Landscape Patches casues PCGWorldPartitionBuilder commandlet to crash when merging weightmaps(new batch merge)

Development World Creation
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1

I’ve added the callstack from our internal project since it has the debug symbols but it is the exact same crash as in the vanilla sample project that I have attached, which does not have symbols and since it crashes in the command line via the commandlet it does not throw up the crash reporter.

Generally the repo requirements are:

  • Landscape in a map with World Partition
  • Using Landscape Patches with weightmaps
  • using the cvar landscape.EditLayersLocalMerge.Enabled=2
  • PCG HiGen content that can be built through the PCGWorldPartitionBuilder commandlet
    • Currently spawning patches, but have been able to repo without spawning patches specifically
2

Steps to Reproduce

Hello!

In our project we are using the Landscape Patches plugin, along with PCG and World Partition to create a large procedural map.

When using the PCGWorldPartitionBuilder along side landscape patches utilizing the new Batch Merge option(landscape.EditLayersLocalMerge.Enabled=2) there is a crash when building. It seems to only happen via the commandlet as loading up the whole map in the editor and building landscape/PCG manually doesn’t crash, nor throw any errors, so this only seems to stem for the commandlet.

The main cause of the crash seems to stem from ALandscape::PerformLayersWeightmapsBatchedMerge function which is failing due to a null external texture.

I’ve attached a vanilla repo project, which contains a large static landscape patch, and a PCG graph spawning more patches but the crash has been triggered before without the PCG graph spawning patches as well, but being able to spawn patches with PCG would be ideal, if this is not a supported workflow it would also be great to know as it does indeed seem to work fine if done manually within the editor without the commandlet.

Let me know if anymore information is needed :slight_smile:

Cheers,

Andre

3

Hi,

I apologize for the delay. Thanks for providing the repro, which also crashed for me. I’m taking a look into it and will report back and update before the end of the week.

Thanks,

Ryan

4

I found that the crash is no longer happening in UE5-Main, although I’m unsure of the change that is responsible for fixing it. Is the other workflow of not going through the commandlet a sufficient workaround for you currently? If not, I can dig around to see if I can find the change, and hopefully it will be trivial to backport if so.

-Ryan

5

Hi Ryan,

Just chiming in here that the commandlet would be very beneficial for us. So if you could find the CL that fixed it, maybe we can take that and integrate into our build.

Cheers

//

Martin

6

Sorry, haven’t had much time to hunt this down yet. Could you check if LocalMerge (i.e., landscape.EditLayersLocalMerge.Enabled=1) works? From what I understand, it should be more or less the same benefits, except BatchMerge is backwards compatible with all landscapes, including those using Landscape BP brushes (using Landscape BP brushes still results in similar behavior as global merge, though).

-Ryan

7

Hi Ryan,

Thanks for diving into this deeper, and good to know something has fixed it going forwards :smiley:

Unfortunately we would like to rely heavily on the PCG commandlet due to memory requirements for our larger world map, to save us time manually re-generating all the local maps and we are using world partition with PCG set to Load as Preview so many artists/designers can work on a singular map file, see the results and not have to worry about conflicts in P4.

I’m not sure we can work without the commandlet but if there are some tricks we can do in the meantime to make updating PCG across many map files easier, or to lower the memory needed to generate a large amounts of PCG content then we could possible hold out for an update if a backport is not realistic.