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> Unreal Engine API Reference > Runtime > GeometryCore > DynamicMesh > FDynamicMeshChangeTracker

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FDynamicMeshChangeTracker

[FDynamicMeshChangeTracker](API\Runtime\GeometryCore\DynamicMesh\FDynamicMeshChangeTracker) tracks changes to a FDynamicMesh and returns a [FDynamicMeshChange](API\Runtime\GeometryCore\DynamicMesh\FDynamicMeshChange) instance that represents this change and allows it to be reverted/reapplied.

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Warnings

Currently only vertices that are part of saved triangles will be stored in the emitted FMeshChange!

References

Module	GeometryCore
Header	/Engine/Source/Runtime/GeometryCore/Public/DynamicMesh/DynamicMeshChangeTracker.h
Include	#include "DynamicMesh/DynamicMeshChangeTracker.h"

Syntax

class FDynamicMeshChangeTracker

Remarks

FDynamicMeshChangeTracker tracks changes to a FDynamicMesh and returns a FDynamicMeshChange instance that represents this change and allows it to be reverted/reapplied. This is the top-level class you likely want to use to track mesh changes.

Call BeginChange() before making any changes to the mesh, then call SaveVertex() and SaveTriangle() before modifying the respective elements. Then call EndChange() to construct a FDynamicMeshChange that represents the mesh delta.

Currently only vertices that are part of saved triangles will be stored in the emitted FMeshChange!

Variables

	Name	Description
FDynamicMeshAtt...	AttribChangeTracker	Active attribute tracker, if Mesh has attribute overlays
FDynamicMeshCha...	Change	Active change that is being constructed
TBitArray	ChangedTriangles
TBitArray	ChangedVertices
int32	MaxTriangleID
int32	MaxVertexID
const FDynamicM...	Mesh
TBitArray	StartTriangles
TBitArray	StartVertices

Constructors

	Name	Description
	FDynamicMeshChangeTracker ( const FDynamicMesh3* Mesh )

Destructors

	Name	Description
	~FDynamicMeshChangeTracker()

Functions

	Name	Description
void	BeginChange()	Initialize the change-tracking process
TUniquePtr< ...	EndChange()	Construct a change object that represents the delta between the Begin and End states
void	SaveEdge ( int32 EdgeID, bool bVertices )	Save necessary information about an edge before it is modified
void	SaveTriangle ( int32 TriangleID, bool bSaveVertices )	Save necessary information about a triangle before it is modified
void	SaveTriangles ( EnumerableType TriangleIDs, bool bSaveVertices )	Save necessary information about a set of triangles before they are modified
void	SaveTrianglesAndNeighbourTris ( EnumerableType TriangleIDs, bool bSaveVertices )	Save necessary information about a set of triangles before they are modified, and also include any direct triangle neighbours
void	SaveVertex ( int32 VertexID )	Currently EndChange() only stores vertices that are part of modified triangles.
void	SaveVertexOneRingTriangles ( int32 VertexID, bool bSaveVertices )	Save necessary information about a set of triangles in one-ring of a vertex
void	SaveVertexOneRingTriangles ( EnumerableType VertexIDs, bool bSaveVertices )	Save necessary information about a set of triangles in one-rings of a set of vertices
void	SaveVertices ( EnumerableType VertexIDs )	Save necessary information about a set of vertices before they are modified
void	VerifySaveState()	Do (limited) sanity checking to make sure that the change is well-formed