bCombineMeshes
bCombineMeshes
#Overview
name: bCombineMeshes
The value of this variable can be defined or overridden in .ini config files. 1 .ini config file referencing this setting variable.
It is referenced in 16 C++ source files.
#Summary
#Usage in the C++ source code
The purpose of bCombineMeshes is to control whether multiple static meshes in an FBX file should be combined into a single monolithic mesh when importing into Unreal Engine.
This setting variable is primarily used in the Unreal Engine’s FBX import system, specifically for static mesh imports. It’s part of the UFbxStaticMeshImportData class, which is used to configure various aspects of static mesh imports from FBX files.
The Unreal Engine subsystems that rely on this variable include:
- The FBX import system in the UnrealEd module
- The Interchange Editor plugin, which is a newer asset import framework
The value of this variable is typically set in the FBX import UI or through import settings. It can be modified programmatically or through the editor interface when importing FBX files.
This variable interacts with other import settings, particularly:
- bImportStaticMeshLODs: When both are true, it can trigger special behavior for LOD groups.
- Other mesh import options like bGenerateLightmapUVs, bRemoveDegenerates, etc.
Developers should be aware that:
- When true, it combines all meshes in the FBX into a single static mesh.
- It may be overridden if LOD groups are detected in the FBX file.
- It affects how the import process handles multiple meshes and LOD groups.
Best practices when using this variable:
- Use it when you want to consolidate multiple mesh parts into a single static mesh asset.
- Be cautious when using it with files that contain LOD groups, as it may lead to unexpected results.
- Consider the performance implications of combining many meshes versus keeping them separate.
- Always test the result after import to ensure the combined mesh meets your requirements.
#Setting Variables
#References In INI files
Location: <Workspace>/Engine/Config/BaseEditorPerProjectUserSettings.ini:663, section: [/Script/UnrealEd.FbxStaticMeshImportData]
- INI Section:
/Script/UnrealEd.FbxStaticMeshImportData - Raw value:
False - Is Array:
False
#References in C++ code
#Callsites
This variable is referenced in the following C++ source code:
#Loc: <Workspace>/Engine/Plugins/Interchange/Editor/Source/InterchangeEditor/Private/InterchangeFbxAssetImportDataConverter.cpp:151
Scope (from outer to inner):
file
namespace UE::Interchange::Private
function void FillInterchangeGenericAssetsPipelineFromFbxStaticMeshImportData
Source code excerpt:
GenericAssetPipeline->MeshPipeline->bBuildNanite = StaticMeshImportData->bBuildNanite;
GenericAssetPipeline->MeshPipeline->bBuildReversedIndexBuffer = StaticMeshImportData->bBuildReversedIndexBuffer;
GenericAssetPipeline->MeshPipeline->bCombineStaticMeshes = StaticMeshImportData->bCombineMeshes;
GenericAssetPipeline->MeshPipeline->bGenerateLightmapUVs = StaticMeshImportData->bGenerateLightmapUVs;
GenericAssetPipeline->MeshPipeline->bOneConvexHullPerUCX = StaticMeshImportData->bOneConvexHullPerUCX;
GenericAssetPipeline->CommonMeshesProperties->bRemoveDegenerates = StaticMeshImportData->bRemoveDegenerates;
GenericAssetPipeline->MeshPipeline->DistanceFieldResolutionScale = StaticMeshImportData->DistanceFieldResolutionScale;
GenericAssetPipeline->MeshPipeline->LodGroup = StaticMeshImportData->StaticMeshLODGroup;
if (StaticMeshImportData->VertexColorImportOption == EVertexColorImportOption::Ignore)
#Loc: <Workspace>/Engine/Plugins/Interchange/Editor/Source/InterchangeEditor/Private/InterchangeFbxAssetImportDataConverter.cpp:316
Scope (from outer to inner):
file
namespace UE::Interchange::Private
function UAssetImportData* ConvertToLegacyFbx
Source code excerpt:
DestinationStaticMeshImportData->bBuildNanite = GenericAssetPipeline->MeshPipeline->bBuildNanite;
DestinationStaticMeshImportData->bBuildReversedIndexBuffer = GenericAssetPipeline->MeshPipeline->bBuildReversedIndexBuffer;
DestinationStaticMeshImportData->bCombineMeshes = GenericAssetPipeline->MeshPipeline->bCombineStaticMeshes;
DestinationStaticMeshImportData->bGenerateLightmapUVs = GenericAssetPipeline->MeshPipeline->bGenerateLightmapUVs;
DestinationStaticMeshImportData->bOneConvexHullPerUCX = GenericAssetPipeline->MeshPipeline->bOneConvexHullPerUCX;
DestinationStaticMeshImportData->bRemoveDegenerates = GenericAssetPipeline->CommonMeshesProperties->bRemoveDegenerates;
DestinationStaticMeshImportData->DistanceFieldResolutionScale = GenericAssetPipeline->MeshPipeline->DistanceFieldResolutionScale;
DestinationStaticMeshImportData->StaticMeshLODGroup = GenericAssetPipeline->MeshPipeline->LodGroup;
if (GenericAssetPipeline->CommonMeshesProperties->VertexColorImportOption == EInterchangeVertexColorImportOption::IVCIO_Ignore)
#Loc: <Workspace>/Engine/Source/Editor/DetailCustomizations/Private/FbxImportUIDetails.cpp:291
Scope (from outer to inner):
file
function void FFbxImportUIDetails::CustomizeDetails
lambda-function
Source code excerpt:
Property->GetFName() == GET_MEMBER_NAME_CHECKED(UFbxImportUI, bImportRigidMesh) ||
Property->GetFName() == GET_MEMBER_NAME_CHECKED(UFbxSkeletalMeshImportData, bImportMeshesInBoneHierarchy) ||
Property->GetFName() == GET_MEMBER_NAME_CHECKED(UFbxStaticMeshImportData, bCombineMeshes)
)
{
AddRefreshCustomDetailEvent(Handle);
}
}
};
#Loc: <Workspace>/Engine/Source/Editor/UnrealEd/Classes/Factories/FbxStaticMeshImportData.h:54
Scope (from outer to inner):
file
class class UFbxStaticMeshImportData : public UFbxMeshImportData
Source code excerpt:
/** For static meshes, enabling this option will combine all meshes in the FBX into a single monolithic mesh in Unreal */
UPROPERTY(EditAnywhere, BlueprintReadWrite, AdvancedDisplay, config, Category = Mesh, meta = (ToolTip = "If enabled, combines all meshes into a single mesh", ImportType = "StaticMesh"))
uint32 bCombineMeshes : 1;
/**
* Scale to apply to the mesh when allocating the distance field volume texture.
* The default scale is 1, which is assuming that the mesh will be placed unscaled in the world.
*/
UPROPERTY(EditAnywhere, BlueprintReadWrite, AdvancedDisplay, config, Category= Mesh, meta=(ImportType="StaticMesh"))
#Loc: <Workspace>/Engine/Source/Editor/UnrealEd/Private/Factories/EditorFactories.cpp:6112
Scope (from outer to inner):
file
function EReimportResult::Type UReimportFbxStaticMeshFactory::Reimport
Source code excerpt:
ReimportUI->MeshTypeToImport = FBXIT_StaticMesh;
ReimportUI->StaticMeshImportData->bCombineMeshes = true;
if (!ImportUI)
{
ImportUI = NewObject<UFbxImportUI>(this, NAME_None, RF_Public);
}
//Prevent any UI for automation, unattended and commandlet
#Loc: <Workspace>/Engine/Source/Editor/UnrealEd/Private/Fbx/FbxFactory.cpp:432
Scope (from outer to inner):
file
function UObject* UFbxFactory::FactoryCreateFile
Source code excerpt:
bool bImportStaticMeshLODs = ImportUI->StaticMeshImportData->bImportMeshLODs;
bool bCombineMeshes = ImportUI->StaticMeshImportData->bCombineMeshes;
bool bCombineMeshesLOD = false;
const bool bCanImportStaticMesh = FbxImporter->CanImportClass(UStaticMesh::StaticClass());
//We can import skeletal mesh only if we can import skeleton or a skeleton was specified in the import options
const bool bCanImportSkeletalMesh = FbxImporter->CanImportClass(USkeletalMesh::StaticClass()) && (ImportOptions->SkeletonForAnimation || FbxImporter->CanImportClass(USkeleton::StaticClass()));
const bool bCanImportAnimSequence = FbxImporter->CanImportClass(UAnimSequence::StaticClass());
#Loc: <Workspace>/Engine/Source/Editor/UnrealEd/Private/Fbx/FbxFactory.cpp:449
Scope (from outer to inner):
file
function UObject* UFbxFactory::FactoryCreateFile
Source code excerpt:
FbxImporter->ApplyTransformSettingsToFbxNode(RootNodeToImport, ImportUI->StaticMeshImportData);
if( bCombineMeshes && !bImportStaticMeshLODs )
{
// If Combine meshes and dont import mesh LODs, the interesting node count should be 1 so all the meshes are grouped together into one static mesh
InterestingNodeCount = 1;
}
else
{
// count meshes in lod groups if we dont care about importing LODs
bool bCountLODGroupMeshes = !bImportStaticMeshLODs && bCombineMeshes;
int32 NumLODGroups = 0;
InterestingNodeCount = FbxImporter->GetFbxMeshCount(RootNodeToImport,bCountLODGroupMeshes,NumLODGroups);
// if there were LODs in the file, do not combine meshes even if requested
if( bImportStaticMeshLODs && bCombineMeshes && NumLODGroups > 0)
{
bCombineMeshes = false;
//Combine all the LOD together and export one mesh with LODs
bCombineMeshesLOD = true;
}
}
//Find all collision models, even the one contain under a LOD Group
FbxImporter->FillFbxCollisionMeshArray(RootNodeToImport);
#Loc: <Workspace>/Engine/Source/Editor/UnrealEd/Private/Fbx/FbxFactory.cpp:489
Scope (from outer to inner):
file
function UObject* UFbxFactory::FactoryCreateFile
Source code excerpt:
{
UStaticMesh* NewStaticMesh = NULL;
if (bCombineMeshes)
{
TArray<FbxNode*> FbxMeshArray;
FbxImporter->FillFbxMeshArray(RootNodeToImport, FbxMeshArray, FbxImporter);
if (FbxMeshArray.Num() > 0)
{
NewStaticMesh = FbxImporter->ImportStaticMeshAsSingle(InParent, FbxMeshArray, Name, Flags, ImportUI->StaticMeshImportData, NULL, 0, nullptr);
#Loc: <Workspace>/Engine/Source/Editor/UnrealEd/Private/Fbx/FbxFactory.cpp:601
Scope (from outer to inner):
file
function UObject* UFbxFactory::FactoryCreateFile
Source code excerpt:
}
}
else // !bCombineMeshes && !bCombineMeshesLOD
{
FFormatNamedArguments Args;
Args.Add(TEXT("NodeIndex"), 1);
Args.Add(TEXT("ArrayLength"), InterestingNodeCount);
FScopedSlowTask ImportNodeSlowTask(InterestingNodeCount, GetImportTaskText(FText::Format(NSLOCTEXT("UnrealEd", "Importingf", "Importing ({NodeIndex} of {ArrayLength})"), Args)));
ImportNodeSlowTask.MakeDialog(true);
#Loc: <Workspace>/Engine/Source/Editor/UnrealEd/Private/Fbx/FbxFactory.cpp:1597
Scope (from outer to inner):
file
namespace ImportCompareHelper
function void FillStaticMeshCompareData
Source code excerpt:
TArray<FbxNode*> FbxMeshArray;
bool bImportStaticMeshLODs = ImportUI->StaticMeshImportData->bImportMeshLODs;
bool bCombineMeshes = ImportUI->StaticMeshImportData->bCombineMeshes;
bool bCombineMeshesLOD = false;
TArray<TArray<FbxNode*>> FbxMeshesLod;
FbxNode* Node = nullptr;
if (bCombineMeshes && !bImportStaticMeshLODs)
{
FFbxImporter->FillFbxMeshArray(FFbxImporter->Scene->GetRootNode(), FbxMeshArray, FFbxImporter);
}
else
{
// count meshes in lod groups if we dont care about importing LODs
bool bCountLODGroupMeshes = !bImportStaticMeshLODs && bCombineMeshes;
int32 NumLODGroups = 0;
FFbxImporter->GetFbxMeshCount(FFbxImporter->Scene->GetRootNode(), bCountLODGroupMeshes, NumLODGroups);
// if there were LODs in the file, do not combine meshes even if requested
if (bImportStaticMeshLODs && bCombineMeshes && NumLODGroups > 0)
{
TArray<FbxNode*> FbxLodGroups;
FFbxImporter->FillFbxMeshAndLODGroupArray(FFbxImporter->Scene->GetRootNode(), FbxLodGroups, FbxMeshArray);
FbxMeshesLod.Add(FbxMeshArray);
for (FbxNode* LODGroup : FbxLodGroups)
{
#Loc: <Workspace>/Engine/Source/Editor/UnrealEd/Private/Fbx/FbxFactory.cpp:1645
Scope (from outer to inner):
file
namespace ImportCompareHelper
function void FillStaticMeshCompareData
Source code excerpt:
}
bCombineMeshesLOD = true;
bCombineMeshes = false;
//Set the first LOD
FbxMeshArray = FbxMeshesLod[0];
}
else
{
FFbxImporter->FillFbxMeshArray(FFbxImporter->Scene->GetRootNode(), FbxMeshArray, FFbxImporter);
#Loc: <Workspace>/Engine/Source/Editor/UnrealEd/Private/Fbx/FbxFactory.cpp:1661
Scope (from outer to inner):
file
namespace ImportCompareHelper
function void FillStaticMeshCompareData
Source code excerpt:
Node = FbxMeshArray[0];
}
else if (!bCombineMeshes && !bCombineMeshesLOD)
{
Node = FFbxImporter->GetMeshNodesFromName(StaticMesh->GetName(), FbxMeshArray);
}
// If there is no match it may be because an LOD group was imported where
// the mesh name does not match the file name. This is actually the common case.
#Loc: <Workspace>/Engine/Source/Editor/UnrealEd/Private/Fbx/FbxMainImport.cpp:487
Scope (from outer to inner):
file
namespace UnFbx
function void ApplyImportUIToImportOptions
Source code excerpt:
//Static mesh unshared options
{
InOutImportOptions.bCombineToSingle = ImportUI->StaticMeshImportData->bCombineMeshes;
InOutImportOptions.bRemoveDegenerates = ImportUI->StaticMeshImportData->bRemoveDegenerates;
InOutImportOptions.bBuildReversedIndexBuffer = ImportUI->StaticMeshImportData->bBuildReversedIndexBuffer;
InOutImportOptions.bGenerateLightmapUVs = ImportUI->StaticMeshImportData->bGenerateLightmapUVs;
InOutImportOptions.bOneConvexHullPerUCX = ImportUI->StaticMeshImportData->bOneConvexHullPerUCX;
InOutImportOptions.bAutoGenerateCollision = ImportUI->StaticMeshImportData->bAutoGenerateCollision;
InOutImportOptions.StaticMeshLODGroup = ImportUI->StaticMeshImportData->StaticMeshLODGroup;
#Loc: <Workspace>/Engine/Source/Editor/UnrealEd/Private/Fbx/FbxStaticMeshImport.cpp:1436
Scope (from outer to inner):
file
function UStaticMesh* UnFbx::FFbxImporter::ReimportStaticMesh
Source code excerpt:
// get meshes in Fbx file
bool bImportStaticMeshLODs = ImportOptions->bImportStaticMeshLODs;
bool bCombineMeshes = ImportOptions->bCombineToSingle;
bool bCombineMeshesLOD = false;
TArray<TArray<FbxNode*>> FbxMeshesLod;
if (bCombineMeshes && !bImportStaticMeshLODs)
{
//the function also fill the collision models, so we can update collision models correctly
FillFbxMeshArray(Scene->GetRootNode(), FbxMeshArray, this);
}
else
{
// count meshes in lod groups if we dont care about importing LODs
bool bCountLODGroupMeshes = !bImportStaticMeshLODs && bCombineMeshes;
int32 NumLODGroups = 0;
GetFbxMeshCount(Scene->GetRootNode(), bCountLODGroupMeshes, NumLODGroups);
// if there were LODs in the file, do not combine meshes even if requested
if (bImportStaticMeshLODs && bCombineMeshes && NumLODGroups > 0)
{
TArray<FbxNode*> FbxLodGroups;
FillFbxMeshAndLODGroupArray(Scene->GetRootNode(), FbxLodGroups, FbxMeshArray);
FbxMeshesLod.Add(FbxMeshArray);
for (FbxNode* LODGroup : FbxLodGroups)
#Loc: <Workspace>/Engine/Source/Editor/UnrealEd/Private/Fbx/FbxStaticMeshImport.cpp:1492
Scope (from outer to inner):
file
function UStaticMesh* UnFbx::FFbxImporter::ReimportStaticMesh
Source code excerpt:
}
bCombineMeshesLOD = true;
bCombineMeshes = false;
//Set the first LOD
FbxMeshArray = FbxMeshesLod[0];
}
else
{
FillFbxMeshArray(Scene->GetRootNode(), FbxMeshArray, this);
#Loc: <Workspace>/Engine/Source/Editor/UnrealEd/Private/Fbx/FbxStaticMeshImport.cpp:1508
Scope (from outer to inner):
file
function UStaticMesh* UnFbx::FFbxImporter::ReimportStaticMesh
Source code excerpt:
Node = FbxMeshArray[0];
}
else if(!bCombineMeshes && !bCombineMeshesLOD)
{
Node = GetMeshNodesFromName(Mesh->GetName(), FbxMeshArray);
}
// If there is no match it may be because an LOD group was imported where
// the mesh name does not match the file name. This is actually the common case.