Crash when exporting a tree with custom Nanite Assemblies in Procedural Vegetation Editor (UE 5.8)
Description
I created a custom Nanite Assembly from a combination of static meshes using Scripted Actor Actions > Nanite Assemblies > CreateNewStaticMeshAssemblyFromSelection. The generated assembly works and renders correctly within the Procedural Vegetation Editor (PVE). However, attempting to export the tree causes Unreal Engine to crash.
Crash Code
Fatal error: [File:D:\build\++UE5\Sync\Engine\Source\Runtime\Core\Private\Containers\ContainerHelpers.cpp] [Line: 8]
Trying to resize TArray to an invalid size of 18446744073709551615
UnrealEditor_Core
UnrealEditor_DynamicMesh
UnrealEditor_DynamicMesh
UnrealEditor_DynamicMesh
UnrealEditor_ModelingOperators
UnrealEditor_GeometryScriptingCore
UnrealEditor_GeometryFramework
UnrealEditor_GeometryFramework
UnrealEditor_GeometryScriptingCore
UnrealEditor_ProceduralVegetationEditor
UnrealEditor_ProceduralVegetationEditor
UnrealEditor_ProceduralVegetationEditor
UnrealEditor_ProceduralVegetationEditor
UnrealEditor_ProceduralVegetationEditor
UnrealEditor_ProceduralVegetationEditor
UnrealEditor_ProceduralVegetationEditor
UnrealEditor_Slate
UnrealEditor_Slate
UnrealEditor_Slate
UnrealEditor_Slate
UnrealEditor_Slate
UnrealEditor_Slate
UnrealEditor_Slate
UnrealEditor_ApplicationCore
UnrealEditor_ApplicationCore
UnrealEditor_ApplicationCore
UnrealEditor_ApplicationCore
user32
user32
UnrealEditor_ApplicationCore
UnrealEditor
UnrealEditor
UnrealEditor
UnrealEditor
UnrealEditor
UnrealEditor
kernel32
ntdll
Steps to Reproduce:
- Drop all assets required for the Nanite Assembly into the level (For Nanite Assemble I use Nanite meshes)
- Run the Editor Utility Action:
'CreateNewStaticMeshAssemblyFromSelection'
- Open the Procedural Vegetation Editor, create a new Foliage Palette, and add the newly created Nanite Assembly to it. (In my case “PVE_Sample_Conifer_Tree_01” asset)
- Export the asset as a Skeletal Mesh with voxelized Nanite
- Crash
**
Exporting as a Static Mesh**: If exported as a Static Mesh instead, Unreal Engine does not crash, but the instances within the exported tree become invisible.
I tried different meshes with different settings. In this article, it’s just a group of nanite spheres created in Unreal.
The only current solution is merging the meshes into a standard Static Mesh. While this avoids the crash, it completely nullifies the benefit of creating a Nanite Assembly.