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VR shadow issues in right eye

Development Discussion VR and AR Development
#1

I haven’t seen this in more than a year and it was a little different.

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I’m on 4.9.2, and the right eye has a checkerboard grid with and without shadows. Oculus 0.7 358.70+358.78 and 0.8 358.78 on a 980 ti on windows 10 64-bit. I clean-reinstalled everything but the OS. I should probably mention that I also had installed a Radeon 7990 which shows no such issues.

Did anyone see anything similar recently? I was thinking a display issue because I see the shadows are rendered just not displayed correctly, almost as if they are following a z-depth buffer with insufficient precision and thus parts of the shadows are overlayed and parts are drawn before the final image.

Edit: It only happens with raytraced distancefield shadows so it must be a bug. Will try to rollback drivers as I distinctly remember this was working fine in VR.

#2

I think the feature is not supported yet for VR, I tested it back in 4.8 I think (for soft dynamic shadows) and the right eye had no shadows at all.

#3

AFAIK, like AtsK said this is not supported in VR at this point in time due to the high rendering cost associated with it.

#4

And yet he’s using it! He’s not complaining about latency… only that it doesn’t work :frowning:

#5

Well, it’s on a 980 ti on a highly optimized scene. Even VXGI works with 75fps :slight_smile:
As I said earlier, I distinctly remember using the DK2 and raytraced shadows so I don’t know. Besides, I can see them rendered just fine, even up-close, they are just flickering with this checkerboard grid on top.

#6

Point being that you’ve optimized your target system to be able to use the feature. The feature isn’t usable by developer choice. I think we should all be considered grown-ups and assume that we all understand that featureX is costly. But if your scene is designed for it, then it’s fine.

I get that it is a way for Epic to prioritize feature updates. It makes sense, since few users will actually be able to use it. But as a greedy self-serving jerk, I don’t agree with that method of prioritization;) Also, on a more serious note… Unreal is being used in more novel ways these days than just building traditional video games. For example, a large production studio might be trying to use it as a very high-fidelity previsualization tool. Part of that tool might want to use soft shadows in VR to best represent the assets to clients and fellow designers, knowing that their scenes must be carefully tuned to allow that. They might really appreciate having the option to turn on all the features when desired.

#7

I can report that at least for preview 5 of 4.11 Distance field shadows do work for stereo rendering… kinda.

Firstly for my setup running a 970 the average cost to update the global df for MY PARTICULAR SCENE is around ~5ms for both eyes combined as I have quite a few dynamic objects in the scene(could it be optimized so that it is done only once and shared for the second eye I am definitely not capable of saying). This could be close to 0ms if you have little to no movable dynamic objects.

Secondly my use case for this is not regular indoor lighting and I can see some artifacting further away form the lights in the form of big black squares(not visible for regular rendering, but they are more evident for movable objects), so this might not affect you, but be aware that you could run into this problem and when you do it is very nasty. I will play around with cvars a bit to see if that can fix it.

Thirdly, is the fact that rendering movable shadows (with softness which is basically free and AO on top) is actually cheaper this way if you have complex geometry (realtime shadows are generally still considered bad practice in VR I know).

The added cost of updating the global DF (not hitting 90fps) and artifacting I get with this makes it unusable for me at this time. Though in a blank project, where I tried it first I did get very exited thinking of the possibilities as I actually did reach the performance as there were no dynamic objects there and I could enable both DF shadows and AO. So this might be something to check out as it might just work for you :slight_smile:

#8

Oh adding to this the cheaper capsule shadows do not properly work either producing unusable artifacts: render at only specific angles otherwise pixelated or partially visible.