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  3. FPolygroupsGenerator

FPolygroupsGenerator

[FPolygroupsGenerator](API\Plugins\DynamicMesh\FPolygroupsGenerator) generates (face/tri/poly)groups for an input mesh based on the geometry and attributes of the input mesh.

API > API/Plugins > API/Plugins/DynamicMesh

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.

   
Name FPolygroupsGenerator
Type class
Header File /Engine/Plugins/Runtime/GeometryProcessing/Source/DynamicMesh/Public/Polygroups/PolygroupsGenerator.h
Include Path #include "Polygroups/PolygroupsGenerator.h"

Syntax

class FPolygroupsGenerator

Constructors

Name Remarks Include Path Unreal Specifiers
  Polygroups/PolygroupsGenerator.h  
  Polygroups/PolygroupsGenerator.h  

Enums

Public

Name Remarks
EWeightingType Weight potions for algorithms below

Variables

Public

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

Functions

Public

Name Remarks Include Path Unreal Specifiers
Copy the computed Polygroups to the input Mesh. Polygroups/PolygroupsGenerator.h  

void CopyPolygroupsToPolygroupSet ( FPolygroupSet& Polygroups,
FDynamicMesh3& TargetMesh
)

 Copy the computed Polygroups to the given PolygroupSet and Mesh Polygroups/PolygroupsGenerator.h  
Initialize the PolygroupEdges output member by finding all the mesh edges that are on polygroup borders. Polygroups/PolygroupsGenerator.h  

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. Polygroups/PolygroupsGenerator.h  

bool FindPolygroupsFromConnectedTris ( TFunction< bool(int32 TriA, int32 TriB)> AreTrisConnected
)

 Find PolyGroups based on mesh connectivity and optionally a custom indicator function Polygroups/PolygroupsGenerator.h  

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. Polygroups/PolygroupsGenerator.h  

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). Polygroups/PolygroupsGenerator.h  

bool FindPolygroupsFromHardNormalSeams()

 Find Polygroups based on Seams in UV Overlay Polygroups/PolygroupsGenerator.h  

bool FindPolygroupsFromMaterialIDs()

 Find PolyGroups based on Material IDs i.e., connected groups of triangles with the same Material ID become a PolyGroup Polygroups/PolygroupsGenerator.h  

bool FindPolygroupsFromUVIslands ( int32 UVLayer
)

 Find Polygroups based on UV Islands, ie each UV Island becomes a Polygroup Polygroups/PolygroupsGenerator.h  

bool FindSourceMeshPolygonPolygroups ( bool bRespectUVSeams,
bool bRespectNormalSeams,
double QuadAdjacencyWeight,
double QuadMetricClamp,
int MaxSearchRounds
)

 Find Polygroups by trying to invert triangluation of a polygon mesh Polygroups/PolygroupsGenerator.h  

Protected

Name Remarks Include Path Unreal Specifiers

void GetSeamConstraintEdges ( bool bUVSeams,
bool bNormalSeams,
TSet< int32 >& ConstraintEdgesOut
) const

   Polygroups/PolygroupsGenerator.h  

void OptimizePolygroups ( TFunctionRef< bool(int32, int32)> TrisConnectedPredicate
)

   Polygroups/PolygroupsGenerator.h  

void PostProcessPolygroups ( bool bApplyMerging,
TFunctionRef< bool(int32, int32)> TrisConnectedPredicate
)

   Polygroups/PolygroupsGenerator.h  

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