UE crashes Heterogeneous volume

HI UE community,

I am stuck with a bug that never occured before, but now suddenly it does. When I try to assign a volume material to a Heterogenous volume, my game just crashes, however this setting is enabled in my engine settings. I use UE5.5 from the Epic Launcher.

I also tried creating an empty volume material but even that one crashes my editor.

LoginId:b63a56c54a83cfdbc5770f926fabda8f
EpicAccountId:261562a4ec114b50bd34d063d0ca6e51

Fatal error: [File:D:\build\++UE5\Sync\Engine\Source\Runtime\RenderCore\Private\ShaderParameterStruct.cpp] [Line: 473] 
FRenderSingleScatteringWithLiveShadingDirectCS's required shader parameter FParameters::RWHoldoutTexture was not set.


UnrealEditor_RenderCore
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kernel32
ntdll


Any help is greatly appreciated!

Tristan

Hey there @TristanPiejn! Particle volumes are always a bit finicky depending on your graphical environment. Sometimes they work amazingly, and other times they fail or have rendering issues. In this case however the full crash is a bit of an issue.

This seems to be an issue with the way scattering and shadows are being processed.

Are you using hardware raytracing? If so, does disabling it change anything?

Hi :slight_smile:

First of all, thank you so much for your interest I really appreciate it alot!
I have these settings and still not working :confused:

Do you maybe have some other suggestions?

Hmm, alright. Let’s try some CVars that could help sidestep the rendering issue. I still believe it to be related to the shadow handling, but it could be cascading from another portion. These CVars will possibly break functionality in some areas, but if they avoid the crash it will give us some solid information.

r.HeterogeneousVolumes.DepthSort 0
This disables transparency depth sorting. Probably messes up the look of the effect, but if the sorting is causing this, this action will show us.

r.HeterogeneousVolumes.IndirectLighting 0
Disables indirect lighting altogether for the volumes.

r.PathTracing.HeterogeneousVolumes.RebuildEveryFrame false
This is only for making sure the engine can’t check for the path tracing side at all, even if it’s not being used.

Hi again, thanks for being so helpful!

image
I tried your CVARs but still it’s crahsing. I also tried in a different UE project and the Heterogenous volume works there with the exact same engine version 5.5. But even if i take the exact same rendering setting from another project settings, my editor for the project I actually need the VDBs for will still crash. And I am using the sparevolume material form the engine content so I don’t think it’s the material but rather maybe something else..?

Further help much appreicated

Here a proof that this works in an empty project

Since it’s working for other projects, there’s got to be either a setting or a caching issue.

Settings wise you can verify they are the same with the fresh projects, so I’ll focus on the caches.

First back your project up somewhere. Source control is best, but a copy will do if you don’t have any source control setup.

After backing up your project, delete these folders while the project is closed, and they’ll regenerate when you launch the project. This will rebuild a ton of cached data so it may take a bit.

  • Saved
  • Intermediate
  • DerivedDataCache

Then try again.

Thanks a lot for the suggestion! I tried deleting these but still it will crash…
We work with source control, but we’re really clueless because it persists across the entire team. Do you think maybe this is some type of issue related to the project settings?
Once again I really appreciate all your time you put into it to help look into this issue.
I have try browsing again for this crash message but I still can’t find anything about it sadly.

I’ve never seen this specific issue, was just judging from the error message. I’ll have to check out the source when I get into office later and see if I can follow the chain. It might provide a bit more insight.

We reworked our DefaultEngine.ini file.

This is what fixed it for us: r.Deferred.SupportPrimitiveAlphaHoldout=False

I have clue why it was even causing these problems but I hope it can help other people in the future.