What exactly does the reprojection option in the VR settings do?

[Mayc7672]

Hello, a quick question: what exactly does the reprojection option in the VR settings do? Is it an alternative proprietary reprojection system to the one used by the headset, or is it a system that helps improve the reprojection of the headset we are using?

thanks

[stekusteku]

Basically nothing.
MSFS can provide some additional information to headset software, but such software from various vendors rarely use this information. You can search for a post from mbucchia on this subject.

[Michail71]

Do you know if Pimax does? They are big on supporting MSFS in general.

[stekusteku]

I don’t now for sure, my bet is;
99% no support for motion vector
90% no support for depth
You can search the forum for the post on this subject by mbucchia.

Do Microsoft/Asobo just not care about VR users?

Explanation by mbucchia: Q: What is the motion reprojection setting in Flight Simulator VR settings doing (“Depth and Motion”)? A: Short answer: it does nothing today. Long answer: it implements something called application-assisted motion reprojection, also called AppSW by Oculus. It requires your OpenXR runtime to implement a feature called XR_FB_space_wrap, which as of today, no runtime implements (not even the Oculus one - the only implementation of AppSW today is for native Android apps…

Pimax - Microsoft cooperation is 99% marketing only.

[Michail71]

Motion vector actually resets itself back to depth in the settings menu.

[mbucchia]

@Michail71

Do you know if Pimax does?

Most runtimes will make use of the depth buffer to assist reprojection, though 1) how effective it is varies quite a lot and 2) it may reduce raw FPS as well (it tends to increase GPU memory utilization and bandwidth). The only that I know for fact won’t make a difference with is Virtual Desktop (whether via VDXR or SteamVR OpenXR).

PimaxXR (and Pimax OpenXR) does use the depth buffer, but I’m not sure to what extent it actually helps. If you don’t notice any difference with it on, then you’d probably better disable it.

No runtimes supports the “depth and motion” option.

[franco4gamin]

this might help…

What Is Reprojection in VR? - In-Depth Guide with FAQs, Tips, Advice, &...

[Michail71]

@mbucchia

PimaxXR (and Pimax OpenXR) does use the depth buffer, but I’m not sure to what extent it actually helps.

I only tried briefly as I’m now getting such good performance on DLSS Performance with the F preset I’ve stopped fussing and take the higher frame rates. But subjectively it felt to me like the prop may have had slightly less motion issues.

[mbucchia]

Depth-assisted reprojection should only make a difference with head motion, not scene motion, so it’s most likely a placebo. One thing to pay close attention to would be the frame of the plane as you move your head (especially translations, not so much rotation). For example moving your head back and forth forward or sideways. Depth-assisted reprojection should make the frame of the plane less juddery.

[Michail71]

I suspected it was placebo, thanks for confirming!