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iRacing FOV - how to - optimium angle and FOV for realistic view

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iRacing optimal FOV calculator.zip

 

I wanted to share this information that was posted some time ago by David on the iRacing forums. I have seen some FOV posts and I myself did not give it much thought initially,  I did find that I approached the FOV problem incorrectly, I setup my FOV based on my monitor angle. Doing this will allow you to maximize your FOV (i.e.179) but it will not correctly scale the interior of the car to the real world. To find your optimum FOV and match the real world size you need to determine the monitor angle first by using the width of your monitor.

 

here is the equation

 

monitor angle = 2 * inv(tan)(monitorWidth/2*viewingDistance)

 

You can physically measure your monitor width or better yet look it up on the monitor specs.

Viewing distance is easy to measure as you can use your sitting position to the front monitor from your eyes. There can be some margin of error here depending how you hold the measuring tape to your face and ensuring it runs level to the screen to get the accurate distance. Try to be in a relaxed position when doing this, as when you would be when in a race.

 

1.monitorWidth:

   In my case I use 27 inch monitors with a monitor width of 642mm (sorry I prefer metric to get more accurate results and it works better in the iRacing calculator). The conversion is inches * 2.54 * 10 = mm.

 

2. ViewingDistance

  My measured viewing distance is 610mm. 

 

so I get 

 

   monitor angle = 2 * inv(tan)[642/1220]

   monitor angle = 2 * inv(tan)[0.5262295081967213]

   

to calculate inverse tan, you can use windows calculator (put it into scientific mode ALT-2), enter the long number 0.5262295081967213 and then hit Inv then hit tan-1. You should get 27.754669264612328606718166212152,

 

That number times 2 will give you the monitor angle that you should use at your particular sitting distance.

In my case that is approximately 55.5 degrees. Multiply this number by 3 and you will get the maximum FOV value you should be using in game. So for me its 166. If I wanted to max out FOV at 179, and I can do this in game, the cockpit will move further away and its size will no longer represent the life sized view. In order to achieve 179, if that's what we want, we need to adjust the sitting distance or buy bigger monitors. Lets look at both scenarios now. 

 

so, starting with 179, we have to divide it by 3 to get the single angle between monitors

   179 / 3 = 59.667 which is approximately 60 degrees for our analysis

 

case 1 : viewingDistance

 

We need to solve for viewingDistance

    from,

        monitor angle = 2 * inv(tan)(monitorWidth/2*viewingDistance)

   we derive,

        viewingDistance = monitorWidth / (2*tan(monitor angle / 2)

        viewingDistance = 642 / 2*tan(60/2)

        viewingDistance = 642 / 2 * 0.57735026918962576450914878050196

        viewingDistance = 556

so to achieve a realistic size on screen with my 27 inch monitors to have a 179 FOV in game I have to sit 556mm from the screen.

 

case 2 : monitorWidth (at original viewing distance of 642mm and monitor angle at 60)

   from,

      monitor angle = 2 * inv(tan)(monitorWidth/2*viewingDistance)

   we derive,

      monitorWidth = 2 * viewingDistance * tan(monitorAngle/2)

      monitorWidth = 2 * 609.6 * tan(30)

      monitorWidth = 703.9mm

 

ok what do we do now. We need to calculate the hypotenuse. Recall ? :)  S=OH C=AH T=OA (wikipedia it)

    Since we have the width, and we know the aspect ratio of the monitor 16:9 we can calculate out the optimal monitor size for this sitting distance to achieve 179 FOV at 60 degree monitors. We need to use C=AH. For this we need the angle between the bottom length of the monitor and the side height that runs along the diagonal. This is detemined by just using the monitor ratio. If you have a 16:9 monitor, then that angle is 29.36 and if you have a 16:10 monitor that angle is 32.01. Since I have a 16:9 aspect ratio monitor I will use 29.36.

 

cos(angle) = adjacent length * hypotenuse

cos(29.36) = 703.9 * hypotenuse

hypotenuse = 703.9 / cos(29.36)

H = 807.6mm or 31.8inches. 

 

So for my sitting distance to run a 179FOV with iRacing and get a realistic size (all this assuming iRacing built their calculator in game for this purpose) is to buy 32 inch monitors. Otherwise I need to sit a bit closer.

 

Hope this makes sense and helps you out. Calculator attached.

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Yep I figured about 32 inch monitors/tvs would be the perfect size, trouble is no one makes any good monitors that size (apart from perhaps Samsung) that don't cost an arm and a leg and mounting them is trickier too.

 

I'm 30" from my monitors and I could in theory move them closer but I'd have to make some fundamental changes to my rig  which I can't really be bothered doing for a few extra degrees of FOV.

 

Thanks for sharing this is very useful for anyone who's starting to put together a rig.

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Yep I figured about 32 inch monitors/tvs would be the perfect size, trouble is no one makes any good monitors that size (apart from perhaps Samsung) that don't cost an arm and a leg and mounting them is trickier too.

 

I'm 30" from my monitors and I could in theory move them closer but I'd have to make some fundamental changes to my rig  which I can't really be bothered doing for a few extra degrees of FOV.

 

Thanks for sharing this is very useful for anyone who's starting to put together a rig.

 

Maybe one day when video cards can handle triple 4k 32inch screens it will be time to upgrade :)

 

My wife is 5'5" so 27inch is great for 179FOV as she sits closer. Moral of the story, if you are shorter you can get away with smaller screens.

 

No problem, my pleasure.

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Holy crap...my brain hurts after reading all that. :lol: I have triple 22's and im between 30" and 35" from them and the immersion is very good. That being said, I have my eyes on some 25" and 27" monitors that would make it even better.  :)

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Holy crap...my brain hurts after reading all that. :lol: I have triple 22's and im between 30" and 35" from them and the immersion is very good. That being said, I have my eyes on some 25" and 27" monitors that would make it even better.  :)

Using the calculator, if you are sitting an average of 32.5inches away you should have your monitors at a 33 degree angle and your max FOV in game would be 99 to get a realistic sized cockpit.

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I set it to 99 just for S & G's and im basically sitting on the hood..lol Normally I run at 113 and it gives me full view of the windshield and the top portion of the dash. With it set at 99 I lose a good portion of the right side windshield and it just felt "weird"

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I set it to 99 just for S & G's and im basically sitting on the hood..lol Normally I run at 113 and it gives me full view of the windshield and the top portion of the dash. With it set at 99 I lose a good portion of the right side windshield and it just felt "weird"

I reckon it'd be weirder to drive you car from the back seat...  although you'd have a great view of your side windows.  I'd recommend sticking with it for a bit as you could potentially see your lap times start coming down because you can judge movements from the correct perspective.  Almost everyone I've talked to about this has seen improvements in lap times once they started using their correct FOV.

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sebj,

 

Could you give the link of the thread you got this from ?

 

David is in a few of the FOV discussions,  I have been looking for a particular thread lately, and that may be the one.

There is a pic, a few pages from the last that has a big screen with progressively smaller screens marked with outlines.

 

Thanks

 

P.S. If it is the one I have been trying to find, then it needs to be linked in this forum anyways.

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sebj,

 

Could you give the link of the thread you got this from ?

 

David is in a few of the FOV discussions,  I have been looking for a particular thread lately, and that may be the one.

There is a pic, a few pages from the last that has a big screen with progressively smaller screens marked with outlines.

 

Thanks

 

P.S. If it is the one I have been trying to find, then it needs to be linked in this forum anyways.

 

 

This?

 

http://www.silverball-magic.com/my-stuff/Field_of_View_Explained.pdf

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sebj,

 

Could you give the link of the thread you got this from ?

 

David is in a few of the FOV discussions,  I have been looking for a particular thread lately, and that may be the one.

There is a pic, a few pages from the last that has a big screen with progressively smaller screens marked with outlines.

 

Thanks

 

P.S. If it is the one I have been trying to find, then it needs to be linked in this forum anyways.

http://members.iracing.com/jforum/posts/list/1330466.page

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I have a question for you guys, what's the easiest and cheapest way to measure the angle of the side monitors. 

 

I have been roughly calculating it but I want something more accurate and don't really want to have to spend any money on something I'm going to use once.

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I reckon it'd be weirder to drive you car from the back seat...  although you'd have a great view of your side windows.  I'd recommend sticking with it for a bit as you could potentially see your lap times start coming down because you can judge movements from the correct perspective.  Almost everyone I've talked to about this has seen improvements in lap times once they started using their correct FOV.

I wouldnt say im driving from the back seat really. My position in car is similar to where id be if I were in a real stock car (give or take) I actually cant see out the passenger side window at all from where im "sitting" (See picture below) That being said, im not resistant to change and it couldnt hurt to at least give it a go. I'm all for whatever will make me faster. :)

 

20130828_200719_zpsfc0278d1.jpg

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If you're happy with it just race that way.

 

could you post a picture with the suggested FOV so we can compare it?  I think it looks a bit small, wondering how it would turn out.

cheers

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I have a question for you guys, what's the easiest and cheapest way to measure the angle of the side monitors. 

 

I have been roughly calculating it but I want something more accurate and don't really want to have to spend any money on something I'm going to use once.

 

You need something with the angle you require to at least MacGyver a working angle tool.  I used my miter saw. It has angles on it for cutting and I used my adjustable angle tool to measure out 55degrees which I could place against the inside of the two monitors. If you had this you could even cut something out of cardboard. Or buy a cheap protractor at your office depot, draw out where your angle is on some cardboard and cut out the piece to place against your monitors. Dont know if you could do it any cheaper.

 

If you want, send me the angle you need, I can draw it out on a piece of paper, scan it and send it to you in pdf which you can cut out. !

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Damm*t Seb..lol I tried it and I was kind of indifferent. It wasn't until I flipped back and forth between the pics that I really saw the difference. The 99 is a lot more "1:1" I'm gonna use it for a while and maybe even try to find some bigger monitors. The 22's are great but everyone loves more real estate. :) Here's the pics btw..

 

113 FOV..

20140117_205705_zpsxwzukjaj.jpg

 

99 FOV

20140117_205633_zpsvgcpnwlz.jpg

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Nah, wasn't the one.

 

I found it at work one night and didn't think to write it down.

 

Thanks anyways. If I ever find it again I'll put it up in here.

It deals more with the actual total numbers more than the applied angle.

 

They are all good reads from him though.

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Either I broke your calculator or I don't know how to work it properly (more than likely). I play on a 110" projection screen with a width of 95.9 inches wide viewing screen. It has a height of 53.9 inches viewing screen. I sit 89 inches from the screen with a eye level of 21 inches from the base of the viewing screen. I'm looking for a 1.1 ration with my bad inputs in the calculator I end up with a steering wheel that is around 2 feet wide am hoping to get close to a life size on the track view.

 

I'm wondering if anyone that knows better than I am willing to do the math on this one it would be greatly appreciated. seating distance can be changed a bit, I am unable to move closer because the top of you head will clip the bottom of the screen. But back by about 1-2 feet however this is the exact viewing distance to fill the frame of my glasses.

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I believe you need to set your FOV to 57

2 feet closer requires an FOV of 73

2 feet back requires FOV 46

1 foot back requires FOV 51

 

since you sit so low you may want to lower your view such that the horizon matches your eye level or whatever feels comfortable there an about. You can also set driverHeightAdj=-0.020000 in the app.ini file to lower the seating position so you can see more of the dash, if at all possible.

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