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  3. FMeshPlanarSymmetry

FMeshPlanarSymmetry

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

API > API/Plugins > API/Plugins/DynamicMesh > API/Plugins/DynamicMesh/Parameterization

References

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

Syntax

class FMeshPlanarSymmetry

Remarks

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

Variables

  Type Name Description
Public variable bool bCanIgnoreDegenerateSymmetries 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.
Protected variable FVector3d CachedSymmetryAxis  
Protected variable FFrame3d SymmetryFrame  
Protected variable FDynamicMesh3 * TargetMesh  
Protected variable TArray< FSymmetryVertex > Vertices List of vertices, size == TargetMesh.MaxVertexID()

Functions

  Type Name Description
Public function Const void

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

 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)
Public function Const void

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

 Given the pairing (SourceVertexROI, SourceVertexPositions), compute the symmetry-constrained vertex positions for MirrorVertexROI and store in MirrorVertexPositionsOut.
Public function 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
Public function void Update all the symmetry vertex positions based on their Positive-side pair vertex.
Public function Const FVector3d

GetMirroredAxis ( const FVector3d& Axis
)

  
Public function Const FQuaterniond

GetMirroredOrientation ( const FQuaterniond& Orientation
)

  
Public function Const FVector3d

GetMirroredPosition ( const FVector3d& Position
)

  
Public function Const void

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

 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.
Public function Const FFrame3d  
Public function 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
Public function 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
Protected function void

UpdatePlaneVertex ( int32 VertexID
)

  
Protected function void

UpdateSourceVertex ( int32 VertexID
)

  

Classes

  Type Name Description
Protected struct FSymmetryVertex    

Constants

Name Description
MatchFeaturesTolerance Note for features we specify a direct tolerance instead of a factor, as features are already in their own re-scaled space.
MatchVertexToleranceFactor  
OnPlaneToleranceFactor Tolerances used for matching / hashing in symmetry-findingPoint must be within this distance from the symmetry plane to be considered "on" the plane.
VertexHashCellSizeFactor 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.

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