Unity 2020 bug: Inaccurate Rotation when Looking Around & other incompatibilities

“a Pimax->SteamVR bug that only manifests in 2020+.” is absolutely true (at least on my machine), so that’s why I wrote that. In case that’s not clear, what I mean is “something in how Pimax & SteamVR communicate” not necessarily that it’s Pimax’s fault/bug, so definitely in agreement with you…

Again, I just want to get this in front of whoever the right people are. The exact same setup works perfectly fine in 2019. Honestly this whole plugin thing is a mess. As soon as the Index controllers natively work in OpenXR, this’ll be a thing of the past. The question, in the event this isn’t addressed by either party, becomes how many products get created/released on 2020 using SteamVR before that happens?

Anyway thanks for jumping into the conversation!

How Pimax and SteamVR (runtime) communicate is completely opaque to the (SteamVR) app and does not depend on this app. In other words, if there was a problem at this level it will manifest in every app/engine.

Just out of curiosity, does it happen in native or PP mode or both?

Didn’t recently test with PP, but I think I did back when I first documented the bug in August and it was still happening. I’ve uninstalled 2020 for now so I’m disinclined to get another test environment set up. But I’ll be sure to drop an update here next time I take a dive into 2020.

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Hi MagiJedi,

Have your problem been solved?
If not, please submit a ticket through the following link, where our technical support team will provide individualized solutions for you.


So I finally found someone having the same problem.
I posted a new thread a few days ago about this bug.
Have you found a resolution by any chance ?

Not a solution, but a work-around.

So, first of all I’m now using Hurricane/Hexabody plugins, so depending on your SDK the steps/components might differ slightly.

You should have a component on your camera for pose tracking (tracked pose driver in my case) with a field for the Pose Source, which is defaulted to Center Eye - HMD Reference. Switching that to Head works. However, I occasionally have odd performance in-editor Play Mode unless I switch away from/back to Head. Not sure if that happens in a build as I’m knee deep in prototyping these last few months and haven’t bothered.

Would really love a native solution, but every time Pimax comes up, Unity either ignores the question or says it’s not supported.


Ah Thanks
I’m not a developper but I experienced this bug while playing.
I guess I’m out of luck.
I really hope it gets addressed at some point, it really makes games unplayable.

Oh sorry I misunderstood. Can you list the game(s) you’re having trouble with? Should be worth at least documenting it somewhere.

No worries.
I first got this bug when I updated Blade and Sorcery to version 9.1 where they “Updated to XR plugin” (quoting the patch notes). The bug got resolved in version 9.3 when they “Removed Unity XR plugin (hopefully fix a rare crash / black screen)” (again, straight from the patch notes so I don’t really have more information).
More recently I’m having this problem in the ValheimVR mod : https://www.nexusmods.com/valheim/mods/847
I reached out to the dev on discord and he told he’s using built-in OpenVR and Unity stuff so he’s not quite sure there’s anything he can do about that.
I did comment on you github issue, hopefully Valve will take notice.

If you reach out to the Valheim mod folks again, you can pass my suggestion along. If they implement that trick, it should work for Pimax users.

Blade and Sorcery U10

Hard Bullet

Sep’s Diner

Walkabout Mini Golf


Museum of Other Realities

Walkabout Mini Golf

Were also not working from a post on the pimax subreddit.

Shame to see Pimax being snubbed by developers. We need OpenXR stat.

This way its nit up to them to specifically fix any one headset.

The issue with OpenXR is the lack of Index finger tracking compatibility. Hopefully they get that resolved soon.

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“I hope you can make this clear to your team so you don’t suddenly find your customers unable to enjoy newer games in the next few years” damn this problem is older than i tought,and you were spot on,ive been annoying devs for like 2 months to fix newly updated or released unity games,only blade and sorcery and table tennis actually did,with the head reference fix,but its in literally every unity game that is coming out now just bought after the fall same thing,and in the same day i tried ab aeterno play test and the exact same annoying bug,apart from the other many unity games that have it pimax 180 degree bug on unity games - YouTube made a video some time ago to show the bug,this sucks.

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please post this in bug in the afterfall bug reports on steam

the unity fix should be :
In case any developers come in here wondering about the issue, I’ve managed to isolate a workaround.

If using Unity XR or any interaction systems dependent on it, the camera object has a Tracked Pose Driver component on it, which defaults the “Pose Source” field to “Center Eye - HMD Reference”.

Changing Pose Source to “Head” should alleviate the issue with Pimax.

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And make sure to credit DudeSoft Games for the fix :slight_smile:
Just kidding that’s absolutely not necessary.

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Has After the fall this bug too, then?

update from the steam forum for after the fall, first time i’ve seen any acknowledgement from them:


HOWEVER, I dont see it on the bug wall they have linked in the latest known issues patch notes: https://vertigogames.atlassian.net/plugins/servlet/Wallboard/?dashboardId=10003


Against is the latest release with this bug ugh

This bug has been fixed in After the Fall. I don’t know at what point exactly, but I had to use parallel projection before. I just tried it again without parallel projection, and it works now.

You do get double vision during the loading screens sometimes, but otherwise After the Fall now seems to work perfectly without parallel projection.