Linker error FMeshDescription

Development Programming & Scripting
1

Sorry, title edit. I was reading a few things that got StaticMeshDescription stuck in my head. I don’t actually use a StaticMeshDescription object anywhere. Just a FMeshDescription object that is instantiated as “FMeshDescription MeshDescription = BuildMeshDescription(AssetNode.ProcMeshComponent);”

2

TITLE EDIT: StaticMeshDescription to FMeshDescription

Hi,
A fairly simple issue that I’m unable to fix…

I am trying to convert procedural meshes to static meshes in c++. To do this I lifted the code present in ProceduralMeshComponentDetails.cpp and added it to my main code. When I compile, I get linker errors with FMeshDescription-

LNK2019 unresolved external symbol “__declspec(dllimport) public: __cdecl FMeshDescription::~FMeshDescription(void)” (_imp??1FMeshDescription@@QEAA@XZ) referenced in function “public: void __cdecl ARealtimeCADModelActor::DrawPrim(struct FMeshSection)” (?DrawPrim@ARealtimeCADModelActor@@QEAAXUFMeshSection@@@Z)
LNK2019 unresolved external symbol “__declspec(dllimport) public: __cdecl FMeshDescription::FMeshDescription(struct FMeshDescription &&)” (_imp??0FMeshDescription@@QEAA@$$QEAU0@@Z) referenced in function “public: void __cdecl ARealtimeCADModelActor::DrawPrim(struct FMeshSection)” (?DrawPrim@ARealtimeCADModelActor@@QEAAXUFMeshSection@@@Z)
LNK2001 unresolved external symbol “public: __cdecl FMeshDescription::~FMeshDescription(void)” (??1FMeshDescription@@QEAA@XZ)

I looked up a couple of similar posts and it appears that the issue seems to be in the build script where I need to add dependencies. So, I added the MeshDescription module to my publicdependency string in the build script as follows but the issue still persists.

PublicDependencyModuleNames.AddRange(new string[] { “Core”, “CoreUObject”, “Engine”, “AssetRegistry”, “MeshDescription”, “InputCore”, “ProceduralMeshComponent”, });

What should I be doing here?

3

I see there is a method "ARealtimeCadModelActor::DrawPrim(struct FMeshSection)

FMeshSection is part of AlembicLibrary module, maybe that could solve the issue?

4

Sadly no:/

FMeshDescription is defined in MeshDescription.h. I have two git-built versions of unreal, 4.22 and 4.25. Intellisense shows two both versions of the header. Is it possible that my project is referencing the wrong version?

5

I’m talking about FMeshSection, not FMeshDescription.

6

Ah ok! Sorry! It got me a bit confused.

7

The FMeshSection that I’m using is a custom defined struct that is not related to the AlembicLibrary module. I’ve not included that module and hence there should be no conflicts there

8

You should add the “StaticMeshDescription” module to your build.cs file.

9

Correct module name is “MeshDescription”.
How to figure it out

  1. Open Visual Studio, open the file, referencing undefined symbol
  2. Ctrl-Left Mouse Click on it, and Visual studio shows you list of sources, where it is declared.
    In my case it was C:\Program Files\Epic Games\UE_4.26\Engine\Source\Runtime\MeshDescription\Public\MeshDescription.h
  3. Looking for .build.cs file near that header, I’ve found that it is MeshDescription.build.cs