Reducing VR head tracking shaking and distortion

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Reducing VR head tracking shaking and distortion

jntracks
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Joined: Sat Jul 10, 2021 2:42 am

Post by jntracks » Tue Jul 13, 2021 2:15 pm

Hey everybody,

Just getting started and having fun with this thing, particularly interested in the TFTC.
I'm using RiftS. Seems to be working generally pretty well, all things considered. Really amazing work!

I think the answer to this is probably "no" or "it's incremental; we'll see" but I'm wondering...

Is there any thing to tweak that could reduce the shakiness and geometry distortion of the head tracking when I look around.
I suspect these are both related to the same thing since it's a game engine that wildly pre-dates being able to do anything like VR is today. It seems like the cockpit around me shakes quite a bit as I turn my head. Sometimes it's worse than other times. Like generally flying around is pretty ok, but sitting in the hangar before taking off it's really shaky. I also notice that the farther from center I turn my head the more twisted/stretched the geometry starts to become. And the cockpit starts to slide left or right a bit. This also happens really strongly in any external cam mode, like when I press space to enter hangar.
This feels like something related to Z clamp, if that's the right term. I remember from the Duke Nukem 3D days looking up and down caused a stretch because the engine wasn't really designed to handle that right. (wait for Quake)


So anyway, to summarize: really great work, it's wild! Is there any detail or setting to tweak to maybe get things more smooth, or setting to allow the head tracking to distort the geometry less?

Thanks!

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blue_max
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Post by blue_max » Tue Jul 13, 2021 3:14 pm

We're trying to figure out where the shakiness comes from -- not everybody experiences that. Duke Nukem had this distortion because it wasn't a true 3D engine; but this one is. So, maybe there's a bug in the 3D reconstruction code that we need to check. To reduce the jitter, you can reduce your resolution to increase performance. You can also try the following:

viewtopic.php?f=36&t=12490
viewtopic.php?f=36&t=12827

jntracks
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Post by jntracks » Tue Jul 13, 2021 4:18 pm

Thanks for that, I did play around with the rendering setting a bit. It can be tough to interpret when I'm having a performance issue since the reprojection (Oculus ASW, in this case) can hide it. I am playing on a RTX 3080 so I imagine resolution isn't an issue.
From what I've read here, the geometry is calculated on the CPU but resolution would be GPU based. So this might be my 7700k if performance is an issue.

I actually set steam to 200% res scale for some extra clarity and all still felt like it was performing the same while looking nicer. Do you think this is because my 3080 is doing just fine? Maybe the issue isn't GPU headroom?

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blue_max
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Post by blue_max » Tue Jul 13, 2021 5:04 pm

I think you're correct on all accounts. But I still think you could temporarily lower down your resolution in SteamVR to, say 960x1080 pixels per eye, just to see if that helps fix the jittering. What VR headset are you using?

DrFortran
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Post by DrFortran » Tue Jul 13, 2021 6:12 pm

XWA ignores the GPU. I am also playing with a 3080 (10th gen i7), and I'm at 50% SS for the heavy missions. Please use fpsVR to find out when your CPU can't push it, i.e., enable the overlay in the HMD and observe the CPU graph.

Edit: Valve index HMD

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m0rgg
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Post by m0rgg » Tue Jul 13, 2021 7:51 pm

For Oculus I recommend Oculus Tray Tool, it will help you disable ASW to observe real performance.
Also, it's a very convenient way to enable the in-HMD HUD that will give you the real framerate and render time.
Alternatively you can also display performance in-game with SteamVR frame timing.

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