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clusterConnectedFaces

Cluster connected faces

Since R2023a

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    Syntax

    [faceClusterIdx,clusterNumFaces,clusterArea] = clusterConnectedFaces(surfaceMeshIn)

    Description

    [faceClusterIdx,clusterNumFaces,clusterArea] = clusterConnectedFaces(surfaceMeshIn) clusters the connected faces in the surface mesh surfaceMeshIn, and returns the cluster index for each face faceClusterIdx, the number of connected faces in each cluster clusterNumFaces, and the surface area of each cluster clusterArea.

    example

    Examples

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    Open Live Script

    Define 12 mesh vertices in a 12-by-3 matrix vertices. Each row of vertices specifies the [x y z] coordinates of a vertex. Each vertex has a vertex ID equal to its row number in vertices.

    vertices = [1 -1  1; 
            1  1  1; 
           -1  1  1; 
           -1 -1  1; 
            1 -1 -1; 
            1  1 -1; 
           -1  1 -1; 
           -1 -1 -1; 
            2  0  0; 
            2  2  0; 
            1  0  0; 
           -1  0 -2];

    Use the vertices to define triangular mesh faces in the matrix faces. Each row of the matrix is in the form [V1 V2 V3], specifying the vertex IDs of the vertices that define the triangular face.

    faces = [6  2  1; 
         1  5  6; 
         8  4  3; 
         3  7  8; 
         6  7  3; 
         3  2  6; 
         5  1  4; 
         4  8  5; 
         4  1  2; 
         2  3  4; 
         7  6  5; 
         5  8  7; 
         9  10 11; 
         9  10 12; 
         9  11 12; 
         10 11 12];

    Create a surface mesh from the vertices and faces.

    mesh = surfaceMesh(vertices,faces);

    Cluster the connected triangular faces of the mesh.

    [faceClusterIdx,clusterNumFaces,clusterArea] = clusterConnectedFaces(mesh);

    Visualize the surface mesh.

    surfaceMeshShow(mesh,Title="Original Mesh")

    Extract the first cluster of the surface mesh.

    idx = 1:size(vertices,1);
firstFaces = faces(faceClusterIdx==1,:);
idx(unique(firstFaces))=[];
firstMesh = surfaceMesh(vertices,firstFaces);
removeVertices(firstMesh,idx)

    Visualize the first cluster of the surface mesh.

    surfaceMeshShow(firstMesh,Title="First Cluster Mesh")

    Extract the second cluster of the surface mesh.

    idx = 1:size(vertices,1);
secondFaces = faces(faceClusterIdx==2,:);
idx(unique(secondFaces))=[];
secondMesh = surfaceMesh(vertices,secondFaces);
removeVertices(secondMesh,idx)

    Visualize the second cluster of the surface mesh.

    surfaceMeshShow(secondMesh,Title="Second Cluster Mesh")

    Input Arguments

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    Input surface mesh, specified as a surfaceMesh object.

    Output Arguments

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    Cluster indices of faces, returned as a numeric vector. Each element of the vector specifies the cluster index of a face in the surface mesh. The length of the faceClusterIdx vector is equal to the number of faces in surfaceMeshIn.

    Data Types: uint64

    Number of connected faces in each cluster, returned as a numeric vector. Each element of the vector specifies the number of connected faces in a cluster. The length of the clusterNumFaces vector is equal to the number of clusters created from the connected faces of surfaceMeshIn.

    Data Types: uint64

    Surface area of clusters, returned as a numeric vector. Each element of the vector specifies the surface area of a cluster of connected faces. The length of the clusterArea vector is equal to the number of clusters created from the connected faces of surfaceMeshIn.

    Data Types: double

    Version History

    Introduced in R2023a

    See Also

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