Crash of the engine when trying to convert models to Nanite

Development Rendering
,
1

When trying to translate my old meshes, I got an engine crash. Simpler meshes were able to be translated, but more detailed ones caused a crash.
I found out that this only happens with models exported via datasmith.
In the 3d editor (c4d), I converted the model to FBX and after importing successfully converted it to nanite.
// i used datasmith c4d

2

I had the same problem. I found that if I converted the mesh to a static mesh in UE (right click on mesh and select ‘Convert StaticMesh’) and then converted it to Nanite, the conversion worked fine.

1 Like
3

Still with the new UE5 version converting static meshes to nanite crashes sometimes, depending on the mesh, not sure what it causes, but I know that the conversion to nanite worked with these meshes in the EA version. Here is the crash report:

image
image812×170 6.84 KB

4

I also experience crashes sometimes. I found a way out only by changing the grid in advance in a 3d editor (retopology)
But I didn’t find any dependencies.

5

I think I will try dynamesh with zbursh and baking the textures on the new mesh… very complicated. I don’t understand why it works in the early access better than in the release version. This is not production ready, in my opinion.

1 Like
6

I have a city of the high-quality buildings containing more than 5000 static meshes when I try to convert it to nanite it crashes every single time.

1 Like
7

I found the mesh that was causing the crashes it’s a simple mesh with the 750 polycounts. I am still confused why is it causing the problem

1 Like
8

Hi, I’ve searched for a while now, and your the only one I’ve found with the same crash.
Have you been able to fix the issue?

9

I think there is some mesh that has problems (like maybe wrong geometry). so try to convert one by one and leave the one that is causing the crashes

1 Like
10

This is the exact same issue I have. Somehow this is the only other thread I’ve found where people discuss the issue.

For me, this issue only occurs on some OBJ meshes, the common thread being that they are exported from a program called Mineways. Furthermore, only some meshes exported by this program cause this issue.

Here is an example of a mesh that is causing the crash.
Content.7z (2.1 MB)

Crash log example 
LoginId:545888a54c5b318d49af42a165f56347
EpicAccountId:62a8b1e81bfe4db79ace3ff2aaadb4a9

Assertion failed: Simplifier.GetRemainingNumVerts() > 0 [File:D:\build\++UE5\Sync\Engine\Source\Developer\NaniteBuilder\Private\Cluster.cpp] [Line: 414]

UnrealEditor_NaniteBuilder!Nanite::FCluster::Simplify() [D:\build\++UE5\Sync\Engine\Source\Developer\NaniteBuilder\Private\Cluster.cpp:414]
UnrealEditor_NaniteBuilder!Nanite::DAGReduce() [D:\build\++UE5\Sync\Engine\Source\Developer\NaniteBuilder\Private\ClusterDAG.cpp:354]
UnrealEditor_NaniteBuilder!Nanite::BuildDAG() [D:\build\++UE5\Sync\Engine\Source\Developer\NaniteBuilder\Private\ClusterDAG.cpp:72]
UnrealEditor_NaniteBuilder!Nanite::BuildNaniteData() [D:\build\++UE5\Sync\Engine\Source\Developer\NaniteBuilder\Private\NaniteBuilder.cpp:579]
UnrealEditor_NaniteBuilder!Nanite::FBuilderModule::Build() [D:\build\++UE5\Sync\Engine\Source\Developer\NaniteBuilder\Private\NaniteBuilder.cpp:805]
UnrealEditor_MeshBuilder!BuildNanite() [D:\build\++UE5\Sync\Engine\Source\Developer\MeshBuilder\Private\StaticMeshBuilder.cpp:205]
UnrealEditor_MeshBuilder!FStaticMeshBuilder::Build() [D:\build\++UE5\Sync\Engine\Source\Developer\MeshBuilder\Private\StaticMeshBuilder.cpp:372]
UnrealEditor_MeshBuilder!FMeshBuilderModule::BuildMesh() [D:\build\++UE5\Sync\Engine\Source\Developer\MeshBuilder\Private\MeshBuilderModule.cpp:50]
UnrealEditor_Engine!FStaticMeshRenderData::Cache() [D:\build\++UE5\Sync\Engine\Source\Runtime\Engine\Private\StaticMesh.cpp:2970]
UnrealEditor_Engine!UStaticMesh::CacheDerivedData() [D:\build\++UE5\Sync\Engine\Source\Runtime\Engine\Private\StaticMesh.cpp:5199]
UnrealEditor_Engine!UStaticMesh::ExecuteBuildInternal() [D:\build\++UE5\Sync\Engine\Source\Runtime\Engine\Private\StaticMeshBuild.cpp:455]
UnrealEditor_Engine!FAsyncTask<FStaticMeshAsyncBuildWorker>::DoTaskWork() [D:\build\++UE5\Sync\Engine\Source\Runtime\Core\Public\Async\AsyncWork.h:636]
UnrealEditor_Engine!FAsyncTaskBase::DoWork() [D:\build\++UE5\Sync\Engine\Source\Runtime\Core\Public\Async\AsyncWork.h:304]
UnrealEditor_Engine!FAsyncTaskBase::DoThreadedWork() [D:\build\++UE5\Sync\Engine\Source\Runtime\Core\Public\Async\AsyncWork.h:328]
UnrealEditor_Core!FQueuedThreadPoolWrapper::FScheduledWork::DoThreadedWork() [D:\build\++UE5\Sync\Engine\Source\Runtime\Core\Public\Misc\QueuedThreadPoolWrapper.h:128]
UnrealEditor_Core!FQueuedThreadPoolWrapper::FScheduledWork::DoThreadedWork() [D:\build\++UE5\Sync\Engine\Source\Runtime\Core\Public\Misc\QueuedThreadPoolWrapper.h:128]
UnrealEditor_Core!<lambda_2cfb882046ba83e24f4606b279dfb220>::operator()() [D:\build\++UE5\Sync\Engine\Source\Runtime\Core\Public\Async\Fundamental\Task.h:504]
UnrealEditor_Core!LowLevelTasks::TTaskDelegate<LowLevelTasks::FTask * __cdecl(bool),48>::TTaskDelegateImpl<<lambda_2cfb882046ba83e24f4606b279dfb220>,0>::CallAndMove() [D:\build\++UE5\Sync\Engine\Source\Runtime\Core\Public\Async\Fundamental\TaskDelegate.h:171]
UnrealEditor_Core!LowLevelTasks::FTask::ExecuteTask() [D:\build\++UE5\Sync\Engine\Source\Runtime\Core\Public\Async\Fundamental\Task.h:656]
UnrealEditor_Core!LowLevelTasks::FScheduler::ExecuteTask() [D:\build\++UE5\Sync\Engine\Source\Runtime\Core\Private\Async\Fundamental\Scheduler.cpp:184]
UnrealEditor_Core!LowLevelTasks::FScheduler::TryExecuteTaskFrom<&LowLevelTasks::TLocalQueueRegistry<1024>::TLocalQueue::DequeueGlobal,0>() [D:\build\++UE5\Sync\Engine\Source\Runtime\Core\Private\Async\Fundamental\Scheduler.cpp:361]
UnrealEditor_Core!LowLevelTasks::FScheduler::WorkerMain() [D:\build\++UE5\Sync\Engine\Source\Runtime\Core\Private\Async\Fundamental\Scheduler.cpp:402]
UnrealEditor_Core!UE::Core::Private::Function::TFunctionRefCaller<<lambda_0a548c7e497de3cc77a9e48080e1524f>,void __cdecl(void)>::Call() [D:\build\++UE5\Sync\Engine\Source\Runtime\Core\Public\Templates\Function.h:475]
UnrealEditor_Core!FThreadImpl::Run() [D:\build\++UE5\Sync\Engine\Source\Runtime\Core\Private\HAL\Thread.cpp:67]
UnrealEditor_Core!FRunnableThreadWin::Run() [D:\build\++UE5\Sync\Engine\Source\Runtime\Core\Private\Windows\WindowsRunnableThread.cpp:149]

I have no clue what is causing the issue, but I would gladly have it resolved as Nanite is essential to many of my workflows.

11

I’ve had similar issues. Try this;

Export the mesh as an FBX then import back to your uproject (all using default settings) then run the nanite conversion.

2 Likes
12

Please check again if your mesh has more than 64 material slots. Nanite only works with mesh below 64 material slots.

1 Like
13

hey, has anyone found a solution to this? Im in 5.2, batch importing a lot of FBX files and some of them fail (with the same error) if Nanite is enabled

14

I have since found enabling “preserve area” in the meshs’ nanite settings prevents the crash in 5.2

1 Like
15

I spoke too soon, the crash does still occasionally occur on some meshes

16

That worked for me, about a max of 63 material IDS thanks!

17

Also getting crashes, but I think it could be because Nanite doesn’t work on translucent materials