FPolygroupsGenerator | Unreal Engine 5.5 Documentation

API > API/Plugins > API/Plugins/DynamicMesh > API/Plugins/DynamicMesh/Polygroups

References


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

Syntax

class FPolygroupsGenerator

Remarks

FPolygroupsGenerator generates (face/tri/poly)groups for an input mesh based on the geometry and attributes of the input mesh. The various FindPolygroupsFromX() are the driving functions, each performs the full computation.

Variables

Type	Name	Description
bool	bApplyPostProcessing	If true, then groups will be post-processed to optimize them, based on parmeters below
bool	bCopyToMesh	If true, after groups are computed they will be copied to the output mesh
TArray< TArray< int > >	FoundPolygroups	Lists of triangle IDs, each list defines a polygroup/polygon
int32	InitialGroupID	Start at this GroupID when assigning new groups
FDynamicMesh3 *	Mesh	Source mesh
int32	MinGroupSize	If > 1, groups with a triangle count smaller than this will be merged with a neighbouring group
TArray< int >	PolygroupEdges	List of edge IDs of mesh edges that are on polygroup borders

Constructors

	Type	Name	Description
		FPolygroupsGenerator ()
		FPolygroupsGenerator ( FDynamicMesh3* MeshIn )

Functions

Type	Name	Description
void	CopyPolygroupsToMesh ()	Copy the computed Polygroups to the input Mesh.
void	CopyPolygroupsToPolygroupSet ( FPolygroupSet& Polygroups, FDynamicMesh3& TargetMesh )	Copy the computed Polygroups to the given PolygroupSet and Mesh
bool	FindPolygroupEdges ()	Initialize the PolygroupEdges output member by finding all the mesh edges that are on polygroup borders.
bool	FindPolygroupsFromAreaDensityPointSampling ( int32 NumPoints, EWeightingType WeightingType, FVector3d WeightingCoeffs, FPolygroupSet* StartingGroups )	Similar to the technique used in FindPolygroupsFromFurthestPointSampling, except this algorithm attempts to select sample points in connected mesh regions based on the rough area of each region, granting more initial points to larger regions and fewer points to smaller regions, minium of one.
bool	FindPolygroupsFromConnectedTris ()	Find Polygroups based on mesh connectivity, ie each connected-component becomes a Polygroup
bool	FindPolygroupsFromFaceNormals ( double OneMinusCosAngleTolerance, bool bRespectUVSeams, bool bRespectNormalSeams, bool bUseAveragePolygroupNormals )	Find Polygroups by randomly picking initial seed triangles and then flood-filling outwards, stopping when the opening angle at an edge is larger than the angle defined by the OneMinusCosAngleTolerance.
bool	FindPolygroupsFromFurthestPointSampling ( int32 NumPoints, EWeightingType WeightingType, FVector3d WeightingCoeffs, FPolygroupSet* StartingGroups )	Incrementally compute approximate-geodesic-based furthest-point sampling of the mesh until NumPoints samples have been found, then compute local geodesic patches (eg approximate surface voronoi diagaram).
bool	FindPolygroupsFromHardNormalSeams ()	Find Polygroups based on Seams in UV Overlay
bool	FindPolygroupsFromUVIslands ( int32 UVLayer )	Find Polygroups based on UV Islands, ie each UV Island becomes a Polygroup
bool	FindSourceMeshPolygonPolygroups ( bool bRespectUVSeams, bool bRespectNormalSeams, double QuadAdjacencyWeight, double QuadMetricClamp, int MaxSearchRounds )	Find Polygroups by trying to invert triangluation of a polygon mesh
void	GetSeamConstraintEdges ( bool bUVSeams, bool bNormalSeams, TSet< int32 >& ConstraintEdgesOut )
void	OptimizePolygroups ( TFunctionRef< bool(int32, int32)> TrisConnectedPredicate )
void	PostProcessPolygroups ( bool bApplyMerging, TFunctionRef< bool(int32, int32)> TrisConnectedPredicate )

Enums

	Type	Name	Description
	EWeightingType	Weight potions for algorithms below

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