I’m experimenting with the 5.4 preview build from the launcher, in particular the tessellated displacement we can have in materials again on nanite meshes now.
I’ve got the displacement working great with perfect shadows (Virtual Shadow Maps) while the displacement texture is static.
I tried applying a panner to the UVs of the displacement texture which works, except the shadows don’t seem to update in realtime, so they get left in place as the displaced parts of the mesh pan. When you move the camera in our out and the nanite meshes go between a group level and update then the shadows update again, but are then frozen in that new position.
I’ve played around with most of the shadow settings I know about and haven’t found anything that can fix it yet. Has anyone had success with moving displacement textures in 5.4 preview yet, or have any idea if this is something that will be addressed in the full 5.4 release?
If you’re not using VSMs of course, ignore me, but I believe they mentioned that that was a VSM cached page issue (dynamic displacement not triggering VSM updates). I think there’s a way to flush history more effectively, but I can’t remember the commands in particular.
You very well may have looked into commands like that already, but I’m curious how well different shadowing methods as a whole would adapt to nanite dynamic tesselation.
Thanks for the suggestion. I am using VSM and I remember them having issues with WPO displacement, even on static objects, when they were first introduced but I think that has since been resolved.
But I am hopeful there is some command that I’ve missed that changes how VSM are updated as I’m sure it’s a caching feature as you suggest.
I tired ray traced shadows as well but they seem to just ignore to displaced geo.
EDIT: I just found the toggle for Shadow Cache Invalidation Behavior and that has completely resolved the issue, thanks very much for pointing me in the right direction!
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Hello Katanalevy! I think I might be having the same issue, I have a geometry with displacement Nanite that is also in motion with a panner. By any chance, could you tell me where to find this toggle to fix this issue? I am searching for it but can’t seem to find it 
Thanks in advance!
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Sorry for the late reply. I wasn’t back in here in a while.
If you didn’t work it out already you will find it by searching for “Shadow Cache Invalidation” in the details panel for any static mesh you have placed in the level.
Hope that helps.