Partitioned PCG Graphs will Duplicate content if utilized in Level Instances

Development Pipeline & Plugins
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Partitioned PCG graphs generate PCGPartitionActors to separate their outputs in a grid. If these graphs are utilized in a level instance, the level instance’s PCGPartitionActors are pulled through and duplicated in the main world. Any changes to a landscape/pcg generating action would cause these LI’ed PCG graphs to run and regenerate content in the main world duplicating content.

This change prevents this duplication and allows LI’ed PCG graphs to generate content based on their location in the parent world. Generated content is also store in the parent world and is not duplicated.

All actions that would cause these partitioned graphs to generate now correct trigger them as well including, moving the LI, changing actor filters, landscape modifications.

Partitioned PCG graphs still work in main worlds regardless of if the main world is used in a level instance somewhere else

Github PR: https://github.com/EpicGames/UnrealEngine/pull/13163

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Steps to Reproduce
Create a PCG Graph

Make the graph spawn objects

Create a Actor with a PCG Component

Set the PCG Component to IsPartitioned

Place the actor in a world and generate the PCG component

Create a new world (World Partitioned)

Add the first world with the PCG actor in as a level instance

The LI’s PCGPartitionActors will be pulled through

Any action that would trigger PCG regeneration (Landscape modifications) will duplicate the content in the main world’s PCGPartitionActor

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Hi Jake,

Thanks for reaching out.

It’s certainly not intended, and I would guess that it has to do with the fact that the components are pre-generated and there’s a state/resource tracking issue.

We will have a look - thanks for the PR link too.

Cheers,

Julien

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Hi Jake,

We are aware that Partitioned graphs inside Level Instance’s are not properly supported. We need to look into it and provide a solution for this.

I am not sure that making the LI’s Partitioned Actors and World Actor main world only will be the solution as that could mean missing data for different setups/graphs.

The tracking of Partitioned Actors should indeed take into account the level in which those Partition Actors live and properly handle readonly level instances.

Cheers,

Patrick

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Thanks for the info! Will keep an eye out for the solution Epic provides when partitioned graphs in level instances become properly supported. If this is not a solution that Epic deems ideal for all graphs/setups then the PR can be closed