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

Ghogiel

Any development on this issue?  I'm at a new studio and they have exactly the same issue. 

Nanite landscape and HW raytracing off.  I initially thought raytraced shadows but it can't be. 

To be fair, the current prototype doesn't even make use of nanite properly on terrain so it's just looking ugly for no reason. Except maybe something performance wise where the way nanite renders and shadows helps in that department, but I doubt it.  

poopipe

development..?
Ignoring it has been a pretty effective strategy so far - I dont notice once there's grass and stuff 


Barring that artefact I haven't seen nanite landscapes do anything they shouldn't in terms of how the shadows look.  They do plenty of other things they shouldn't - like not load in PIE or not load in packaged builds unless you perform a set of weird rituals first - but visually they've been fine and certainly run better than the standard landscapes

Ghogiel

Alright thanks. Yeah, grass etc covers most of it but then the paths on the landscape are terrain. Some areas,  totally jacked with a bunch of artifacts other areas nothing massively distracting is happening 

poopipe

that looks pretty rough   My feeling is that it has to be a bug rather than a wrong setting so i'm hoping it'll come out in the wash. 
I've not checked whether it's improved on 5.4 as i don't have the emotional strength for another engine bump at the moment

Brunel

Sorry if this is so obvious nobody even mentioned it, but have you checked it with Lumen and RT off completly? I vaguely remember William Faucher posting a video about this exact artifact and I remember being able to solve it on a previous project involving nanite landscapes, but can't remember how. I'll try finding it...

Edit: Try this: https://www.youtube.com/watch?v=F3XSKXhIAuU

If that doesn't help, I definitely remember fixing this on a landscape object before, but long ago in like 5.1.1. Let me know if you wanna chat more about this and maybe we can find how.

Brunel

poopipe said:

that looks pretty rough   My feeling is that it has to be a bug rather than a wrong setting so i'm hoping it'll come out in the wash. 
I've not checked whether it's improved on 5.4 as i don't have the emotional strength for another engine bump at the moment

Just realised I necro'd this thread. Sorry! Hope you found a fix or if not, hope this helps.

poopipe

still haven't got a fix - and thanks for trying but that is the very video I was referring to in the first post. 
ignoring it is still working pretty well for me

Brunel

Ah man I'm sorry. I'll do some tests my side later and see how it goes, but glad you're able to ignore it.

poopipe

havent actually gone back to check that landscape but in a different project i found that forcing shadow cache invalidation on the landscape to static cleared up a load of crappy shadowing artefacts.  obviously not useful if you plan to animate your landscape in some way but I dont think that's a common use case