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FDeformableEdgePath

Given a single path initially defined by edges on a FDynamicMesh (the SurfaceMesh), this class uses an intrinsic mesh with the same vertex set to minimize the length of the path on the surface mesh.

API > API/Plugins > API/Plugins/DynamicMesh

Given a single path initially defined by edges on a FDynamicMesh (the SurfaceMesh), this class uses an intrinsic mesh with the same vertex set to minimize the length of the path on the surface mesh. This is done iteratively by a succession of local path deformations comprised of (local) intrisic edge flips and path re-routing, each deformation locally reduces the path length. The resulting path is comprised of intrinsic mesh edges.

This is an implementation of the ideas in "You Can Find Geodesic Paths in Triangle Meshes by Just Flipping Edges" by Nicholas Sharp and Keenan Crane ACM Trans. Graph. Vol. 39, No. 6, 2020

The original path is constructed as a sequence of mesh edges relative to the SurfaceMesh ( the FDynamicMesh3 ), these edges are encoded with path direction as FDirectedSegments. Note: The current implementation does not support closed paths or multiple paths.

   
Name FDeformableEdgePath
Type class
Header File /Engine/Plugins/Runtime/GeometryProcessing/Source/DynamicMesh/Public/Operations/GeodesicPath.h
Include Path #include "Operations/GeodesicPath.h"

Syntax

class FDeformableEdgePath

Constructors

Name Remarks Include Path Unreal Specifiers
Only allow construction from a path and mesh. Operations/GeodesicPath.h  
  Operations/GeodesicPath.h  

FDeformableEdgePath ( const FDynamicMesh3& SurfaceMeshIn,
const TArray< FEdgePath::FDirectedSegment >& OriginalPathAsDirectedSegments
)

 Constructor assumes the directed segments are ordered from tail (at index 0) to head Operations/GeodesicPath.h  

Destructors

Name Remarks Include Path Unreal Specifiers

virtual ~FDeformableEdgePath()

   Operations/GeodesicPath.h  

Structs

Name Remarks
FEdgePathDeformationInfo Information gathered during minimization
FPathJoint  

Enums

Protected

Name Remarks
ESide  

Typedefs

Name Type Remarks Include Path
FSurfacePoint IntrinsicCorrespondenceUtils::FSurfacePoint Struct that references a point on a mesh, by vertex, by edge-crossing, or barycentric coords Operations/GeodesicPath.h
IntrinsicMeshType FIntrinsicEdgeFlipMesh   Operations/GeodesicPath.h

Constants

Name Type Remarks Include Path
InvalidID int   Operations/GeodesicPath.h

Functions

Public

Name Remarks Include Path Unreal Specifiers

TArray< FSurfacePoint > AsSurfacePoints ( double CoalesceThreshold
) const

   Operations/GeodesicPath.h  

const FEdgePath & GetEdgePath()

   Operations/GeodesicPath.h  

const FIntrinsicEdgeFlipMesh & GetIntrinsicMesh()

   Operations/GeodesicPath.h  

double GetPathLength()

   Operations/GeodesicPath.h  

virtual void Minimize ( FEdgePathDeformationInfo& DeformedPathInfo,
const int32 MaxNumIterations
)

 Minimize the deformable edge path with respect to the total path length. Operations/GeodesicPath.h  

Protected

Name Remarks Include Path Unreal Specifiers

void ComputeWedgeAngles ( int32 IncomingEID,
int32 OutgoingEID,
int32 CenterVID,
double& LeftSideAngle,
double& RightSideAngle
) const

 Compute the two angles formed at the vertex CenterVID by the two wedges formed by splitting the local one-ring by local path specified as incoming and outgoing edges. Operations/GeodesicPath.h  

bool DeformJoint ( const int32 IncomingEID,
const int32 OutgoingEID,
int32 JointVID,
TArray< FEdgePath::FDirectedSegment >& DeformedPath,
const bool bClockwise
)

 Edge flip the adjacent edges to the JointVID and collect the DeformedPath that can be used to replace the local incoming and outgoing edge path Operations/GeodesicPath.h  

void DeformJoint ( FPathJoint& PathJoint
)

 Replace the specified two connected edge segments (FPathJoint) in the main path with a new sub-path that connects the same end points. Operations/GeodesicPath.h  

bool IsJointFlexible ( const FPathJoint& PathJoint
) const

   Operations/GeodesicPath.h  

bool OuterArcFlipEdges ( int32 StartEID,
int32 EndEID,
int32 CenterVID,
bool bClockwise
)

 Traveling either CCW or CW around vertex CenterVID, from edge StartEID to edge EndEID, flip edges adjacent to CVID. Operations/GeodesicPath.h  

void RemoveSegment ( int32 SID
)

 Remove specified segment from the linked-list path and clean up joint-related data for the joint that ends with this segment. Operations/GeodesicPath.h  

void ReplaceJointWithPath ( const FPathJoint PathJoint,
const TArray< FEdgePath::FDirectedSegment >& PathAsDirectedEdges
)

 Splice in a path to replace the joint and update the joint angle queue. Operations/GeodesicPath.h  

int32 SegmentHeadVID ( int32 SID
) const

   Operations/GeodesicPath.h  

int32 SegmentTailVID ( int32 SID
) const

   Operations/GeodesicPath.h  

void UpdateJointAndQueue ( int32 OutgoingSegmentID
)

 Compute data associated with the joint formed by the specified segment (outgoing), and the preceding segment (incoming) in the path. Operations/GeodesicPath.h  

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