Create meshes on patch objects

Is it possible to create meshes on patch objects? Or divide a patch object in smaller pieces?

Answer 1

[Gautam]

Hello @Gozde Basara

MATLAB doesn't have a built-in function to divide a patch object in smaller pieces, but you can implement a custom function to subdivide the faces of a patch object. This typically involves splitting each face into smaller faces.

Here's a sample code you can refer to

% Define a simple triangular patch
vertices = [0 0 0; 1 0 0; 0 1 0];
faces = [1 2 3];

% Create the patch object
figure;
p = patch('Vertices', vertices, 'Faces', faces, 'FaceColor', 'cyan');

% Subdivide the patch
[newVertices, newFaces] = subdivide(vertices, faces);

% Visualize the refined mesh
hold on;
patch('Vertices', newVertices, 'Faces', newFaces, 'FaceColor', 'none', 'EdgeColor', 'black');
axis equal;

% Function to subdivide each triangle into smaller triangles
function [newVertices, newFaces] = subdivide(vertices, faces)
    newVertices = vertices;
    newFaces = [];
    for i = 1:size(faces, 1)
        % Get the vertices of the current face
        v1 = vertices(faces(i, 1), :);
        v2 = vertices(faces(i, 2), :);
        v3 = vertices(faces(i, 3), :);
        
        % Calculate midpoints
        m12 = (v1 + v2) / 2;
        m23 = (v2 + v3) / 2;
        m31 = (v3 + v1) / 2;
        
        % Add new vertices
        newVertices = [newVertices; m12; m23; m31];
        idx = size(newVertices, 1) - 2:size(newVertices, 1);
        
        % Create new faces
        newFaces = [newFaces;
                    faces(i, 1), idx(1), idx(3);
                    idx(1), faces(i, 2), idx(2);
                    idx(3), idx(2), faces(i, 3);
                    idx(1), idx(2), idx(3)];
    end
end