I also have the same problem. Has anyone created a Bug report on the UE bug tracker? If so, can you share the link so we can see their decision about it? Thanks!
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We are having the samme issue
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Updated to UE 5.6.1 and the bug is still present.
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Hey @Dazzling_Divine 
Thanks for highlighting this issue. I’ve gone ahead and created a public bug that you can track here: Unreal Engine Issues and Bug Tracker (UE-314241).
It does look like a valid bug but I do have some follow up questions around your scene if you don’t mind providing me some information!
- In your scene, does your lighting ray traced shadows enabled?
- Can your confirm any project settings you may have modified?
Thanks!
Ahh my apologies, I misspoke. The Foliage tool generates Instance Static Meshes (ISMs) when painting. ISMs with WPO enable are not supported in Ray Tracing at this time. We actually only added Nanite/SM with WPO enabled to Ray Tracing as of Release-5.6.
Let me breakdown the current support:
| Mesh Type | Nanite | WPO Enabled | Ray Tracing (RT) Support |
|---|---|---|---|
| SM/ISM |  |
 |
|
| SM/ISM | |
|
|
| SM | |
|
|
| ISM | |
|
|
*Key
- SM = Static Mesh
- ISM = Instance Static Mesh
Hope this clarifies!
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Hi Matthew,
Thanks for the response and for creating the public bug report!
To answer your questions:
-
I don’t have Ray Traced Shadows enabled in my project.
-
I’m using Lumen with Virtual Shadow Maps, but the issue still persists even if I turn Lumen off.
-
I also tested this in a completely new project with default settings (no modifications), and the issue still occurs.
Let me know if you’d like me to share any additional project files or screenshots to help with reproducing the bug.
Thanks for the detailed breakdown, that helps a lot. Just to clarify, in 5.5 this worked as expected but in 5.6 it no longer does. Was support for Nanite ISMs with WPO and shadows removed in 5.6, or is this an unintended regression?
Also, do you plan to reintroduce this support in a future 5.6 update? It’s a deal breaker for my project if not, and I may have to stick with 5.5.
One more point, in your table you mention “Ray Tracing (RT) Support”. Could you clarify if you mean Hardware Lumen when you say RT Support, or traditional hardware ray tracing?
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Was support for Nanite ISMs with WPO and shadows removed in 5.6, or is this an unintended regression?Also, do you plan to reintroduce this support in a future 5.6 update? It’s a deal breaker for my project if not, and I may have to stick with 5.5.
Nothing was removed, we have not supported Nanite + ISM + WPO; it does not have ray tracing representation and therefore would not display in any effects using hardware ray tracing (both Lumen and traditional Ray Tracing). We only added support for Nanite + SM + WPO in RT as of 5.6.
One more point, in your table you mention “Ray Tracing (RT) Support”. Could you clarify if you mean Hardware Lumen when you say RT Support, or traditional hardware ray tracing?
Ray Tracing (RT) Support would mean that there is no representation in the Ray Tracing scene which means it will not display in any effects utilizing hardware ray tracing (Lumen HWRT, Path Tracing (PT), Ray Tracing Shadows (RTS), Niagara HWRT collisions, etc.)
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I think this is a different issue. In Unreal Engine 5.5, Nanite + WPO foliage painted with the Foliage Tool casts shadows correctly, with or without Hardware Lumen. In 5.6, however, shadows are missing entirely whenever WPO is enabled, regardless of whether Lumen or Ray Tracing is used. So it seems unrelated to Lumen or RT and is specifically a WPO shadow issue introduced in 5.6.
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I think this is a different issue. In Unreal Engine 5.5, Nanite + WPO foliage painted with the Foliage Tool casts shadows correctly, with or without Hardware Lumen. In 5.6, however, shadows are missing entirely whenever WPO is enabled, regardless of whether Lumen or Ray Tracing is used. So it seems unrelated to Lumen or RT and is specifically a WPO shadow issue introduced in 5.6.
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What are you talking about? Nanite + ISM (foliage tool) + WPO works perfectly fine in 5.5! 5.6 clearly broke something. It’s a known bug since the launch of 5.6 and still hasn’t been fixed in 5.6.1, which makes Nanite unusable if you’re using any kind of animated foliage. As Dazzling_Divine said, it seems unrelated to Lumen or RT and more a WPO shadow issue.
A quick look at the forum shows that a bunch of common issues still haven’t been addressed in 5.6.1 — it’s really not very professional.
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Awesome update, my scene works fine in 5.5.4 but in 5.6.1 i see this. I know a lot of console command tweaks and all of them are helpless. This is crazy how they can destroy basic functions with their updates. There is no WPO, there is just foliage with nanite trees
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just to add on, the shadow work in packaged build 5.5.4 works, but not 5.6 so something broke.
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I can confirm this happens to me too. It worked fine on 5.5
Whenever you have nanite trees painted with the foliage tool, if you enable “Evaluate World Position Offset” for the painted Foliage Types, they will not be represented anymore in the Lumen Scene thus loosing Indirect Lighting occlusion completely.
This is a very important issue, by the way.
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You may need wind effects on those trees but, as for now, I suggest you disable “Evaluate World Position Offset” in the settings of the Foliage Types, and you will have the trees back in the Lumen Scene and therefore you´ll get proper occlusion from them.
Hi guys, got the same problem on same engine version on nanite + WPO + Instanced foliage actor
For me, the solution was to untick this box on the instanced foliage actor and everything started to work properly.
Hope this helps !
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Hi Matthew,
I am having the same issue as @Dazzling_Divine and @Frakatchoo. This doesn’t look to be by design and is a glitch. If it is by design then it is incredibly confusing the change.
I have tested the exact setup on UE5.5 and UE5.6. UE5.5 the shading is the same between the foliage instance and static mesh actor.
Luckily @Narom42 solution did fix it!
When unchecking Evaluate World Position Offset in Ray Tracing in the Instanced Component in UE5.6 this fixes the issue. When unchecking Evaluate World Position Offset in Ray Tracing in UE5.5 there is no change (but it doesn’t matter because as everyone is saying there is no issue in UE5.5).
It is either there is a bug in UE5.6 or in UE5.5. Can the team please clarify what changed between the two?
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Ah, I see exactly what’s happening — this is a known limitation in Unreal Engine (including 5.6):
When you use World Position Offset (WPO) in a material, Nanite meshes no longer cast dynamic shadows from the offset geometry. Nanite evaluates shadows from the base mesh only, and currently doesn’t account for vertex displacement applied in the material. That’s why your foliage painted with the Foliage Tool looks correct visually, but shadows disappear or stay “stuck” to the original mesh position once WPO is enabled.
I think I’ve found a solution… I was struggling with this at first since I didn’t want to give up my ray tracing shadows just to get Nanite shadows to show up. But here’s what worked for me: go to your foliage section, select your foliage in the brushes, and disable “Evaluate World Position Offset.” As soon as I did that, the shadows came back. Hope this helps! (pic in link)UE5 Reference Pic
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