addVertex

Add vertex on geometry boundary

Syntax

h = addVertex(g,Coordinates=Coords)

[h,VertexID] = addVertex(g,Coordinates=Coords)

Description

h = addVertex(g,Coordinates=Coords) adds a new isolated vertex at the point with coordinates Coords to a boundary of the geometry g. To add several vertices simultaneously, specify Coords as an N-by-2 matrix for a 2-D geometry or an N-by-3 matrix for a 3-D geometry. Here, N is the number of new points.

If a point with the specified coordinates is slightly offset (within an internally specified tolerance) from a geometry boundary, addVertex approximates it to a point on the boundary. If a vertex already exists at the specified location, addVertex returns the ID of the existing vertex instead of creating one.

[h,VertexID] = addVertex(g,Coordinates=Coords) also returns a row vector containing vertex IDs including the added vertices.

Examples

Add Vertices on Edge of Block

Use addVertex to add a single vertex and multiple vertices on a side of a block geometry.

Create a block geometry.

g = fegeometry("Block.stl");

Plot the geometry and display the vertex labels.

pdegplot(g,VertexLabels="on",FaceAlpha=0.5)

Add a vertex on the edge of a block.

g = addVertex(g,Coordinates=[20 0 50]);

Plot the geometry and display the vertex labels.

pdegplot(g,VertexLabels="on",FaceAlpha=0.5)

Add three more vertices on the same edge of the block.

V = ([40 0 50; 60 0 50; 80 0 50]);
g = addVertex(g,Coordinates=V);

Plot the geometry and display the vertex labels.

pdegplot(g,VertexLabels="on",FaceAlpha=0.5)

Add a vertex at the corner of the block. Since there is already a vertex at the corner, addVertex does not create a new vertex, but returns the ID of the existing vertex.

[g,VertexID] = addVertex(g,Coordinates=[100 0 50])

g = 
  fegeometry with properties:

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

VertexID = 
5

Input Arguments

g — Geometry

fegeometry object | DiscreteGeometry object

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

Coords — Coordinates of new vertex

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

Coordinates of a new vertex, 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 new vertices.

Example: "Coordinates",[0 0 1]

Data Types: double

Output Arguments

h — Resulting geometry

fegeometry object | handle

• If the original geometry g is an fegeometry object, then h is a new fegeometry object representing the modified geometry. The original geometry g remains unchanged.

• If the original geometry g is a DiscreteGeometry object, then h is a handle to the modified object g.

VertexID — Vertex ID

row vector

Vertex ID, returned as a row vector of positive numbers. Each number represents a vertex ID. When you add a new vertex to a geometry with N vertices, the ID of the added vertex is N + 1. If a vertex already exists at the specified location, addVertex returns the ID of the existing vertex.

Limitations

• addVertex does not work with AnalyticGeometry objects.

Version History

Introduced in R2019b

R2023a: Finite element model

addVertex now accepts geometries specified by fegeometry objects.