faceEdges

R2026b

Find edges belonging to specified faces

Syntax

EdgeID = faceEdges(g,RegionID)

EdgeID = faceEdges(g,RegionID,FilterType)

Description

EdgeID = faceEdges(g,RegionID) finds edges belonging to the faces with ID numbers listed in RegionID.

EdgeID = faceEdges(g,RegionID,FilterType) returns internal, external, or all edges belonging to the faces with ID numbers listed in RegionID. This syntax is valid for 3-D geometries only.

Examples

Edges Belonging to Specified Faces of 3-D Geometry

Find edges belonging to the top and bottom faces of a block.

Create a block geometry.

gm = multicuboid(3,2,1)

gm = 
  DiscreteGeometry with properties:

       NumCells: 1
       NumFaces: 6
       NumEdges: 12
    NumVertices: 8
       Vertices: [8×3 double]

Plot the geometry with the face labels.

pdegplot(gm,FaceLabels="on",FaceAlpha=0.2)

Find edges belonging to faces 1 and 2.

edgeIDs = faceEdges(gm,[1 2])

edgeIDs = 1×8

     1     2     3     4     5     6     7     8

Plot the geometry with the edge labels.

figure
pdegplot(gm,EdgeLabels="on",FaceAlpha=0.2)

Edges Belonging to Specified Faces of 2-D Geometry

Find edges belonging to two faces of the L-shaped membrane.

Create a geometry representing the L-shaped membrane by using lshapeg.

gm = fegeometry(@lshapeg)

gm = 
  fegeometry with properties:

        NumCells: 0
        NumFaces: 3
        NumEdges: 10
     NumVertices: 8
        Vertices: [8×2 double]
    FeatureAngle: []
            Mesh: []

Plot the geometry with the face labels.

pdegplot(gm,FaceLabels="on")

Find edges belonging to faces 1 and 2.

edgeIDs = faceEdges(gm,[1 2])

edgeIDs = 1×8

     1     2     3     6     7     8     9    10

Plot the geometry with the edge labels.

pdegplot(gm,EdgeLabels="on")

Edges Belonging to Internal and External Faces

Find edges belonging to the side face of the inner cuboid in a geometry consisting of two nested cuboids.

Create a geometry that consists of two nested cuboids of the same height.

gm = multicuboid([2 5],[4 10],3)

gm = 
  DiscreteGeometry with properties:

       NumCells: 2
       NumFaces: 12
       NumEdges: 24
    NumVertices: 16
       Vertices: [16×3 double]

Plot the geometry with the face labels.

pdegplot(gm,FaceLabels="on",FaceAlpha=0.2)

Find all edges belonging to the side face of the inner cuboid.

edgeIDs = faceEdges(gm,6)

edgeIDs = 1×4

     1     5    10    12

From all edges belonging to that face, return the edges belonging to only the internal faces. Internal faces are faces shared between multiple cells.

edgeIDs = faceEdges(gm,6,"internal")

edgeIDs = 1×2

    10    12

From all edges belonging to that face, return the edges belonging to the external faces.

edgeIDs = faceEdges(gm,6,"external")

edgeIDs = 1×2

     1     5

Plot the geometry with the edge labels.

pdegplot(gm,EdgeLabels="on",FaceAlpha=0.2)

Input Arguments

g — Geometry

fegeometry object | DiscreteGeometry object | AnalyticGeometry object

Geometry, specified as an fegeometry object, a DiscreteGeometry object, or an AnalyticGeometry object.

RegionID — Face ID

positive number | vector of positive numbers

Face ID, specified as a positive number or a vector of positive numbers. Each number represents a face ID.

FilterType — Type of edges to return

"all" (default) | "internal" | "external"

Type of edges to return, specified as "internal", "external", or "all". Depending on this argument, faceEdges returns these types of faces for a 3-D geometry:

• "internal" — Edges belonging to only internal faces. Internal faces are faces shared between multiple cells.

• "external" — Edges belonging to only external faces. External faces are faces not shared between multiple cells.

• "all" — All edges belonging to the specified cells.

Output Arguments

EdgeID — IDs of edges belonging to specified faces

positive number | vector of positive numbers

IDs of edges belonging to the specified faces, returned as a positive number or a vector of positive numbers.

Version History

Introduced in R2021a

R2023a: Finite element model

faceEdges now accepts geometries specified by fegeometry objects.