bOneConvexHullPerUCX
bOneConvexHullPerUCX
#Overview
name: bOneConvexHullPerUCX
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 19 C++ source files.
#Summary
#Usage in the C++ source code
The purpose of bOneConvexHullPerUCX is to control the collision generation for static meshes during the import process in Unreal Engine. Specifically, it determines how convex hulls are created for UCX (Unreal Collision X) meshes.
This setting variable is primarily used by the static mesh import system, which is part of the Unreal Engine’s asset import pipeline. Based on the details in the Callsites section, it’s utilized in the following subsystems and modules:
- Interchange Editor Plugin
- Interchange Runtime Plugin
- UnrealEd (Unreal Editor)
- FBX import system
The value of this variable is typically set in the import options for static meshes. It can be configured through the FBX import UI, scene import options, or programmatically when setting up import data.
This variable interacts with other import-related variables, such as bImportCollision, bAutoGenerateCollision, and other static mesh import settings.
Developers should be aware of the following when using this variable:
- When set to true, each UCX collision mesh will be imported as a single convex hull.
- When set to false, a UCX mesh will be decomposed into separate pieces, and a convex hull will be generated for each piece.
- This setting only applies to meshes with names prefixed with “UCX” or “MCDCX”.
Best practices when using this variable include:
- Consider the complexity of your collision meshes. For simple shapes, setting this to true can be more efficient.
- For more complex collision requirements, setting this to false allows for more detailed collision representation at the cost of performance.
- Ensure that your UCX meshes are properly named and structured in your 3D modeling software before import.
- Test the collision behavior with both settings to determine which works best for your specific use case.
- Remember that this setting affects import-time behavior, so you may need to reimport assets if you change this setting.
#Setting Variables
#References In INI files
Location: <Workspace>/Engine/Config/BaseEditorPerProjectUserSettings.ini:661, section: [/Script/UnrealEd.FbxStaticMeshImportData]
- INI Section:
/Script/UnrealEd.FbxStaticMeshImportData - Raw value:
True - 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:153
Scope (from outer to inner):
file
namespace UE::Interchange::Private
function void FillInterchangeGenericAssetsPipelineFromFbxStaticMeshImportData
Source code excerpt:
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)
{
GenericAssetPipeline->CommonMeshesProperties->VertexColorImportOption = EInterchangeVertexColorImportOption::IVCIO_Ignore;
#Loc: <Workspace>/Engine/Plugins/Interchange/Editor/Source/InterchangeEditor/Private/InterchangeFbxAssetImportDataConverter.cpp:318
Scope (from outer to inner):
file
namespace UE::Interchange::Private
function UAssetImportData* ConvertToLegacyFbx
Source code excerpt:
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)
{
DestinationStaticMeshImportData->VertexColorImportOption = EVertexColorImportOption::Ignore;
#Loc: <Workspace>/Engine/Plugins/Interchange/Runtime/Source/Import/Private/Mesh/InterchangeStaticMeshFactory.cpp:1527
Scope (from outer to inner):
file
function bool UInterchangeStaticMeshFactory::ImportConvexCollision
Source code excerpt:
TArray<FMeshPayload> MeshPayloads = GetMeshPayloads(Arguments, ConvexCollisionMeshUids);
bool bOneConvexHullPerUCX;
if (!LodDataNode->GetOneConvexHullPerUCX(bOneConvexHullPerUCX) || !bOneConvexHullPerUCX)
{
for (const FMeshPayload& MeshPayload : MeshPayloads)
{
const FTransform& Transform = FTransform::Identity;
const TOptional<FMeshPayloadData>& PayloadData = MeshPayload.PayloadData.Get();
#Loc: <Workspace>/Engine/Plugins/Interchange/Runtime/Source/Pipelines/Private/InterchangeGenericStaticMeshPipeline.cpp:491
Scope (from outer to inner):
file
function UInterchangeStaticMeshLodDataNode* UInterchangeGenericMeshPipeline::CreateStaticMeshLodDataNode
Source code excerpt:
StaticMeshLodDataNode->InitializeNode(NodeUID, DisplayLabel, EInterchangeNodeContainerType::FactoryData);
StaticMeshLodDataNode->SetOneConvexHullPerUCX(bOneConvexHullPerUCX);
StaticMeshLodDataNode->SetImportCollision(bImportCollision);
BaseNodeContainer->AddNode(StaticMeshLodDataNode);
return StaticMeshLodDataNode;
}
#Loc: <Workspace>/Engine/Plugins/Interchange/Runtime/Source/Pipelines/Public/InterchangeGenericMeshPipeline.h:73
Scope (from outer to inner):
file
class class UInterchangeGenericMeshPipeline : public UInterchangePipelineBase
Source code excerpt:
/** If enabled, each UCX collision mesh will be imported as a single convex hull. If disabled, a UCX mesh will be decomposed into its separate pieces and a convex hull generated for each. */
UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Static Meshes", meta = (SubCategory = "Collision", editcondition = "bImportCollision && bImportCollisionAccordingToMeshName"))
bool bOneConvexHullPerUCX = true;
////// Static Meshes Build settings Properties //////
/** If enabled, imported meshes will be rendered by Nanite at runtime. Make sure your meshes and materials meet the requirements for Nanite. */
UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Static Meshes", meta = (SubCategory = "Build"))
bool bBuildNanite = false;
#Loc: <Workspace>/Engine/Plugins/Tests/EditorTests/Source/EditorTests/Private/UnrealEd/FbxAutomationTests.cpp:385
Scope (from outer to inner):
file
function BEGIN_FUNCTION_BUILD_OPTIMIZATION bool F
Source code excerpt:
ImportData->bBuildReversedIndexBuffer = TestPlan->ImportUI->StaticMeshImportData->bBuildReversedIndexBuffer;
ImportData->bGenerateLightmapUVs = TestPlan->ImportUI->StaticMeshImportData->bGenerateLightmapUVs;
ImportData->bOneConvexHullPerUCX = TestPlan->ImportUI->StaticMeshImportData->bOneConvexHullPerUCX;
ImportData->bAutoGenerateCollision = TestPlan->ImportUI->StaticMeshImportData->bAutoGenerateCollision;
//Copy UFbxMeshImportData
ImportData->bTransformVertexToAbsolute = TestPlan->ImportUI->StaticMeshImportData->bTransformVertexToAbsolute;
ImportData->bBakePivotInVertex = TestPlan->ImportUI->StaticMeshImportData->bBakePivotInVertex;
ImportData->bImportMeshLODs = TestPlan->ImportUI->StaticMeshImportData->bImportMeshLODs;
ImportData->NormalImportMethod = TestPlan->ImportUI->StaticMeshImportData->NormalImportMethod;
#Loc: <Workspace>/Engine/Plugins/Tests/EditorTests/Source/EditorTests/Private/UnrealEd/FbxAutomationTests.cpp:493
Scope (from outer to inner):
file
function BEGIN_FUNCTION_BUILD_OPTIMIZATION bool F
Source code excerpt:
ImportData->bBuildReversedIndexBuffer = TestPlan->ImportUI->StaticMeshImportData->bBuildReversedIndexBuffer;
ImportData->bGenerateLightmapUVs = TestPlan->ImportUI->StaticMeshImportData->bGenerateLightmapUVs;
ImportData->bOneConvexHullPerUCX = TestPlan->ImportUI->StaticMeshImportData->bOneConvexHullPerUCX;
ImportData->bAutoGenerateCollision = TestPlan->ImportUI->StaticMeshImportData->bAutoGenerateCollision;
//Copy UFbxMeshImportData
ImportData->bTransformVertexToAbsolute = TestPlan->ImportUI->StaticMeshImportData->bTransformVertexToAbsolute;
ImportData->bBakePivotInVertex = TestPlan->ImportUI->StaticMeshImportData->bBakePivotInVertex;
ImportData->bImportMeshLODs = TestPlan->ImportUI->StaticMeshImportData->bImportMeshLODs;
ImportData->NormalImportMethod = TestPlan->ImportUI->StaticMeshImportData->NormalImportMethod;
#Loc: <Workspace>/Engine/Source/Editor/UnrealEd/Classes/Factories/FbxSceneImportOptionsStaticMesh.h:77
Scope (from outer to inner):
file
class class UFbxSceneImportOptionsStaticMesh : public UObject
Source code excerpt:
/** If checked, one convex hull per UCX_ prefixed collision mesh will be generated instead of decomposing into multiple hulls */
UPROPERTY(EditAnywhere, config, Category = StaticMesh)
uint32 bOneConvexHullPerUCX : 1;
/** Enabling this option will read the tangents(tangent,binormal,normal) from FBX file instead of generating them automatically. */
UPROPERTY(EditAnywhere, config, Category = StaticMesh)
EFBXSceneNormalImportMethod NormalImportMethod;
/** Use the MikkTSpace tangent space generator for generating normals and tangents on the mesh */
#Loc: <Workspace>/Engine/Source/Editor/UnrealEd/Classes/Factories/FbxStaticMeshImportData.h:46
Scope (from outer to inner):
file
class class UFbxStaticMeshImportData : public UFbxMeshImportData
Source code excerpt:
/** If checked, one convex hull per UCX_ prefixed collision mesh will be generated instead of decomposing into multiple hulls */
UPROPERTY(EditAnywhere, BlueprintReadWrite, AdvancedDisplay, config, Category= Mesh, meta=(OBJRestrict="true", ImportType="StaticMesh"))
uint32 bOneConvexHullPerUCX:1;
/** If checked, collision will automatically be generated (ignored if custom collision is imported or used). */
UPROPERTY(EditAnywhere, BlueprintReadWrite, config, Category = Mesh, meta=(OBJRestrict="true", ImportType="StaticMesh", DisplayName="Generate Missing Collision"))
uint32 bAutoGenerateCollision : 1;
/** For static meshes, enabling this option will combine all meshes in the FBX into a single monolithic mesh in Unreal */
#Loc: <Workspace>/Engine/Source/Editor/UnrealEd/Private/Fbx/FbxMainImport.cpp:491
Scope (from outer to inner):
file
namespace UnFbx
function void ApplyImportUIToImportOptions
Source code excerpt:
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;
}
// animation unshared options
{
#Loc: <Workspace>/Engine/Source/Editor/UnrealEd/Private/Fbx/FbxSceneImportData.cpp:104
Scope (from outer to inner):
file
function UnFbx::FBXImportOptions *JSONToFbxOption
Source code excerpt:
OptionObj->TryGetBoolField(TEXT("bBuildReversedIndexBuffer"), Option->bBuildReversedIndexBuffer);
OptionObj->TryGetBoolField(TEXT("bGenerateLightmapUVs"), Option->bGenerateLightmapUVs);
OptionObj->TryGetBoolField(TEXT("bOneConvexHullPerUCX"), Option->bOneConvexHullPerUCX);
OptionObj->TryGetBoolField(TEXT("bAutoGenerateCollision"), Option->bAutoGenerateCollision);
FString LODGroup;
if (OptionObj->TryGetStringField(TEXT("StaticMeshLODGroup"), LODGroup))
{
Option->StaticMeshLODGroup = FName(*LODGroup);
}
#Loc: <Workspace>/Engine/Source/Editor/UnrealEd/Private/Fbx/FbxSceneImportData.cpp:199
Scope (from outer to inner):
file
function FString FbxOptionToJSON
Source code excerpt:
Option->bBuildReversedIndexBuffer ? 1 : 0,
Option->bGenerateLightmapUVs ? 1 : 0,
Option->bOneConvexHullPerUCX ? 1 : 0,
Option->bAutoGenerateCollision ? 1 : 0,
*(Option->StaticMeshLODGroup.ToString()),
Option->bImportStaticMeshLODs ? 1 : 0
);
JsonString += FString::Printf(TEXT("\"bUpdateSkeletonReferencePose\" : \"%d\", \"bUseT0AsRefPose\" : \"%d\", \"bPreserveSmoothingGroups\" : \"%d\", \"bKeepSectionsSeparate\" : \"%d\", \"bImportMeshesInBoneHierarchy\" : \"%d\", \"bImportMorphTargets\" : \"%d\", , \"bImportVertexAttributes\" : \"%d\", \"OverlappingThresholds\" : {\"ThresholdPosition\" : \"%f\", \"ThresholdTangentNormal\" : \"%f\", \"ThresholdUV\" : \"%f\", \"MorphThresholdPosition\" : \"%f\"},"),
#Loc: <Workspace>/Engine/Source/Editor/UnrealEd/Private/Fbx/FbxSceneImportOptionsStaticMesh.cpp:20
Scope (from outer to inner):
file
function UFbxSceneImportOptionsStaticMesh::UFbxSceneImportOptionsStaticMesh
Source code excerpt:
, bBuildReversedIndexBuffer(true)
, bGenerateLightmapUVs(true)
, bOneConvexHullPerUCX(true)
{
VertexOverrideColor = FColor(255, 255, 255, 255);
NormalImportMethod = EFBXSceneNormalImportMethod::FBXSceneNIM_ComputeNormals;
NormalGenerationMethod = EFBXSceneNormalGenerationMethod::MikkTSpace;
}
#Loc: <Workspace>/Engine/Source/Editor/UnrealEd/Private/Fbx/FbxSceneImportOptionsStaticMesh.cpp:34
Scope (from outer to inner):
file
function void UFbxSceneImportOptionsStaticMesh::FillStaticMeshInmportData
Source code excerpt:
StaticMeshImportData->bBuildReversedIndexBuffer = bBuildReversedIndexBuffer;
StaticMeshImportData->bGenerateLightmapUVs = bGenerateLightmapUVs;
StaticMeshImportData->bOneConvexHullPerUCX = bOneConvexHullPerUCX;
StaticMeshImportData->bRemoveDegenerates = bRemoveDegenerates;
StaticMeshImportData->StaticMeshLODGroup = StaticMeshLODGroup;
switch (VertexColorImportOption)
{
case EFbxSceneVertexColorImportOption::Ignore:
StaticMeshImportData->VertexColorImportOption = EVertexColorImportOption::Ignore;
#Loc: <Workspace>/Engine/Source/Editor/UnrealEd/Private/Fbx/FbxStaticMeshImport.cpp:2871
Scope (from outer to inner):
file
function bool UnFbx::FFbxImporter::ImportCollisionModels
Source code excerpt:
if ( ModelName.Find("UCX") != -1 || ModelName.Find("MCDCX") != -1 )
{
if( !ImportOptions->bOneConvexHullPerUCX )
{
if (StaticMeshImportUtils::DecomposeUCXMesh(CollisionVertices, CollisionFaceIdx, StaticMesh->GetBodySetup()))
{
bAtLeastOneCollisionMeshImported = true;
}
else
#Loc: <Workspace>/Engine/Source/Editor/UnrealEd/Private/Fbx/FbxStaticMeshImportData.cpp:11
Scope (from outer to inner):
file
function UFbxStaticMeshImportData::UFbxStaticMeshImportData
Source code excerpt:
bBuildNanite = false;
bGenerateLightmapUVs = true;
bOneConvexHullPerUCX = true;
bAutoGenerateCollision = true;
bTransformVertexToAbsolute = true;
bBakePivotInVertex = false;
VertexOverrideColor = FColor(255, 255, 255, 255);
DistanceFieldResolutionScale = 1.0f;
}
#Loc: <Workspace>/Engine/Source/Editor/UnrealEd/Private/Fbx/SFbxSceneOptionWindow.cpp:1404
Scope (from outer to inner):
file
function void SFbxSceneOptionWindow::CopyStaticMeshOptionsToFbxOptions
Source code excerpt:
ImportSettings->bBuildReversedIndexBuffer = StaticMeshOptions->bBuildReversedIndexBuffer;
ImportSettings->bGenerateLightmapUVs = StaticMeshOptions->bGenerateLightmapUVs;
ImportSettings->bOneConvexHullPerUCX = StaticMeshOptions->bOneConvexHullPerUCX;
ImportSettings->bRemoveDegenerates = StaticMeshOptions->bRemoveDegenerates;
ImportSettings->StaticMeshLODGroup = StaticMeshOptions->StaticMeshLODGroup;
switch (StaticMeshOptions->VertexColorImportOption)
{
case EFbxSceneVertexColorImportOption::Replace:
ImportSettings->VertexColorImportOption = EVertexColorImportOption::Type::Replace;
#Loc: <Workspace>/Engine/Source/Editor/UnrealEd/Private/Fbx/SFbxSceneOptionWindow.cpp:1450
Scope (from outer to inner):
file
function void SFbxSceneOptionWindow::CopyFbxOptionsToStaticMeshOptions
Source code excerpt:
StaticMeshOptions->bBuildReversedIndexBuffer = ImportSettings->bBuildReversedIndexBuffer;
StaticMeshOptions->bGenerateLightmapUVs = ImportSettings->bGenerateLightmapUVs;
StaticMeshOptions->bOneConvexHullPerUCX = ImportSettings->bOneConvexHullPerUCX;
StaticMeshOptions->bRemoveDegenerates = ImportSettings->bRemoveDegenerates;
StaticMeshOptions->StaticMeshLODGroup = ImportSettings->StaticMeshLODGroup;
switch (ImportSettings->VertexColorImportOption)
{
case EVertexColorImportOption::Type::Replace:
StaticMeshOptions->VertexColorImportOption = EFbxSceneVertexColorImportOption::Replace;
#Loc: <Workspace>/Engine/Source/Editor/UnrealEd/Public/FbxImporter.h:153
Scope (from outer to inner):
file
namespace UnFbx
Source code excerpt:
bool bBuildNanite;
bool bGenerateLightmapUVs;
bool bOneConvexHullPerUCX;
bool bAutoGenerateCollision;
FName StaticMeshLODGroup;
bool bImportStaticMeshLODs;
bool bAutoComputeLodDistances;
TArray<float> LodDistances;
int32 MinimumLodNumber;