Unreal 5.7 RayTracing Crash

Development Rendering
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1

Hi everyone,
I’m running into a consistent crash in Unreal Engine 5.7 and I’m having trouble figuring out the exact cause. I’m hoping someone who has dealt with this before can point me in the right direction.

This is the crash message:

Assertion failed: Scene->RayTracingScene.GetCachedInstanceGeometry(RayTracingInstanceIndexMain) == CachedRayTracingGeometry->GetRHI()
File: PrimitiveSceneInfo.cpp
Line: 395

And before the crash, the log repeatedly shows:

LogRenderer: Using fallback RTPSO
LogPSOHitching: Encountered X PSO creation hitches...

One thing that might be related:
I have foliage meshes (plants) painted with the Foliage tool. These meshes use Nanite, and the material has World Position Offset for wind animation.

My log also shows this warning:

Nanite instanced static mesh using World Position Offset not supported in ray tracing yet

I’m not sure if this warning is directly responsible for the crash, or if it’s just unrelated noise.

I have invisible walls too that might be crashing, but i’m not sure..

Any guidance would be greatly appreciated. I can share full logs, crash context files, and the project setup if needed.

Thanks in advance!

1 Like
2

Hi @Kye1002 !

We are currently investigating this crash. Are you able to reproduce it in a small project that you could share with us?

Thanks!

3

Hello Tiago!

Unfortunately I can’t share the full project because it’s under an NDA, but I can gather any specific logs or files you might need. The crash is a bit inconsistent on my side, so I’m not fully sure what’s triggering it yet.

If there’s any particular log, trace, or setting you want me to extract, just let me know and I’ll send it over.

4

Ah ok.

Do you know if there’s any logic in the project (such as blueprints) that calls SetEvaluateWorldPositionOffsetInRayTracingto toggle whether WPO is enabled on static mesh components?

5

Hello!

There’s no blueprint with that logic on the project, and i used the command r.RayTracing.Geometry.StaticMeshes.WPO=0 and unreal still crashed, we tested on 5.7.0 and 5.7.1.

2 Likes
7

Any progress on this issue? I am having this crashing too. Please help!

8

Hi Tiago, do you have any suggestion on this? We’re having too many crashes with different maps and projects on this error.

Is there any fix comming?

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Yeah this is an issue here too, def. an issue in relation to scenes with transparency or foligage in 5.7.1

10

Is your outside directional light set to raytracing? You should use VSM for nanite, just check the light setting and mega lights setting if you use it.

11

Unfortunately I haven’t been able to reproduce this crash myself yet so I haven’t been able to track down and fix the root cause. 5.7.2 includes changes to output more extensive logging when this happens so hopefully I’ll get more data that way.

@LeonZJU @duncancatterall1 are you able to share a project where you hit this with us for further investigation?

12

@LeonZJU @duncancatterall1 I think we have identified the issue and submitted a fix https://github.com/EpicGames/UnrealEngine/commit/cd9e295a4808b130e7b9781a32df0da1dfe2d3dd.

This should be included in an upcoming hotfix to UE 5.7.

In the meantime if you are able to manually integrate the change above and test it let me know.