normals on mehses diferene between CPU and XPU

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I;ve run into similar issue a while ago which was then resolved by increasing maximum samples for HDR dome light. But seems like it does not work any more.
Increasing sample have no effect and weird artifacts are rendered. Meshes are clear when using CPU rendering. Attaching example of difference between these. Any ideas how to handle this issue at the moment?
Also to notice that I managed to get same artifact using karma physical sky as well so seems like there is something different happening between CPU and XPU when rendering these.
Need this sort of figured out to start rendering project ))
Thanks for any help!

Edited by Mirko Jankovic - Sept. 12, 2024 06:32:08

Attachments:
CPU.png (506.9 KB)
XPU.png (379.6 KB)

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Hmm to make things wierd.. I was testing around and seems like it renders fine until I turn on additional grass instancing node for environment.
I have ENV setup that is exported as USD and then layered or environment rendering.
There are couple nodes for trees flowers and grass... Now when I turn off two grass instancing render nodes it renders fine, same as with CPU. When I connect back those two or evne one of those additional grass nodes it breaks. Also those nodes are same as others already used in just different attribute map used for placing grass.
Is there a chance that there is simply too much of geometry at some point?
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https://youtu.be/zyCSlDw6_PE [youtu.be]

Seems like there is problem with number of grass that I instance at some point When I reduced that number drastically, number of grass meshes instanced in these two nodes it was fine. So I guess there is some limit after all, or maybe different method to sort out grass in the scene.
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Do you suspect a bug? Are you able to create a repro scene? If so, feel free to submit a bug report
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Well still not sure if it is defined as a bug or GPU limitation.
At some point when number of instanced grass geometry exceed some point those artifact starts appearing. When rendering with CPU it is still fine, with XPU it is not ok.
I was wondering first if it is something like old issue with HDR sampling where I had similar artifacts but increasing HDRI sampling to something like 100000 solves it.

Thats why I'm not sure if it is bug, GPU limitation or just a matter of some settings that I missed?
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