shape.Custom3D

Create custom 3-D shape from other shapes or triangulation

Since R2023b

Description

The shape.custom3D lets you create a custom shape by using other shapes or triangulation with metal and dielectric material properties. Use this custom shape along with the other shapes and the geometric operations to create a shape for the custom antenna.

Creation

Syntax

custom3d = shape.Custom3D

custom3d = shape.Custom3D(tr)

custom3d = shape.Custom3D(PropertyName=Value)

Description

custom3d = shape.Custom3D creates a custom shape.

custom3d = shape.Custom3D(tr) creates a custom shape using the triangulation data, where tr object is created using the triangulation function.

custom3d = shape.Custom3D(PropertyName=Value) sets properties using one or more name-value arguments. PropertyName is the property name and Value is the corresponding value. You can specify several name-value arguments in any order as PropertyName1=Value1, ..., PropertyNameN=ValueN. Properties that you do not specify retain their default values.

For example, custom3d = shape.Custom3D(Name="MyShape",Metal="Copper") creates a 3-D copper shape with default vertices, named "MyShape".

Properties

Name — Name of custom shape

"custom3D" (default) | string

Name of the custom shape, specified as a string.

Example: "CustomShape1"

Data Types: string

Vertices — Cartesian coordinates of polygon vertices

8-by-3 matrix (default) | N-by-3 matrix

Cartesian coordinates of the shape vertices, specified as a N-by-3 matrix in meters, where N is the number of points.

Example: [-1 0 0; -0.5 0.2 0; 0 0 0]

Data Types: double

Metal — Metal material of shape

"PEC" (default) | string

Metal material of the shape, specified as a metal name string from the Metal Catalog. To use the shape as a pure metal, set the Dielectric property to "Air". To create a metal-dielectric shape, use the addSubstrate function.

Example: "Copper"

Data Types: string

Dielectric — Dielectric material of shape

"Air" (default) | string

Dielectric material of the shape, specified as a dielectric name string from the Dielectric Catalog. To use the shape as a pure dielectric, set this property's value to a material other than "Air". In this scenario, value specified in the Metal property is ignored. To create a metal-dielectric shape, use the addSubstrate function.

Example: "Teflon"

Data Types: string

FrequencyModel — Frequency dispersion model

"Constant" (default) | "DjordjevicSarkar" | "MeanDjordjevicSarkar"

Frequency dispersion model for dielectric material, specified as a string. The default frequency model is Constant. Other supported frequency models are as below:

• Frequency independent: Constant

• Frequency dependent: DjordjevicSarkar and MeanDjordjevicSarkar

The DjordjevicSarkar model uses extrapolation techniques to predict properties of dielectric materials over a wide frequency range from a single frequency point measurement. The MeanDjordjevicSarkar model uses average value of the DjordjevicSarkar model over a frequency range of interest to predict properties of dielectric materials. Use the frequency independent model for narrow band applications. Use the frequency dependent models for wideband applications.

Example: "DjordjevicSarkar"

Data Types: string

Color — Color of shape

"y" (default) | character scalar | "Individual" | three-element real vector of RGB triplet

Color of shape, specified as either a character for color short name or a three-element real vector of RGB triplets. The default shape color is yellow. See the Types of Color Values supported by this property. When you unite two shapes of different colors, use "Individual" value to retain the colors of the original shapes in the resultant shape.

Example: "r"

Example: [0 0.447 0.741]

Data Types: double | string | char

Transparency — Transparency of shape

1 (default) | positive scalar within (0,1)

Transparency of shape, specified as a scalar in the (0,1) range, where 0 corresponds to full transparency while 1 corresponds to full opaqueness.

Example: 0.75

Data Types: double

EdgeColor — Color of shape edges

"k" (default) | character scalar | "Individual" | three-element real vector of RGB triplet

Color of shape edges, specified as either a character for color short name or a three-element real vector of RGB triplets. The default edge color is black. See the Types of Color Values supported by this property. When you unite two shapes of different edge colors, use "Individual" value to retain the edge colors of the original shapes in the resultant shape.

Example: "b"

Example: [0.4940 0.1840 0.5560]

Data Types: double | string | char

Object Functions

Boolean Operation

add	Perform Boolean unite operation on two shapes
and	Perform Boolean intersection operation on two shapes
intersect	Generate and plot intersection of two shapes
minus	Carve a shape from other shape
plus	Join two shapes
subtract	Perform Boolean subtraction operation on two shapes

Modification

addSubstrate	Create metal-dielectric shape
createHole	Create a 2-D hole on custom shape
extrude	Extrude 2-D shape on another shape
imprintShape	Imprint 2-D shape on another shape
removeFaces	Interactively select and remove 3-D shape faces

Rotation and Scaling

rotate	Rotate shape about axis by angle
rotateX	Rotate shape about x-axis by angle
rotateY	Rotate shape about y-axis by angle
rotateZ	Rotate shape about z-axis by angle
scale	Change size of shape by fixed factor
translate	Move shape to new location

Meshing and Visualization

getShapeVertices	Find shape vertices
mesh	Generate and view mesh for antennas, arrays, and custom shapes
show	Display antenna, array structures, shapes, or platform

Examples

Join Box and Custom 3-D Shape

Create and join a box and a custom 3-D shape.

b = shape.Box;
c = shape.Custom3D; 
s = plus(b,c)

s = 
  Custom3D with properties:

              Name: 'custom3D'
          Vertices: [23×3 double]
             Metal: 'PEC'
        Dielectric: 'Air'
    FrequencyModel: 'Constant'
             Color: 'Individual'
      Transparency: 'Individual'
         EdgeColor: 'Individual'

Alternatively, you can directly join shapes using the '+' operator.

b + c;

Create Custom Antenna from Horn Antenna

This example shows how to create a custom antenna from an element in the antenna catalog.

Create a default horn antenna and manually mesh it with a maximum edge length of 0.01 m.

ant = horn;
feedLoc = ant.FeedLocation;
m = mesh(ant,MaxEdgeLength=0.01);

Use triangulation to store the mesh data of this horn antenna.

p = m.Points';
t = m.Triangles';
tr = triangulation(t(:,1:4),p)

tr = 
  triangulation with properties:

              Points: [327×3 double]
    ConnectivityList: [602×4 double]

Use shape.Custom3D to generate a horn shape from triangulation data. Visualize the shape.

hornShape = shape.Custom3D(tr);
show(hornShape)

Create a box.

hole = shape.Box(Length=0.012, Width=0.004, Height=0.005);
translate(hole,[-hole.Length 0 (hole.Length/2)+hole.Height/2]);

Cut a hole in the horn geometry by subtracting the box from it. Visualize the custom shape.

hornShape = subtract(hornShape,hole);
show(hornShape)

Use customAntenna to create a custom antenna from the custom horn shape. Add feed to it and visualize the antenna.

ant = customAntenna(Shape=hornShape);
[~] = createFeed(ant,feedLoc,1);
figure
show(ant)
title("Custom Horn Antenna")

Create Custom Shape by Intersecting Shapes

This example shows how to create a custom shape using a 3-D trapezoid and sphere.

Create and view a 3-D trapezoid.

a = shape.Custom3D(Color=[0.9290 0.6940 0.1250]);
show(a)

Create and view a sphere.

b = shape.Sphere(Color=[0.9290 0.6940 0.1250]);
show(b)

Intersect the 3-D trapezoid with the sphere and view the resultant shape.

intersect(a,b);

Version History

Introduced in R2023b

R2025a: Use frequency dispersion model for dielectric material

Use frequency dispersion models to include the effect of frequency variation on the dielectric material properties of the shape. The default model is Constant meaning the dielectric material properties are constant and frequency independent. Other supported models are frequency dependent DjordjevicSarkar and MeanDjordjevicSarkar. Use the FrequencyModel property to specify the frequency model for the shape.