stupid shadow artefacts on nanite landscape

poopipe

wtf is this and how do I make it go away? 
(it is not the thing with a solution in the video you just thought of)

UE 5.3.2
Hardware raytracing is disabled (which is why its not the thing in the aforementioned video)
Lumen is enabled
Landscape is nanite
Virtual shadow maps are enabled

It goes away when the landscape is not nanite (not an option, this is a world partition world and the map is quite large)

ta:)

Alex_J

just a guess, but contact shadows is turned off?

poopipe

yep. 

to add.. 
Behaviour appears to change in synch with mips in the virtual shadow map - there is actually a distance where the artefact isn't visible. 
The patterning of the artefact does look similar to the artefacts you get with two sided ray-traced shadows on nanite objects 

iam717

The comments here might turn up some solution. (not many)

https://www.youtube.com/watch?v=yZRa6cR91Tk

i looked a bit gave up.

Your recent post eliminated this solution:

https://www.youtube.com/watch?v=OM0yMr5B6n0

i might spam vid links with possible "solutions"

https://www.youtube.com/watch?v=yzfRMlA5dmU

https://www.youtube.com/watch?v=BCWThDhzImI  

poopipe

yeah - the first one isn't a bad shout but this is exclusive to nanite landscapes (watched the video with no sound so may have missed something.  I suspect it's got something to do with the geomegrty it chooses for shadows at a given mip as it only really appears  where the landscape has fairly high rate changes of direction. 

I'm gonna ignore it for the time being  - I've spent most of the last year trying to get a performant (and practical) solution to large world partition worlds working in 5 and  i just don't have the heart to start fighting with the renderer at the moment