nearestFace

Find faces nearest to specified point

Syntax

FaceID = nearestFace(g,Coords)

Description

FaceID = nearestFace(g,Coords) finds faces nearest to the point with the coordinates Coords.

Examples

Faces of 3-D Geometry Closest to Specified Points

Find faces of a block nearest to the specified points.

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. Add the points with the coordinates (0 0 0.1), (2 0.9 1), and (1.5 -1 1) to the plot.

pdegplot(gm,"FaceLabels","on","FaceAlpha",0.2)
hold on
scatter3([0 2 1.5],[0 0.9 -1],[0.1 1 1],"filled","MarkerFaceColor","g")

Find faces closest to the points with the coordinates (0 0 0.1), (2 0.9 1), and (1.5 -1 1). If several faces are equally close (within the tolerance) to the point, nearestFace returns the ID of one of the faces.

faceIDs = nearestFace(gm,[0 0 0.1; 2 0.9 1; 1.5 -1 1])

faceIDs = 1×3

     1     3     6

Faces of 2-D Geometry Closest to Specified Points

Find faces of the L-shaped membrane nearest to the specified points.

Create a model and include this geometry. The geometry of the L-shaped membrane is described in the file lshapeg.

model = createpde();
gm = geometryFromEdges(model,@lshapeg)

gm = 
  AnalyticGeometry with properties:

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

Plot the geometry with the face labels. Add the points with the coordinates (0 0), (1.1 -0.2), and (-0.5 0.5) to the plot.

pdegplot(gm,"FaceLabels","on")
hold on
scatter([0 1.1 -0.5],[0 -0.2 0.5],"filled")

Find faces closest to the points with the coordinates (0 0), (1.1 -0.2), and (-0.5 0.5). If several faces are equally close (within the tolerance) to the point, nearestFace returns the ID of one of the faces.

faceIDs = nearestFace(gm,[0 0; 1.1 -0.2; -0.5 0.5])

faceIDs = 1×3

     2     3     1

Input Arguments

g — Geometry

fegeometry object | DiscreteGeometry object | AnalyticGeometry object

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

Coords — Coordinates

N-by-2 numeric matrix | N-by-3 numeric matrix

Coordinates of the points, specified as an N-by-2 or N-by-3 numeric matrix for a 2-D or 3-D geometry, respectively. Here, N is the number of points.

Data Types: double

Output Arguments

FaceID — IDs of faces nearest to specified point

positive number | vector of positive numbers

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

Version History

Introduced in R2021a

R2023a: Finite element model

nearestFace now accepts geometries specified by fegeometry objects.