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Steku

Realistic field of view (FOV) and 3 display distortion

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Introduction:

As we know MFS2020 at its current state does not support 3 display configuration, with the displays set at an angle (placing you in the middle of your cockpit with the ability to look sideways using left and right displays). What is missing is simultaneous multi projection (like the one available in X-Plane or some racing simulators), allowing defining parameters for side displays (field of view, size, angle). MFS2020 allows however (with nVidia surround) using 3 displays as one super ultra-wide display (in my case 5900x1080 with 70 pixels for bezel correction). For proper display geometry, these 3 displays must be set in one row (not angled) pretending to be one huge flat display. This is not what we would like to have (would be great to be surrounded by the displays) but currently there is no way around it. If we attempt to place side displays at an angle, we will perceive the image geometry on the side displays far edges as distorted (stretched).

More on the projection geometry principles here (video by nVidia):

Here is my attempt to make the most of the 3 display systems, with the following goals:

- to have realistic field of view (FoV), the same as the real world one, important e.g. your judging speed or flare height when flying visually,

- to have as much as possible of the vision area covered by the image (to maximize the FoV),

- to avoid perceiving stretching of the image at the far ends of side displays as distortion.

Step 1.

Place all 3 displays in one flat row (to avoid perceiving the stretching et the edges as distortion) and as close as possible to your eye to maximize the immersion (maximize FoV – as much as possible of your field of vision covered by the displays). IPS displays will work best, no color distortion when observed at an angle. The image below appears as distorted at the edges as it should be observed from the eyepoint located 60 cm from the displays (see the diagram below), while the photo was taken from the eyepoint located ca. 2 m from the displays.

3-displays-front-view.jpg

3-displays-side-view.jpg

Step 2.

Measure the geometry of your “cockpit”: dimensions of your center display (diagonal, proportions) and how far your eye is from the display. The measurements on the diagram below reflect my setup, you will have different values for your case. 

FOV-diagram.jpg

Step 3.

Calculate FOV (horizontal one, using one of the calculators used by racing simmers):

https://andyf.me/fovcalc.html

FOV-calculator.jpg

In my case the resulting horizontal FoV with one display is 46 degrees.

Step 4.

Launch X-Plane with Cessna 172 G1000 and configure the single display Horizontal (Lateral) FoV as 46 degrees. X-Plane allows defining the FoV in degrees, while MFS2020 operates in zoom levels only. Observe the result. Make sure your eyepoint in the virtual cockpit is your normal position (look down or sideways to make sure you are “sitting” at the proper place). If you don't have X-plane you need to subjectively scale your zoom level in step 5, don't use my views, as the geometry of your displays and your real-world eyepoint location may be different.

X-Plane-Fo-V-setting.jpg

X-Plane-image-at-46-deg.jpg

Step 5.

Launch MFS2020 C172 G1000 and attempt to recreate on just one display the same field of view as the one you obtained in X-Plane (you should horizontally see as much of the cockpit in MFS2020 as in X-Plane - consider counting the visible buttons on the right side G1000) . In my case the zoom level was 85%, you will have it different due to different geometry of your display setup. Make sure you have your eye in the virtual cockpit in the same position as in X-Plane.

MFS2020-zoom-setting.jpg

MFS2020-image-at-46-deg-zoom-85.jpg

Step 6. (optional)

Consider lowering the zoom level a bit to have more vertical field of view. In my case I’m using additional 10-inch touch display to display my gauges (Air Manager with Knobster - see the first picture in this post), which effectively expands my vertical FoV.

Step 7. (optional)

Consider using TrackIR to look sideways.

 

Check the 3 images below, taken from the proper eyepoint. Can you see any sigificant geometrical distortion at the side displays (observe the apparent size and shape of the hangars and the pitot tube lenght)?

The image is rotated to present exactly the same view on all displays, in reality I should be rather rotating the entire plane to look at the hangars through front part of the windshield via centre display, left hand side of the windshield via left display etc. But for the demonstration I just rotated the view, instead of the entire plane - the principle and geometry remains the same. 

Center:

Center-view.jpg

Right:

Right-view.jpg

Left:

Left-view.jpg

 

For comparison below the left display when observed not an angle but directly, such effect you will have if you place the display at an angle to the centre display. This is the same image as the one on the picture above, but observed at 90 degree angle (perpendicular to the display) with apparent stretching. Can you believe that?!

Left-view-with-distortion.jpg

 

Summary:

The approach I’m proposing is not a substitute for implementing proper multi projection in the sim by Asobo, but it provides the best experience and immersion for me at the sim's current state. As you can see my setup is in temporary stage, to allow me experimenting with display placement, soon I will replace it with more permanent fixtures - assuming the negotiations with my wife will end sucesfully 😉

Edited by Steku
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Good idea/compromise. Thanks for writing this up. I'll link to it from my long article on distortions. 

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Great idea, unfortunately I don't have room to have my 75" screens all in a line!

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Seems like new bug discovered, welhen flying with ultra wide display config (one ultra wide monitor or several with nVidia surround) - blurry lights at night:

 

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You can mitigate this by running the sim in Surround in a window and pulling in the sides so they don't stretch to the entire length of the side monitors. This way you'd be using just half of your left and right screens, which kinda makes the whole purpose of ultra-wide a bit pointless.

I have a feeling my side monitors will be resting for quite a while : (

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Posted (edited)

The geometry of the setup I proposed in the original post eliminates the apparent stretching at the edges, however such geometry doesn't provide the view by the side widows (multi projection must be implemented by Asobo to allow this). You have to have all displays in the flat row simulating one flat ultra wide display, the apparent stretching at the edges will by compensated by the angle/perspective at which you observe the side displays. 

The method you propose is also not helping with the blurry lights, I just received a report from the user on another forum, that blurry lights are plaguing not only ultra wide resolutions but also 4k and other high resolutions. 

Edited by Steku

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it's in the pipeline, that's great news 👍

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