FSkeletalMeshOperations Class Reference

#include <SkeletalMeshOperations.h>

Inheritance diagram for FSkeletalMeshOperations:

Classes
struct	FSkeletalMeshAppendSettings

Static Public Member Functions
static SKELETALMESHDESCRIPTION_API void	AppendSkinWeight (const FMeshDescription &SourceMesh, FMeshDescription &TargetMesh, FSkeletalMeshAppendSettings &AppendSettings)
static SKELETALMESHDESCRIPTION_API bool	CopySkinWeightAttributeFromMesh (const FMeshDescription &InSourceMesh, FMeshDescription &InTargetMesh, const FName InSourceProfile, const FName InTargetProfile, const TMap< int32, int32 > *SourceBoneIndexToTargetBoneIndexMap)
static SKELETALMESHDESCRIPTION_API bool	RemapBoneIndicesOnSkinWeightAttribute (FMeshDescription &InMesh, TConstArrayView< int32 > InBoneIndexMapping)
static SKELETALMESHDESCRIPTION_API bool	GetPosedMesh (const FMeshDescription &InSourceMesh, FMeshDescription &OutTargetMesh, TConstArrayView< FTransform > InComponentSpaceTransforms, const FName InSkinWeightProfile=NAME_None, const TMap< FName, float > &InMorphTargetWeights={})
static SKELETALMESHDESCRIPTION_API bool	GetPosedMesh (const FMeshDescription &InSourceMesh, FMeshDescription &OutTargetMesh, const TMap< FName, FTransform > &InBoneSpaceTransforms, const FName InSkinWeightProfile=NAME_None, const TMap< FName, float > &InMorphTargetWeights={})
static SKELETALMESHDESCRIPTION_API bool	GetPosedMeshInPlace (FMeshDescription &InOutTargetMesh, TConstArrayView< FTransform > InComponentSpaceTransforms, const FName InSkinWeightProfile=NAME_None, const TMap< FName, float > &InMorphTargetWeights={}, bool bInSkipRecomputeNormalsTangents=false, bool bInWriteBonePose=false)
static SKELETALMESHDESCRIPTION_API bool	GetUnposedMesh (const FMeshDescription &InPosedMesh, const FMeshDescription &InRefMesh, TArray< FTransform > &RefBoneTransforms, FMeshDescription &OutUnposedMesh, TConstArrayView< FTransform > InComponentSpaceTransforms, const FName InSkinWeightProfile, const TMap< FName, float > &InMorphTargetWeights)
static SKELETALMESHDESCRIPTION_API bool	GetUnposedMeshInPlace (FMeshDescription &InOutTargetMesh, const FMeshDescription &InRefMesh, TArray< FTransform > &RefBoneTransforms, TConstArrayView< FTransform > InComponentSpaceTransforms, const FName InSkinWeightProfile, const TMap< FName, float > &InMorphTargetWeights, bool bInWriteBonePose=false)
static SKELETALMESHDESCRIPTION_API void	ConvertHardEdgesToSmoothMasks (const FMeshDescription &InMeshDescription, TArray< uint32 > &OutSmoothMasks)
static SKELETALMESHDESCRIPTION_API void	FixVertexInstanceStructure (FMeshDescription &SourceMeshDescription, FMeshDescription &TargetMeshDescription, const TArray< uint32 > &SourceSmoothingMasks, TArray< uint32 > &TargetFaceSmoothingMasks)
static SKELETALMESHDESCRIPTION_API void	ValidateFixComputeMeshDescriptionData (FMeshDescription &MeshDescription, const TArray< uint32 > &FaceSmoothingMasks, int32 LODIndex, const bool bComputeWeightedNormals, const FString &SkeletalMeshPath)
static SKELETALMESHDESCRIPTION_API void	ValidateAndFixInfluences (FMeshDescription &MeshDescription, bool &bOutInfluenceCountLimitHit)
static SKELETALMESHDESCRIPTION_API void	ApplyRigToGeo (FMeshDescription &RigMeshDescription, FMeshDescription &GeoMeshDescription)
Static Public Member Functions inherited from FStaticMeshOperations
static STATICMESHDESCRIPTION_API void	ComputeTriangleTangentsAndNormals (FMeshDescription &MeshDescription, float ComparisonThreshold=0.0f, const TCHAR *DebugName=nullptr)
static STATICMESHDESCRIPTION_API void	ComputeTangentsAndNormals (FMeshDescription &MeshDescription, EComputeNTBsFlags ComputeNTBsOptions)
static STATICMESHDESCRIPTION_API void	RecomputeNormalsAndTangentsIfNeeded (FMeshDescription &MeshDescription, EComputeNTBsFlags ComputeNTBsOptions)
static STATICMESHDESCRIPTION_API void	ComputeMikktTangents (FMeshDescription &MeshDescription, bool bIgnoreDegenerateTriangles)
static STATICMESHDESCRIPTION_API void	DetermineEdgeHardnessesFromVertexInstanceNormals (FMeshDescription &MeshDescription, float Tolerance=UE_KINDA_SMALL_NUMBER)
static STATICMESHDESCRIPTION_API void	ConvertToRawMesh (const FMeshDescription &SourceMeshDescription, FRawMesh &DestinationRawMesh, const TMap< FName, int32 > &MaterialMap)
static STATICMESHDESCRIPTION_API void	ConvertFromRawMesh (const FRawMesh &SourceRawMesh, FMeshDescription &DestinationMeshDescription, const TMap< int32, FName > &MaterialMap, bool bSkipNormalsAndTangents=false, const TCHAR *DebugName=nullptr)
static STATICMESHDESCRIPTION_API void	AppendMeshDescription (const FMeshDescription &SourceMesh, FMeshDescription &TargetMesh, const FAppendSettings &AppendSettings)
static STATICMESHDESCRIPTION_API void	AppendMeshDescriptions (const TArray< const FMeshDescription * > &SourceMeshes, FMeshDescription &TargetMesh, const FAppendSettings &AppendSettings)
static STATICMESHDESCRIPTION_API void	HasInvalidVertexInstanceNormalsOrTangents (const FMeshDescription &MeshDescription, bool &bHasInvalidNormals, bool &bHasInvalidTangents)
static void	AreNormalsAndTangentsValid (const FMeshDescription &MeshDescription, bool &bHasInvalidNormals, bool &bHasInvalidTangents)
static STATICMESHDESCRIPTION_API void	FindOverlappingCorners (FOverlappingCorners &OverlappingCorners, const FMeshDescription &MeshDescription, float ComparisonThreshold)
static STATICMESHDESCRIPTION_API int32	GetUVChartCount (FMeshDescription &MeshDescription, int32 SrcLightmapIndex, ELightmapUVVersion LightmapUVVersion, const FOverlappingCorners &OverlappingCorners)
static STATICMESHDESCRIPTION_API bool	CreateLightMapUVLayout (FMeshDescription &MeshDescription, int32 SrcLightmapIndex, int32 DstLightmapIndex, int32 MinLightmapResolution, ELightmapUVVersion LightmapUVVersion, const FOverlappingCorners &OverlappingCorners)
static STATICMESHDESCRIPTION_API bool	GenerateUniqueUVsForStaticMesh (const FMeshDescription &MeshDescription, int32 TextureResolution, bool bMergeIdenticalMaterials, TArray< FVector2D > &OutTexCoords)
static STATICMESHDESCRIPTION_API bool	GenerateUV (const FMeshDescription &MeshDescription, const FGenerateUVOptions &Options, TArray< FVector2D > &OutTexCoords)
static STATICMESHDESCRIPTION_API bool	AddUVChannel (FMeshDescription &MeshDescription)
static STATICMESHDESCRIPTION_API bool	InsertUVChannel (FMeshDescription &MeshDescription, int32 UVChannelIndex)
static STATICMESHDESCRIPTION_API bool	RemoveUVChannel (FMeshDescription &MeshDescription, int32 UVChannelIndex)
static STATICMESHDESCRIPTION_API void	GeneratePlanarUV (const FMeshDescription &MeshDescription, const FUVMapParameters &Params, TMap< FVertexInstanceID, FVector2D > &OutTexCoords)
static STATICMESHDESCRIPTION_API void	GenerateCylindricalUV (FMeshDescription &MeshDescription, const FUVMapParameters &Params, TMap< FVertexInstanceID, FVector2D > &OutTexCoords)
static STATICMESHDESCRIPTION_API void	GenerateBoxUV (const FMeshDescription &MeshDescription, const FUVMapParameters &Params, TMap< FVertexInstanceID, FVector2D > &OutTexCoords)
static STATICMESHDESCRIPTION_API void	SwapPolygonPolygonGroup (FMeshDescription &MeshDescription, int32 SectionIndex, int32 TriangleIndexStart, int32 TriangleIndexEnd, bool bRemoveEmptyPolygonGroup)
static STATICMESHDESCRIPTION_API void	ConvertHardEdgesToSmoothGroup (const FMeshDescription &SourceMeshDescription, TArray< uint32 > &FaceSmoothingMasks)
static STATICMESHDESCRIPTION_API void	ConvertSmoothGroupToHardEdges (const TArray< uint32 > &FaceSmoothingMasks, FMeshDescription &DestinationMeshDescription)
static STATICMESHDESCRIPTION_API bool	HasVertexColor (const FMeshDescription &MeshDescription)
static STATICMESHDESCRIPTION_API void	BuildWeldedVertexIDRemap (const FMeshDescription &MeshDescription, const float WeldingThreshold, TMap< FVertexID, FVertexID > &OutVertexIDRemap)
static STATICMESHDESCRIPTION_API FSHAHash	ComputeSHAHash (const FMeshDescription &MeshDescription, bool bSkipTransientAttributes=false)
static STATICMESHDESCRIPTION_API void	FlipPolygons (FMeshDescription &MeshDescription)
static STATICMESHDESCRIPTION_API void	ApplyTransform (FMeshDescription &MeshDescription, const FTransform &Transform, bool bApplyCorrectNormalTransform=false)
static STATICMESHDESCRIPTION_API void	ApplyTransform (FMeshDescription &MeshDescription, const FMatrix &Transform, bool bApplyCorrectNormalTransform=false)
static STATICMESHDESCRIPTION_API int32	GetUniqueVertexCount (const FMeshDescription &MeshDescription)
static STATICMESHDESCRIPTION_API int32	GetUniqueVertexCount (const FMeshDescription &MeshDescription, const FOverlappingCorners &OverlappingCorners)
static STATICMESHDESCRIPTION_API void	ReorderMeshDescriptionPolygonGroups (const FMeshDescription &SourceMeshDescription, FMeshDescription &DestinationMeshDescription, TOptional< const FString > UnmatchMaterialNameWarning, TOptional< const FString > DestinationPolygonGroupCountDifferFromSource_Msg)
static STATICMESHDESCRIPTION_API bool	ValidateAndFixData (FMeshDescription &MeshDescription, const FString &DebugName)
static STATICMESHDESCRIPTION_API float	ComputeMeshArea (const FMeshDescription &InMeshDescription)

Additional Inherited Members
Public Types inherited from FStaticMeshOperations
enum class	EGenerateUVMethod {   Default , Legacy , UVAtlas , XAtlas ,   PatchBuilder }

Member Function Documentation

AppendSkinWeight()

void FSkeletalMeshOperations::AppendSkinWeight ( const FMeshDescription &  SourceMesh, FMeshDescription &  TargetMesh, FSkeletalMeshAppendSettings &  AppendSettings  )

static

ApplyRigToGeo()

void FSkeletalMeshOperations::ApplyRigToGeo ( FMeshDescription &  RigMeshDescription, FMeshDescription &  GeoMeshDescription  )

static

Applies the Rig / Skinning found in RigMeshDescription to the Geometry found in GeomeshDescription Desired behavior of this function was targeting FSkeletalMeshImportData::ApplyRigToGeo. Important distinction however: FSkeletalMeshImportData::ApplyRigToGeo seem to work based on VertexInstances, it also checks the VertexCandidate Normal and UVs and only finds the candidate legitimate if they match between Rig and Geo) As Influences (BoneIndex and BoneWeights) are Vertex (NOT VertexInstance) dependent. Whilst original implementation in FSkeletalMeshImportData::ApplyRigToGeo was checking and validating against normals and UVs for NearestWedges, with current implementation we try the NearestVertices with the same principle as the FindMatchingPositionVertexIndexes. (aka based on GetSmallestDeltaBetweenTriangleLists)

ConvertHardEdgesToSmoothMasks()

void FSkeletalMeshOperations::ConvertHardEdgesToSmoothMasks ( const FMeshDescription &  InMeshDescription, TArray< uint32 > &  OutSmoothMasks  )

static

A simpler variant of FStaticMeshOperations::ConvertHardEdgesToSmoothGroup that assumes that hard edges always form closed regions.

CopySkinWeightAttributeFromMesh()

bool FSkeletalMeshOperations::CopySkinWeightAttributeFromMesh ( const FMeshDescription &  InSourceMesh, FMeshDescription &  InTargetMesh, const FName  InSourceProfile, const FName  InTargetProfile, const TMap< int32, int32 > *  SourceBoneIndexToTargetBoneIndexMap  )

static

Copies skin weight attribute from one mesh to another. Assumes the two geometries are identical or near-identical. Uses closest triangle on the target mesh to interpolate skin weights to each of the points on the target mesh. Attributes for the given profiles on both meshes should exist in order for this function to succeed.

Parameters

InSourceMesh	The mesh to copy skin weights from.
InTargetMesh	The mesh to copy skin weights to.
InSourceProfile	The name of the skin weight profile on the source mesh to read from.
InTargetProfile	The name of the skin weight profile on the target mesh to write to.
SourceBoneIndexToTargetBoneIndexMap	An optional mapping table to map bone indexes on the source mesh to the target mesh. The table needs to be complete for all the source bone indexes to valid target bone indexes, otherwise the behavior is undefined. If the table is not given, the bone indexes on the source and target meshes are assumed to be the same.

FixVertexInstanceStructure()

void FSkeletalMeshOperations::FixVertexInstanceStructure ( FMeshDescription &  SourceMeshDescription, FMeshDescription &  TargetMeshDescription, const TArray< uint32 > &  SourceSmoothingMasks, TArray< uint32 > &  TargetFaceSmoothingMasks  )

static

Helper function to follow behavior generated in FSkeletalMeshImportData::GetMeshDescription, just straight on FMeshDescriptions. FSkeletalMeshImportData::GetMeshDescription makes the VertexInstances a single usage semantics. It also re-orders the vertexInstances to be in a straight increasing sequence, which seems to affect the normal and tangent (FSkeletalMeshOperations::Compute..) generation. (Which means, we can't do the restructuring in place.) For that reason we re-create the MeshDescription into the TargetMeshDescription which is expected to be empty.

GetPosedMesh() [1/2]

bool FSkeletalMeshOperations::GetPosedMesh ( const FMeshDescription &  InSourceMesh, FMeshDescription &  OutTargetMesh, const TMap< FName, FTransform > &  InBoneSpaceTransforms, const FName  InSkinWeightProfile = NAME_None, const TMap< FName, float > &  InMorphTargetWeights = {}  )

static

Returns a mesh in the pose given by the bone-space transforms passed in. The transforms simply replace the matching ref pose transforms stored in the bone data on the mesh. Any named transform, that does not match a bone on the mesh, is ignored.
If there are no skin weights on the mesh, or the named skin weight profile doesn't exist, the function also returns false. The resulting bones on the mesh will have their bone-space transforms updated so that the same mesh can be re-posed as needed.

Parameters

InSourceMesh	The mesh to deform.
OutTargetMesh	The deformed mesh result.
InBoneSpaceTransforms	A map of named bone-space transforms.
InSkinWeightProfile	The skin weight profile to use as the source of skin weights for the deformation.
InMorphTargetWeights	Optional morph target weights to apply. Any morph target that doesn't exist is ignored.

Returns

true if the operation succeeded.

GetPosedMesh() [2/2]

bool FSkeletalMeshOperations::GetPosedMesh ( const FMeshDescription &  InSourceMesh, FMeshDescription &  OutTargetMesh, TConstArrayView< FTransform >  InComponentSpaceTransforms, const FName  InSkinWeightProfile = NAME_None, const TMap< FName, float > &  InMorphTargetWeights = {}  )

static

Returns a mesh in the pose given by the component-space transforms passed in. The list of transforms should match exactly the list of bones stored on the mesh. If not, the function fails and returns false. If there are no skin weights on the mesh, or the named skin weight profile doesn't exist, the function also returns false. The resulting bones on the mesh will have their bone-space transforms updated so that the same mesh can be re-posed as needed.

Parameters

InSourceMesh	The mesh to deform.
OutTargetMesh	The deformed mesh result.
InComponentSpaceTransforms	The component space transforms used to move the mesh joints for deforming, using linear-blend skinning.
InSkinWeightProfile	The skin weight profile to use as the source of skin weights for the deformation.
InMorphTargetWeights	Optional morph target weights to apply. Any morph target that doesn't exist is ignored.

Returns

true if the operation succeeded.

GetPosedMeshInPlace()

bool FSkeletalMeshOperations::GetPosedMeshInPlace ( FMeshDescription &  InOutTargetMesh, TConstArrayView< FTransform >  InComponentSpaceTransforms, const FName  InSkinWeightProfile = NAME_None, const TMap< FName, float > &  InMorphTargetWeights = {}, bool  bInSkipRecomputeNormalsTangents = false, bool  bInWriteBonePose = false  )

static

Returns a mesh in the pose given by the component-space transforms passed in. The list of transforms should match exactly the list of bones stored on the mesh. If not, the function fails and returns false. If there are no skin weights on the mesh, or the named skin weight profile doesn't exist, the function also returns false. if bInWriteBonePose is true, the resulting bones on the mesh will have their bone-space transforms updated so that the same mesh can be re-posed as needed.

Parameters

InOutTargetMesh	rest pose mesh to be deformed in place
InComponentSpaceTransforms	The component space transforms used to move the mesh joints for deforming, using linear-blend skinning.
InSkinWeightProfile	The skin weight profile to use as the source of skin weights for the deformation.
InMorphTargetWeights	Optional morph target weights to apply. Any morph target that doesn't exist is ignored.
bInSkipRecomputeNormalsTangents	skip recompute normals and tangents to improve performance
bInWriteBonePose	whether to write the current bone pose into the mesh description.

Returns

true if the operation succeeded.

GetUnposedMesh()

bool FSkeletalMeshOperations::GetUnposedMesh ( const FMeshDescription &  InPosedMesh, const FMeshDescription &  InRefMesh, TArray< FTransform > &  RefBoneTransforms, FMeshDescription &  OutUnposedMesh, TConstArrayView< FTransform >  InComponentSpaceTransforms, const FName  InSkinWeightProfile, const TMap< FName, float > &  InMorphTargetWeights  )

static

Returns the unposed version of the provided posed mesh

Parameters

InPosedMesh	The posed mesh,
InRefMesh	Ref mesh containing morph target deltas of existing morphs
RefBoneTransforms	Ref component space bone transforms
OutUnposedMesh	The mesh with pose reset to reference
InComponentSpaceTransforms	Current component space bone transforms
InSkinWeightProfile	The skin weight profile to use as the source of skin weights for the deformation.
InMorphTargetWeights	Active morph target weights producing the fully deformed mesh. Don't include the weight of the morph target you want to extract

Returns

true if the operation succeeded.

GetUnposedMeshInPlace()

bool FSkeletalMeshOperations::GetUnposedMeshInPlace ( FMeshDescription &  InOutTargetMesh, const FMeshDescription &  InRefMesh, TArray< FTransform > &  RefBoneTransforms, TConstArrayView< FTransform >  InComponentSpaceTransforms, const FName  InSkinWeightProfile, const TMap< FName, float > &  InMorphTargetWeights, bool  bInWriteBonePose = false  )

static

Returns the unposed version of the provided posed mesh

Parameters

InOutTargetMesh	input is the posed mesh, output is the mesh reset to ref pose
InRefMesh	Ref mesh containing morph target deltas of existing morphs
RefBoneTransforms	Ref component space bone transforms
InComponentSpaceTransforms	Current component space bone transforms
InSkinWeightProfile	The skin weight profile to use as the source of skin weights for the deformation.
InMorphTargetWeights	Active morph target weights producing the fully deformed mesh. Don't include the weight of the morph target you want to extract

Returns

true if the operation succeeded.

RemapBoneIndicesOnSkinWeightAttribute()

bool FSkeletalMeshOperations::RemapBoneIndicesOnSkinWeightAttribute ( FMeshDescription &  InMesh, TConstArrayView< int32 >  InBoneIndexMapping  )

static

Remaps the bone indices on all skin weight attributes from one index to another. The array view should contain a full mapping of all the bone indices contained in the skin weights. The array is indexed by the current bone index and the value at that index is the new bone index. If the mapping is incomplete or if two entries map to the same bone, the result is undefined. No prior checking is performed.

Parameters

InMesh	The mesh on which to modify all skin weight attributes to remap their bone indices.
InBoneIndexMapping	The mapping from one bone index to another. The old bone index is used to index into the array, the value at that position is the new bone index.

Returns

true if the operation was successful. If the mapping array was incomplete then this will return false. If there are no skin weight attributes on the mesh, then the operation is still deemed successful.

ValidateAndFixInfluences()

void FSkeletalMeshOperations::ValidateAndFixInfluences ( FMeshDescription &  MeshDescription, bool &  bOutInfluenceCountLimitHit  )

static

Function will do the following steps on the MeshDescription (SkeletalMeshDescription) :

• Sort influences by weight and BoneIndex.
• Normalize influence weights.
• provide flag if InfluenceCount exceeds MAX_TOTAL_INFLUENCES
• Make sure all verts have influences set (if none exist bone 0 with weight 1)

ValidateFixComputeMeshDescriptionData()

void FSkeletalMeshOperations::ValidateFixComputeMeshDescriptionData ( FMeshDescription &  MeshDescription, const TArray< uint32 > &  FaceSmoothingMasks, int32  LODIndex, const bool  bComputeWeightedNormals, const FString &  SkeletalMeshPath  )

static

Helper function to follow behavior generated in FSkeletalMeshImportData::GetMeshDescription, just straight on FMeshDescriptions It will do the following steps:

• ConvertSmoothGroupToHardEdges
• ValidateAndFixData
• HasInvalidVertexInstanceNormalsOrTangents -> ComputeTriangleTangentsAndNormals
• (Re)BuildIndexers

---

The documentation for this class was generated from the following files:

• Engine/Source/Runtime/SkeletalMeshDescription/Public/SkeletalMeshOperations.h
• Engine/Source/Runtime/SkeletalMeshDescription/Private/SkeletalMeshOperations.cpp