Thanks for the enlightenment guys. I'm having the sim racing time of my life.
     

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