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  3. FLocalPlanarSimplify

FLocalPlanarSimplify

Class to support local planar simplification, to reduce excess edges created by plane cuts, edge loop insertions, and similar operations (Note a custom version of this logic also exists on the [FMeshBoolean](API\Runtime\GeometryCore\Operations\FMeshBoolean) class)

API > API/Runtime > API/Runtime/GeometryCore > API/Runtime/GeometryCore/Operations

References

   
Module GeometryCore
Header /Engine/Source/Runtime/GeometryCore/Public/Operations/LocalPlanarSimplify.h
Include #include "Operations/LocalPlanarSimplify.h"

Syntax

class FLocalPlanarSimplify

Remarks

Class to support local planar simplification, to reduce excess edges created by plane cuts, edge loop insertions, and similar operations (Note a custom version of this logic also exists on the FMeshBoolean class)

Variables

  Type Name Description
Public variable bool bPreserveOverlayUVs Prevent simplification from distorting overlay UVs
Public variable bool bPreserveTriangleGroups Prevent simplification from distorting triangle groups
Public variable bool bPreserveVertexNormals Prevent simplification from distorting vertex normals
Public variable bool bPreserveVertexUVs Prevent simplification from distorting vertex UVs
Public variable float NormalDistortTolerance When preserving normals, sets maximum allowed change in normals from collapsing an edge, measured at the removed vertex in degrees
Public variable double SimplificationAngleTolerance Degrees of deviation from coplanar that we will still simplify
Public variable double TryToImproveTriQualityThreshold If triangle quality (aspect ratio) is worse than this threshold, only simplify in ways that improve quality.
Public variable float UVDistortTolerance When preserving UVs, sets maximum allowed change in UV coordinates from collapsing an edge, measured at the removed vertex

Functions

  Type Name Description
Public function Static bool

CollapseWouldChangeShapeOrUVs ( const FDynamicMesh3& Mesh,
const TSet< int >& PathEdgeSet,
double DotTolerance,
int SourceEID,
int32 RemoveV,
const FVector3d& RemoveVPos,
int32 KeepV,
const FVector3d& KeepVPos,
const FVector3d& EdgeDir,
bool bPreserveTriangleGroups,
bool bPreserveUVsForMesh,
bool bPreserveVertexUVs,
bool bPreserveOverlayUVs,
float UVToleranceSq,
bool bPreserveVertexNormals,
float NormalEqualCosThreshold
)

 Test if a given edge collapse would change the mesh shape, mesh triangle group shape, or UVs unacceptably
Public function Static bool

CollapseWouldHurtTriangleQuality ( const FDynamicMesh3& Mesh,
const FVector3d& RemoveVNormal,
int32 RemoveV,
const FVector3d& RemoveVPos,
int32 KeepV,
const FVector3d& KeepVPos,
double TryToImproveTriQualityThreshold,
bool bHasMultipleNormals
)

 Test if a given edge collapse would cause a triangle flip or other unacceptable decrease in mesh quality Specialized for collapsing at flat triangles Test if a given edge collapse would cause a triangle flip or other unacceptable decrease in mesh quality
Public function Static bool

IsDevelopableAlongEdge ( const FDynamicMesh3& Mesh,
int EID,
int VID,
double DotTolerance,
FVector3d& NormalA,
bool& bIsFlat
)

 Test if the triangles connected to a vertex could be flattened by folding along the given edge
Public function Static bool

IsFlat ( const FDynamicMesh3& Mesh,
int VID,
double DotTolerance,
FVector3d& OutFirstNormal
)

 The below helper functions are used by SimplifyAlongEdges, but also the similar customized versions of the same algorithm in FMeshBoolean and FMeshSelfUnion as well Test if the triangles connected to a vertex are all coplanar
Public function Const void

SimplifyAlongEdges ( FDynamicMesh3& Mesh,
TSet< int32 >& InOutEdges,
TUniqueFunction< void(const DynamicMeshInfo::FEdgeCollapseInfo&)> ProcessCollapse
)

 Simplify Mesh along the given edges, and update the edge set accordingly

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