Can anyone explain why the FOV Tangent Multiplier has such a significant impact on FPS? I have the Quest 2 and a 3080, and setting the FOV to 0.6;0 gives me such a dramatic increase in FPS and no stuttering. If this setting is only to mirror the lenses to the 2D screen, and it impacts FPS so much, why not eliminate the mirror to the 2D screen altogether… seems like that would reduce the amount of work the GPU would have to do and increase performance in VR.
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It reduces the field of view in the actual headset. That’s why your experiencing much better frames. Just depends how much you can tolerate, flight at night is fine but in the daytime it’s slightly restricted but the improved performance is worth it.
Its my understanding and experience that it only reduces the FOV on the 2D screen, not in the headset. Hence, the .6;0 setting makes it very skinny and distorted on the monitor, but its not noticeable in the headset at all… thats the premise to my question… because it makes such a smoother experience in VR with that setting, why not have the ability to NOT mirror to the 2D screen.
In my Oculus Rift CV1 changing this to E.g. 0;0.9 have an impact on my field of view inside the headset by adding black bar on top and bottom (cinemascope like), which is expected obviously.
Maybe something is different in the Quest 2… i’ve heard that from other people as well, but thats whats strange is I don’t see a reduction of FOV in the headset at all… only on the screen. But I get quite a boost in performance with this lower setting. According to the dev documentation its only supposed to impact the mirror to the screen… [Compositor Mirror | Oculus Developers]
Adjusting Field of View (FOV)
The default FOV used by Compositor Mirror doesn’t show as much content as is seen in the headset. To increase it you can use the FovTanAngleMultiplier option. The following example shows the recommended settings to best match the Oculus Rift’s FOV:
I have an Ocukus Quest 2 and this setting does affect what I am viewing through the headset, change it back to 0 then change it to 0.50 and you should notice a big change in the view (ie much more limited)
First value is for horizontal rendering, second is for vertical. They apply in the headset, the tooltip is wrong. I use fov 0.85;0.75, as i find these values are almost visually imperceptible in the headset and they provide a nice increase in fps, because you actually have to render only 0.85*0.75=63% of original pixels. Regarding the usual recommended value of 0.6;0… it is visually bad and it distorts the image.
Try with values of 0.85;0.75, or 0.8;0.8. Do not go below 0.7 in horizontal because it introduces distortion and messes up your eyes, at least in my case, it feel like going crosseye.
Well… this is what is strange… I do not see any difference in FOV in the headset. I only see a drastic distortion of what is displayed on the 2D mirror to the screen. I don’t understand how people are getting different results for modifying this setting (some seeing it in the headset also, but some not)… but it seems to be a super magical trick to get way better VR performance… thanks for all the feedback.
It is impossible to not see a difference in headset when you set a horizontal fov of just 0.6. Perhaps, the setting does not stick, or you do not set it right?Do exactly as this to make sure it works. Open ott, open oculus home. Close oculus home. Set the wanted fov in ott and press save. Open link, and with this, oculus home should be opened automatically. Profit. Take note that for the fov change to work, oculus link has to be closed, and oculus home has to be closed aswell. You only need ott open and the oculus service started.
Its possibly not working. If you’re using the tray tool then don’t always assume the settings are actually taking effect in the headset. I find the tray tool to be a bit unstable and hit and miss, which makes using it for calibrating things too unpredictable for me. The debug tool does similar things and is more reliable. Thats what I found anyway.
You’ll definitely know when its taking effect as you’ll see what look like black shutters on the periphery of your vision when wearing the headset. If you don’t notice that then you can be sure the setting isn’t actually working.
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