how do divide like this picture by code matlab?

[Walter Roberson]

See https://www.mathworks.com/matlabcentral/answers/132526-structured-quadrilateral-mesh-in-pde-toolbox

[Vuong]

thanks. But i don't have the license PDE toolbox

[Walter Roberson]

Note the reference in the comments there to third party FEA Toolbox (which appears to be a license product)

Answer 1

[Sam Chak]

Hi @Vuong

If this is a topic of Finite Element Analysis, then look up generateMesh() and pdemesh().

gm = fegeometry(@lshapeg);
gm = generateMesh(gm);
pdemesh(gm)

[Vuong]

Thanks. But this is tri element not quad element

[Vuong]

unstructured quadrilateral grid generation

[Sam Chak]

Hi @Vuong

Another option is to use the FEATool Multiphysics toolbox. A license is required for purchase, but discounted academic pricing is available for accredited degree-granting institutions.

Alternatively, you may consider creating your own quadrilateral meshes using various techniques at your disposal. One approach is to utilize Delaunay triangulation; as you may know, if two triangles share a common side and their other vertices are not collinear, the combined figure forms a quadrilateral.

The rest is to find a MATLAB clever way to "remove" the display of the shared common sides.

P   = rand([5 2]);
DT  = delaunayTriangulation(P)

DT = 
  delaunayTriangulation with properties:

              Points: [5x2 double]
    ConnectivityList: [4x3 double]
         Constraints: []

IC  = incenter(DT);
triplot(DT)
hold on
plot(IC(:,1), IC(:,2), '*r'), grid on

●

[Sam Chak]

Hi @Vuong

You can possibly get some inspirations and ideas from this working example:

https://www.mathworks.com/help/matlab/math/delaunay-triangulation.html

[Vuong]

I want to divide area base unstructured quadrilateral mesh by codes matlab not addins or app. Quadrilateral not triangles. Like this figure toppic