FGroupTopologyDeformer | Unreal Engine 5.2 Documentation

API > API/Plugins > API/Plugins/DynamicMesh > API/Plugins/DynamicMesh/Operations

References


Module	DynamicMesh
Header	/Engine/Plugins/Runtime/GeometryProcessing/Source/DynamicMesh/Public/Operations/GroupTopologyDeformer.h
Include	#include "Operations/GroupTopologyDeformer.h"

Syntax

class FGroupTopologyDeformer

Remarks

FGroupTopologyDeformer supports deforming a Mesh based on an overlaid FGroupTopology. First the client defines a set of "Handle" elements (Faces/Corners/Edges) using SetActiveHandleX(). The client will provide new vertex positions for the vertices of these elements via the HandleVertexDeformFunc argument to UpdateSolution(). Once the Handle vertices have been updated, the deformer solves for updated vertex positions in the GroupTopology Faces that are adjacent to the handles. This region is referred to as the "ROI" (Region-of-Interest)

The default deformation is to first solve for the updated edges, and then solve for updated faces. This is done via linear encoding of the edge and face vertices relative to their boundaries (edge boundary is endpoint corners, face boundary is edges).

Various functions can be overrided to customize behavior.

Variables

	Type	Name	Description
	TArray< FEdgeEncoding >	EdgeEncodings
	TSet< int >	FaceBoundaryVertsTemp
	TArray< FFaceEncoding >	FaceEncodings
	TSet< int >	FaceVertsTemp
	TSet< int >	FixedBoundaryVertices
	TSet< int >	HandleBoundaryVertices
	TSet< int >	HandleVertices
	FVertexPositionCache	InitialPositions
	const FDynamicMesh3 *	Mesh
	TSet< int >	ModifiedOverlayNormals
	TSet< int >	ModifiedVertices
	TArray< FROIEdge >	ROIEdges
	TSet< int >	ROIEdgeVertices
	TArray< FROIFace >	ROIFaces
	const FGroupTopology *	Topology

Destructors

	Type	Name	Description
		~FGroupTopologyDeformer ()

Functions

Type	Name	Description
void	CalculateROI ( const TArray< int >& HandleGroups, const TArray< int >& ROIGroups )	Populate the internal ROI data structures based on the given HandleGroups and ROIGroups.
void	ClearSolution ( FDynamicMesh3* TargetMesh )	Restore the Handle and ROI vertex positions to their initial state
void	ComputeEncoding ()	Precompute the representation of the ROI vertices at the initial positions.
void	EnumerateROIEdges ( TFunctionRef< void(const FEdgeSpan&EdgeSpan)> EdgeSpanFunc )	Call EdgeSpanFunc for every group FEdgeSpan in the modified-area ROI that will be modified by the solver (does not include edges that are encompassed by the Handle)
const TSet< int > &	GetHandleVertices ()
const FDynamicMesh3 *	GetMesh ()
const TSet< int > &	GetModifiedOverlayNormals ()
const TSet< int > &	GetModifiedVertices ()
const FGroupTopology *	GetTopology ()
void	Initialize ( const FDynamicMesh3* Mesh, const FGroupTopology* Topology )	Set the Mesh and Topology to use for the deformation
void	Reset ()	These are functions that subclasses may wish to overridereset all internal data structures, eg when changing handle
void	SaveInitialPositions ()	Save the positions of all vertices that will be modified
void	SetActiveHandleCorners ( const TArray< int >& TopologyCornerIDs )	Set the active handle to the given Corners
void	SetActiveHandleEdges ( const TArray< int >& TopologyEdgeIDs )	Set the active handle to the given Edges
void	SetActiveHandleFaces ( const TArray< int >& FaceGroupIDs )	Handle setup/configuraiton Set the active handle to the given Faces
void	SetActiveHandleFromSelection ( const FGeometrySelection& Selection )	Set the active handle from GeometrySelection
void	UpdateSolution ( FDynamicMesh3* TargetMesh, const TFunction< FVector3d(FDynamicMesh3*Mesh, int)>& HandleVertexDeformFunc )	Solving Update TargetMesh by first calling HandleVertexDeformFunc() to get new handle vertex positions, then solving for new ROI vertex positions.