Hi,
According to my understanding you wanted to generate 3d rectangular with cross member mesh and automatically get the connectivity matrix.
To generate a 3D rectangular mesh with cross members, you can use the generateMesh function in MATLAB. This function can generate a mesh based on a geometry description, which can be created using the cuboidGeometry function in the Partial Differential Equation Toolbox.
Here's an example MATLAB code that generates a 3D rectangular mesh with cross members:
% Define the dimensions of the rectangular mesh
L = 2; % length
W = 1; % width
H = 1; % height
% Create a cuboid geometry description
g = cuboidGeometry(L, W, H);
% Define the cross member dimensions
M = 0.1; % thickness
N = 0.5; % width
% Create the cross member geometry description
g2 = extrudeShape([0, M, 0; 0, M+N, 0; 0, M+N, H; 0, M, H], L, 'Quads');
% Combine the cuboid and cross member geometries
gd = [g; g2];
% Create the mesh
hmax = 0.05; % maximum element size
[p, t] = generateMesh(gd, 'Hmax', hmax);
% Get the connectivity matrix
C = connectivityMatrix(t);
You can refer to the generateMesh documentation from the below link
