how to ordered boundary points

[ParvGuptaSpCT]

Hello devs!

Does MeshLib provide a way to reorganize the boundary points?
I have a mesh with an open boundary, and I extracted the mesh's boundary vertices. I want to make a tube around the boundary using a few equidistant points on the boundary, however the boundary points are in a random order. Is there a way to determine the proper sequence of the boundary points?

boundaryVerts = segmentMesh.topology.findBoundaryVerts()
boundaryVertsList = list()
     if(boundaryVerts.count):
          for v in boundaryVerts:
          coord = segmentMesh.points.vec[v.get()]
          boundaryVertsList.append([coord.x, coord.y, coord.z])

PS: my mesh is a segmented mesh.

Thanks
Parv

[Grantim]

Hello!

You are probably looking for this function:

MeshLib/source/MRMesh/MRRegionBoundary.h

Lines 21 to 25 in 2d018ec

	/// returns all region boundary loops;
	/// every loop has region faces on the left, and not-region faces or holes on the right
	[[nodiscard]] MRMESH_API std::vector<EdgeLoop> findLeftBoundary( const MeshTopology & topology, const FaceBitSet * region = nullptr );
	[[nodiscard]] inline std::vector<EdgeLoop> findLeftBoundary( const MeshTopology & topology, const FaceBitSet & region )
	{ return findLeftBoundary( topology, &region ); }

You can use mesh.topology.org( edgeLoops[loopId][eId] ) to origin vertex of each boundary edge.

[ParvGuptaSpCT]

Hello @Grantim !!
can you please provide an example?
PS: I want to save the point information as a json with the correct order of points

[Grantim]

Sure, it should looks somehow like this:

boundaryLoops = mm.findRightBoundary( segmentMesh.topology )
for loop in boundaryLoops:
    print( "--NEW LOOP--" )
    for e in loop:
        orgV = segmentMesh.topology.org( e )
        orgPos =  segmentMesh.orgPnt( e )
        print( orgV, orgPos.x, orgPos.y, orgPos.z )