addVertex

Add a vertex on a geometry boundary

Syntax

VertexID = addVertex(g,'Coordinates',Coords)

Description

VertexID = 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.

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 PDE model.

model = createpde();

Import the geometry.

g = importGeometry(model,'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.

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

VertexID = 9

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]);
VertexIDs = addVertex(g,'Coordinates',V)

VertexIDs = 3×1

    10
    11
    12

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.

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

VertexID = 5

Input Arguments

g — Geometry

DiscreteGeometry object

Geometry, specified as 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

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. See AnalyticGeometry Properties.