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UE4 rendering issues while using nVidia VXGI


UE4 rendering issues while using nVidia VXGI

Hi all,


I've recently integrated nVidia VXGI for the Unreal Engine 4, in order to test a couple of scenes using the Vive.


But the rendering has some issues, since I notice that, as soon as the VXGI is enabled from the Post Process Volume, the VR rendering gives me no shadows on the left eye and the proper shadows on the right eye, making the experience quite uncomfortable.


I don't know if this is related to VXGI specifically ( probably ) or the Vive has something to do with it, but I would like to solve this issue so that I'll be able to use dynamic GI in VR.


Anyone has the same issues and possibly a solution?



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Vive Staff

Re: UE4 rendering issues while using nVidia VXGI

[ Edited ]

Are you using stereo instanced rendering? VXGI eats a ton of resources, have you looked at your resource usage? Generally speaking VXGI isn't very suitable for VR (at this moment) and typically works best with deferred rendering. 

- David R

Technical Specialist; San Francisco, CA


Re: UE4 rendering issues while using nVidia VXGI



Thanks for the reply. Luckly a good samaritan helped me solving the issue, so now I have shadows working properly.

Yes, I'm using stereo instanced and you're right, even with a very simple scene the FPS drops dramatically, so I think that the next gen of GPUs might be able to handle VR.


The main reason for me was to be able to handle the time of the day but also be able to put realtime objects inside the scene, to basically build the interior of a house in realtime.


I tried LPV in UE4, but the results are quite bad, so I guess that the alternative would be to not use VR with VXGI, or to use VR and fake GI somehow, or have different lighting scenarios ( day / night maps ), but the issue with the realtime objects will still be there...

I'll try come up with an alternative Smiley Wink