FIXED: VR disparity problem

Just realized why my eyes and head ache after working in TD with a Vive Pro2 headset. There is a disparity problem with the left and right image rendered out of the openVR TOP. My Steam/Vive setup reders fine, and the desktop VR view is correctly portrayed. Rendering the Pallete TDVR, the disparity problem shows in the HMD by the horizon rendered at different height in L and R screenshots compared to the desktop overlay. Same results with networks I have built from scratch. If I tilt one of the cameras about 1.5 degrees it seems to be corrected.

Win 10, current build, same results in a 21 build. Current Steam and Vive software.
Unreal 4.21 displays correctly, for reference

I would deem this as a pretty urgent issue if this is a fault that is not local to my machine but something people have been working with for years.
It really messes up eyes and creates headaches, since it it just within the range of eyes to forcing to correcting it.

I posted this at the help group and Michel Didier mentioned he had logged an issue.

Regars, Boya Bøckman

Hey @lBoya

Thanks for the report.

This is logged for a developer to test and look into it.


Hey @lBoya,

unfortunately I could not replicate this issue, neither with a Vive nor a Valve Index.
To make sure I get a truly level output, using a Teansform CHOP I set all the rotation channels of the headset to 0 and the horizonline perfectly lines up in headset as well as the VR view.
Unfortunately, I don’t have access to a Vive Pro2.


Hey @lBoya,

@daniel.dalfovo reported that when negating the proj[LR]_m12 value of the left and right eyes projection matrix, this fixes the issue you are seeing. We are working on a general fix for that in the meantime.


Hey @lBoya,

a fix has been submitted and will be included in the next release.

Thanks for pointing out this issue.

Thanks @snaut!.
Great to see you and he community i Berlin.
Take care, Boya

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