PCG at runtime crashes when using fast geometry plugin

Development Pipeline & Plugins
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On our project we recently enabled fast geometry and some of our maps we encounter a crash at this location when we use PIE. Worth noting that we have PCG queries running at begin play and ray traces that they are running are hitting the converted fast geometry components.

UnrealEditor-PCG.dll!PCGWorldQueryHelpers::FilterCommonQueryResults(const FPCGWorldCommonQueryParams * QueryParams, const UPrimitiveComponent * TriggeredComponent, const TWeakObjectPtr<UPCGComponent,FWeakObjectPtr> OriginatingComponent, const TSet<TObjectKey<AActor>,DefaultKeyFuncs<TObjectKey<AActor>,0>,FDefaultSetAllocator> & FilteredActorReferences) Line 47

at D:\Repos\Biohazard\Engine\Plugins\PCG\Source\PCG\Private\Helpers\PCGWorldQueryHelpers.cpp(47)

This crash is happening becuase the PCG helper querys is expecting the hitresult to have a hitcomponent when using fast geometry this will not be the case. Does Epic plan to update the PCG plugin to be compatible with Fast geometry? Are there other places in the code base where we could encounter this issue?

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Steps to Reproduce
Take a map with world partition enabled and use the instructions here to enable fast geometry: https://dev.epicgames.com/community/learning/knowledge\-base/r6wl/unreal\-engine\-world\-building\-guide

Now place a static mesh actor in the work and then place a blueprint upon it that will invoke PCG on begin play at the same location and do some ray tracing. The crash will happen 100%.

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Hello [mention removed]​

Thank you for reaching out and bringing this issue to our attention.

I’ve been trying to reproduce the described behavior, but I might be missing some step along the way.

Could you elaborate a bit more on the steps to reproduce, or provide a minimal project that displays this crash?

I hope to hear from you soon.

All the best,

[mention removed]​

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Hey Raf,

I’m afraid my repro is in a map that I can’t share due to confidentiality. Heres a more detailed repro.

Enable fastgeometry in the project and add the fastgeoworldpartitionruntimecelltransformer to the world partition map.

Place a static meshactor with a cube mesh in the map (this should convert to a fastgeometrycomponent in PIE).

Now create a blueprint that has a pcgcomponent. Place an instance of this blueprint actor on top of thestatic mesh actor.

Associate the pgccomponent a PCG graph that will do some ray tracing that will hit the static mesh below it.

Trigger the generate function on the pcg component from the beginplay event

Run the map in PIE it will crash 100%.

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Hello [mention removed]​

Thank you for the added context.

I’ll try it and let you know.

All the best,

[mention removed]​

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Happy to help out if you need more.

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Hello [mention removed]​

I was able to reproduce the described behavior.

I’ve confirmed it is still reproducing on P4 main (UE5.8), so there is no fix in place.

I’ll report this and share the trackable link once I get it.

All the best,

[mention removed]​

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Hello [mention removed]​

Thank you again for reporting this issue.

I’ve made a JIRA report at: Unreal Engine Issues and Bug Tracker (UE\-341082)

Please note that it can take some time to be made publicly accessible.

We don’t provide updates on EPS, but if you would like to track the resolution, check the link for the status.

You also have questions regarding the roadmap and Epic’s plans for solving compatibility issues between PCG and FastGeo.

As a Partner, I don’t have access to this kind of Epic inside information, but I can give an educated guess that they would be very interested in making all these systems compatible.

When asked, Epic typically doesn’t provide dates, as priorities shift constantly.

However, I could escalate the case to Epic, and they can ask internally to try and get you an actual answer.

Let me know how you want to proceed.

All the best,

[mention removed]​