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  3. FMeshPlanarSymmetry

FMeshPlanarSymmetry

[FMeshPlanarSymmetry](API\Plugins\DynamicMesh\FMeshPlanarSymmetry) detects pairwise symmetry relationships between vertices in a mesh, given a symmetry frame.

API > API/Plugins > API/Plugins/DynamicMesh

FMeshPlanarSymmetry detects pairwise symmetry relationships between vertices in a mesh, given a symmetry frame. Once those relationships are known, symmetry can be re-enforced after mesh edits.

Vertices within a tolerance band of the symmetry plane do not have a mirror and are considered "on plane" and will be snapped to the symmetry plane when enforcing symmetry after edits.

The Symmetry Plane is specified by a Frame3d where the XY axes define the plane and the Z axis is the plane normal. So references to "Positive" side below are relative to that Z axis/plane

   
Name FMeshPlanarSymmetry
Type class
Header File /Engine/Plugins/Runtime/GeometryProcessing/Source/DynamicMesh/Public/Parameterization/MeshPlanarSymmetry.h
Include Path #include "Parameterization/MeshPlanarSymmetry.h"

Syntax

class FMeshPlanarSymmetry

Structs

Name Remarks
FSymmetryVertex  

Constants

Name Type Remarks Include Path
MatchFeaturesTolerance double Note for features we specify a direct tolerance instead of a factor, as features are already in their own re-scaled space. Parameterization/MeshPlanarSymmetry.h
MatchVertexToleranceFactor double   Parameterization/MeshPlanarSymmetry.h
OnPlaneToleranceFactor double Tolerances used for matching / hashing in symmetry-finding Point must be within this distance from the symmetry plane to be considered "on" the plane. Parameterization/MeshPlanarSymmetry.h
VertexHashCellSizeFactor double Note performance of vertex hashing is much better when VertexHashCellSize is large enough that most hash lookups only need to look at a single cell. Parameterization/MeshPlanarSymmetry.h

Variables

Public

Name Type Remarks Include Path Unreal Specifiers
bCanIgnoreDegenerateSymmetries bool If true, symmetry-finding can return false if it detects a symmetry where all points are on the symmetry plane, rather than attempt to fit a symmetry plane in that case. Parameterization/MeshPlanarSymmetry.h  

Protected

Name Type Remarks Include Path Unreal Specifiers
ErrorScale double Internal error scale; for large meshes, we need larger tolerances because floating point values will be less accurate. Parameterization/MeshPlanarSymmetry.h  

Functions

Public

Name Remarks Include Path Unreal Specifiers

void ApplySymmetryPlaneConstraints ( const TArray< int >& VertexIndices,
TArray< FVector3d >& VertexPositionsInOut
) const

 For any vertices in VertexIndices that are on-plane, take the position in VertexPositionsInOut, apply the on-plane constraint, and return the constrained position in VertexPositionsInOut (ie VertexPositionsInOut is updated to new positions) Parameterization/MeshPlanarSymmetry.h  

void ComputeSymmetryConstrainedPositions ( const TArray< int >& SourceVertexROI,
const TArray< int >& MirrorVertexROI,
const TArray< FVector3d >& SourceVertexPositions,
TArray< FVector3d >& MirrorVertexPositionsOut
) const

 Given the pairing (SourceVertexROI, SourceVertexPositions), compute the symmetry-constrained vertex positions for MirrorVertexROI and store in MirrorVertexPositionsOut. Parameterization/MeshPlanarSymmetry.h  

bool FindPlaneAndInitialize ( FDynamicMesh3* Mesh,
const FAxisAlignedBox3d& Bounds,
FFrame3d& SymmetryFrameOut,
TArrayView< const FVector3d > PreferredNormals
)

 Given a Mesh and its bounding box, find a Symmetry Plane/Frame and detect any pairs of vertices with planar/mirror-symmetry relationships, as well as "on plane" vertices Parameterization/MeshPlanarSymmetry.h  
Update all the symmetry vertex positions based on their Positive-side pair vertex. Parameterization/MeshPlanarSymmetry.h  

FVector3d GetMirroredAxis ( const FVector3d& Axis
) const

   Parameterization/MeshPlanarSymmetry.h  

FQuaterniond GetMirroredOrientation ( const FQuaterniond& Orientation
) const

   Parameterization/MeshPlanarSymmetry.h  

FVector3d GetMirroredPosition ( const FVector3d& Position
) const

   Parameterization/MeshPlanarSymmetry.h  

void GetMirrorVertexROI ( const TArray< int >& VertexROI,
TArray< int >& MirrorVertexROIOut,
bool bForceSameSizeWithGaps
) const

 The set of functions below are intended to be used together in situations like 3D sculpting where we want to apply symmetry constraints within a "brush region of interest (ROI)" See UMeshVertexSculptTool for example usage Computes list of vertices that are mirror-constrained to vertices in VertexROI. Parameterization/MeshPlanarSymmetry.h  

FFrame3d GetPositiveSideFrame ( FFrame3d FromFrame
) const

   Parameterization/MeshPlanarSymmetry.h  

bool Initialize ( FDynamicMesh3* Mesh,
FDynamicMeshAABBTree3* Spatial,
FFrame3d SymmetryFrameIn
)

 Given a Mesh, an AABBTree, and a Symmetry Plane/Frame, detect any pairs of vertices with planar/mirror-symmetry relationships, as well as "on plane" vertices Parameterization/MeshPlanarSymmetry.h  

bool Initialize ( FDynamicMesh3* Mesh,
const FAxisAlignedBox3d& Bounds,
FFrame3d SymmetryFrameIn
)

 Given a Mesh and its bounding box, and a Symmetry Plane/Frame, detect any pairs of vertices with planar/mirror-symmetry relationships, as well as "on plane" vertices Parameterization/MeshPlanarSymmetry.h  

bool ValidateSymmetry ( const FDynamicMesh3& TestMesh
) const

   Parameterization/MeshPlanarSymmetry.h  

bool ValidateSymmetry ( const FDynamicMesh3& TestMesh,
TConstArrayView< int32 > VertexROI
) const

   Parameterization/MeshPlanarSymmetry.h  

Protected

Name Remarks Include Path Unreal Specifiers

void UpdatePlaneVertex ( int32 VertexID
)

   Parameterization/MeshPlanarSymmetry.h  

void UpdateSourceVertex ( int32 VertexID
)

   Parameterization/MeshPlanarSymmetry.h  

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