UE5 Landscape Jagged Triangular Shadows

Development World Creation
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1

Hello!

I recently ran into an odd issue with landscape shadows. At certain angles and distances, the shadows look triangular and jagged and ruin the game.

Screenshot 2022-05-10 162102
Screenshot 2022-05-10 162102566Ă—964 310 KB

^ Landscape in shot is smoothed and not steep.

  1. The shadows are the exact same size as one face of the landscape (could be a coincidence, but probably not)
  2. The issue appears to only happen on the landscape.
  3. I can remove the issue if I disable Virtual Shadow Maps and revert back to old Shadow Maps, but that creates other, worse issues.
  4. My scene uses all dynamic lighting with the Ultra Dynamic Sky plugin (outdoor environment; static lighting is not an option as far as I know).
  5. I’ve tried tweaking cascade shadow settings in the directional light and I couldn’t change anything.
  6. I’ve tried tweaking lighting settings on the landscape and again, nothing.

Does anyone have any idea as to what is going on with my landscape?
Any help is greatly appreciated.

Thanks!

2

UPDATE:

  1. I tested it in a default unreal level and the issue is still there, so I don’t think it’s an Ultra Dynamic Sky issue.
  2. I found a mega-thread (Dynamic shadows artifacts - #71 by Zeblote) and, as far as I can tell, it was never resolved for landscape.
  3. Even with an over-smoothed landscape and high resolution, the issue was still there.
  4. I’m not using Lumen (creates issues with foliage), but it doesn’t fix it anyways.

I’ve attached another screen shot of the issue (in this one the issue is a bit more obvious):

Screenshot 2022-05-12 090322
Screenshot 2022-05-12 0903221638Ă—1054 103 KB

With how old that thread is, I’d be amazed if there isn’t a solution for this issue, especially with the release of UE5.

Again, any help is greatly appreciated!

3

Review the other billion complaints of the same with a forum search. Unless they started deleting posts, which given the situation this forum is in is highly likely.

The only real answer is “use a better engine”.

An alternative answer is, get a 3090 or bettter, disable all shadows and enable only ray traced.

As far as the problem itself goes, it is a combination of low tessellation of the landscape itself - afterall its probably still one vertex per meter - paired to the sorry excuse the engine uses to transition various density components.
Probably also paired to cascade. Which is why going full ray trace helps a little.

In short, unless they actually produce a landscape system that is up to date - complete with fustrum culled vertex streaming instead of chopping components - the issue itself is never going to go away.

Use a mesh instead of the landscape system. Usually its just much better.

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4

“Use a better engine”. Got it. :slight_smile:

Thanks.

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5

I was having a similar issue with a landscape heightmap imported from World Machine. Lightly running the “smooth” sculpt tool over problem areas seemed to help quite a bit. I’m guessing those spots have bad normals or something and just touching them with one of the landscape tools resets them and fixes the problem.

Don’t give up on ol’ UE quite yet! There’s not a better engine out there…

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6

I had the same issue and the solution for me was to disable dynamic shadow-fixed.
Landscape>Lighting>uncheck dynamic shadow

7

Literally any engine you pick has better rendering, including Unity now…

8

That means/assumes you won’t have a day cycle or area lighting that affects shadowing over the landacape, like passing clouds.

Sure, its a solution…

9

Correct. It’s a solution if your project doesn’t require a day/night cycle. In my case it was a cutscene.

10

disable contact shadows in dir light, then play with bias