Removing "unused FOV" - free fps?

User Support Hub Virtual Reality (VR)
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(You can corroborate this yourself by peeking under your HMD into the desktop screen)

Not an expert in VR at all, but it seems like the scene that the app renders is around 50% wider and taller than what we see on our HMD screens, this makes sense to some extent as VR relies on reprojection and the device will keep the 90hz while rotating your head by projecting the scene provided by the app, so this extra buffer can help the HMD project on rotation.

I think sudden movements are rare in MSFS, you can greatly benefit by reducing this buffer and I see ~60-100% increase in FPS by cropping this ā€œUNUSED FOVā€

On oculus, you can crop this ā€œUNUSED FOVā€ on oculus by changing ā€œMirror FOV Multiplierā€ on oculus tray tool to a number lower than 1 and press save ( same feature in Oculus debug tool called FOV- Tangent multiplier), make sure to reenter VR (ctrl tab twice) after setting, you need to do this every time you start the oculus service:
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If you run this value too low, youā€™ll start noticing that during head rotation oculus ends up more frequently running out of scene to reproject from, leading to black borders on the edges. I would recommend doing 0.8, 0.8 and lowering if your comfortable seeing black bars during sudden head movements, which IMHO is not really annoying. 0.8,0.8 would reduce pixels on screen to 64% which could be a 50% increase in performance.

If you do this, the simulator is super playable, even on mid range gpus. Iā€™m using a 2060 max q laptop, quest 2, 100% scaling, settings to mid, forcing ASW to 30hz, and can read my controls while with super-smooth motion (asw is awesome). Youā€™ll see artifacts with ASW but thatā€™s fine.

  1. Does anyone know if this ā€œUNUSED FOVā€ is accounted for the resolution we see on the scaling slider, if I set 1800x1800, does it mean that the game is rendering ~2500x2500 and matching my device pixel density or that the game is rendering 1800x1800 over the whole scene and my device is not really running at full resolution? (Maybe this would explain why going for 1.5x supersampling is delivering so good results for some people)

  2. Is this also an issue for non oculus HMDs? Maybe they could benefit from this trick as well?

  3. Am I missing something here?

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It works well. Been using it and it is a really good trick. Even with black barsā€¦ you will end up forgetting them after a while.

Really not sure about what is happening with resolution. It is much lower on MSFS at 100%, that is why is working so well. Not sure what happens after it is rendered.

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I was playing around with this last night and it does help. One thing to note though is that it only works with the Oculus debug tool for inside the headset. The same tweak on the OTT tool only effects the mirrored screen on your monitor.

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Can you post a screenshot of the settings changed in Oculus Debug Tool? Thanks!

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I tried it in both last night and it worked from both. There is a ā€˜saveā€™ button IIRC on the tray tool that you have to click to actually apply it.

Also, itā€™s very weird that this is doing anything ā€“ the FOV multiplier is only supposed to affect the mirrored display on the 2D desktop monitor. The same is true of the FOV stencil. The fact that these are showing up in the HMD is almost certainly a bug in the Oculus software driving it. A useful bug but a bug nonetheless. I suspect this is due to the way Link is capturing the image, and I doubt it works for Rift S or CV1 but will test when I have time today. It definitely wonā€™t work for non-Oculus devices, though. That FOV multiplier is part of the Oculus runtime; it isnā€™t present for anything else.

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I think that this also helps with rift based on some peoples comment.

I suspect that it might also be an issue for other HMDs just bc I havenā€™t seen anyone posting fps close to the FPS we see on oculus (30+ fps at 100% scaling on 2060 max q after cropping fov), but that could be many other things.

I Wonder if people using other HMDs also feel like the FOV on the 2d projection is wider than the HMD.

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One thing we know for sure. The Oculus implementation is bugged and not optimized properly. I believe the same is true for the SteamVR. We are using beta versions of Oculus software to actually get it to workā€¦ this says a lot. Asobo was going to release WMR first with a focus on the G2 and they rushed to get support for all headsets before Christmasā€¦ Great. Not complaining, I am enjoying it now (after weeks of tweaking) :slight_smile: You can clearly see the potential and if you ignore the bugs it is clear that the performance/quality will be great in the near future. Hopefully we will see updates and improvements soon, from Asobo, Oculus and Nvidia.

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Just got an update pushed to my oculus PC app (showing v25 now). Also Nvidia released a new driver today. Letā€™s see.

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Really interesting! Anyone know if something like this is possible for WMR/G2?

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Any Improvements Chief?

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Hard to tell. This new Nvidia driver runs exactly the same as the 457.30 I was using. Canā€™t tell any differenceā€¦ I will keep the new on for now. Canā€™t find release notes for the Oculus V25, not sure what has changedā€¦ it is running smooth on my system - recommended settings 90Hz + ASW 30 + FOV trickā€¦ I am getting -60 headroomā€¦ Noticed that when headroom is lower than this, ASW will struggle.

I am running 100% render scale something like 1300x1300 per eye using FOV 0.75. Instruments are readable. Lots of settings on high, reflections, etc. A couple things on ultra. Terrain LOD at 50

Whole experience is a lot better, problably just placebo effect. :slight_smile:

BTW noticed that SteamVR was also updated. Also there are tons of people already complaining on Nvidia forums about the persistent stutters using steamvr :slight_smile:

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Yep same for me. I am using almost the same Settings by the way.

The most annoying thing for me is still the Cockpit-Judders of complexer Aircraft. I just cant get rid of it!

Thats why im mostly flying the freeware Savage Gravel. Works great!

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Savage Gravel is awesome. Performance is definitely much better simple planes.

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Hello, are you charging the FOV in the Oculus Tray Tool or Debug tool? If itā€™s the debug tool are you just adding 0.7 to the FOV Tangent Section so 0;0.7? Thank you!

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TrayTool. 0.8/ 0.8.

On the debug tool I believe you can click and change them indivially or just set 0.8; 0.8. Multipliers for both vertical and horizontal.

You can try different numbers and see what works for you.

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Thank you I shall give it and go and see what happens.

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Thanks for sharing.

Can you tel me what is your hardware configuration ( Processor, GPU)?

It may help me know if iā€™m same as you or closer to.

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I tried this and I canā€™t stand the seeing the bordersā€¦but it does eliminate the black edging in recordings when turning your head too fast.
So for the purpose of recording VR footage Iā€™ll set my to 0.90

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Same quotation here, any idea about WMR?

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These threads about FOV are the most important on this forum for VR Oculus performance IMO. On my 2060SUPER changing the FOV to 0.7/0.7 improves fps from 20 to a stable 33 at 90Hz refresh. If thereā€™s black bars when I turn my head I havenā€™t really noticed them.

Does the resolution and settings of the 2d mirror make any different to VR performance? I have the mirror running at 1028x768 but havenā€™t set low quality because I want to fly 2d sometimes. Does it gain any VR frames if the 2d mirror is set to low quality 800x600 for example?

Also, is there any equivalent of the FOV Tangent when using SteamVR and/or VD? Playing wireless is great but itā€™s stuck at 20fps because of the lack of FOV tangent option.

Thanks so much for highlighting the FOV thing - total game-changer for me also.

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