adaptive mesh refinement for 3d shapes

Hello,

I imported a 3d stl shape in matlab and i would like to refine a mesh of a part of my domain with a defined x ,y , z.....as i know it isn't possible for 3d shapes but If anyone has an opinion, I would appreciate it.

this is my code i like to have a Hmax=1um for my region and Hmax=8um for other parts...but up to now i can just plot my region and can't define adaptive mesh for it.

"clc;

clear;

model = createpde;

gmbearing = importGeometry(model, "s2my_alpha_shape1000.stl");

mesh=generateMesh(model,"Hmax",8e-6,"GeometricOrder","quadratic");

% Obtain node coordinates and tetrahedral connectivity

nodes = mesh.Nodes;

tets = mesh.Elements;

fig1=figure(1);

pdegplot(gmbearing,"CellLabels","on","FaceAlpha",0.2,"FaceLabels","on")

title('Geometry');

xlabel('x-coordinate')

ylabel('y-coordinate')

zlabel('z-coordinate')

figure(2);

pdeplot3D(model);

title('Mesh Visualization');

%%

elemIDs=findElements(mesh,"box",[-0.12e-3 0.12e-3],[-0.45e-3 0.45e-3],[0 1e-5]);

figure(3)

pdemesh(model)

hold on

pdemesh(mesh.Nodes,mesh.Elements(:,elemIDs),"EdgeColor","red")"

Answer 1

[Yatharth]

Hi Saeed,

I understand that you are facing an issue with creating an adaptive mesh for a 3D STL geometry in MATLAB, specifically refining a mesh in a localized region to a smaller element size.

Looking at your code I can see you are using “Hmax” in “generateMesh” function to have a target maximum element size. Looking at your workflow you can use “refinemesh” function to refine the mesh in a specific region after generating an initial coarse mesh. Here is the link to the documentation of the function. https://www.mathworks.com/help/pde/ug/refinemesh.html

You can also look into the following function “geometryFromMesh” to create geometry within the model. Here is the documentation for the same. https://www.mathworks.com/help/pde/ug/pde.pdemodel.geometryfrommesh.html

I hope this helps.