Incorrect Shadows

Development Rendering
, , , ,
1

Hello,

I am having trouble to get usable results with some assets. In the next image you will see how the grass does not get a “proper” shadow on it from the white columns on the right part of the image. most of the upper part of the grass is Lit as the sun was hitting directly on it, as you can see in the left part of the image :

image
image1674×808 281 KB

:

this is a foliage actor, the asset has a material with masked and WPO on it. I already watched this video Troubleshooting FOLIAGE issues in Unreal Engine - YouTube and just in case, eventhough the problem is not the same, I tried the “evaluate world position offset” checkbox wich makes no diference (even with a blueprint and foliage actor) and also the “foliage.forceLOD” console command

I also checked what happens when using the asset without foliage tool, and the results are exactly the same, so I guess Foliage is not the problem. I also tried to see if the material is the problem, so I created a new material just with the mask and a grey color, nothing else…the results are not promising, since it also looks really bad:

image
image1671×766 165 KB

So by elimination, it only remains Lumen, I guess, as the source of the problem. Any ideas in how to get a more natural shadows casting on those grass assets? Like the result from the path tracer?

image
image1645×768 172 KB

thank you

2

So I found out that the asset I was using, has the planes placed in a way that Lumen does not like…so I tried an asset from megascans…here the part receiving shadows and the part where the sun is hitting look more correct:

image
image1650×797 288 KB

BUT I got a the shadows flickering now…this material has no WPO, is just Masked foliage material. Anyway I tried again the solutions for funny shadows on foliage from the video on my last post and again it makes no difference. If I disconnect the mask from the material, the billboards look correctly shadowed and without flickering, but when I use the mask the flickering is there. Here a small video where you can see the shadows flickering:

so, Is there any Lumen setting or maybe texture or material setting to improve this result?

3

I found that r.Lumen.ScreenProbeGather.Temporal.DistanceThreshold = 1 reduces the noise, but it is still there and very noticable…does anyone know any other tweaks to make the noise flickering less obvious?