Create/Export .stl file from a mesh

Hello,

I have created a model and used generateMesh function that created a mesh and stored it to a model object.

smodel = createpde('structural', 'static-solid');
importGeometry(smodel, 'SquareBeam.STL');
msh = generateMesh(smodel, 'GeometricOrder','linear','Hmin',50);
pdemesh(msh);

Now, I'd like to write this structure to a stl file. I have found stlWrite function in the File Exchange but this function takes faces and vertices as input parameters.

https://www.mathworks.com/matlabcentral/fileexchange/20922-stlwrite-write-ascii-or-binary-stl-files

Is there any way I can extract this data from msh object created in the code above?

Thank you.

Answer 1

[Cris LaPierre]

You can use the stlwrite function that ships with MATLAB. However, you do need to turn your mesh into a triangulation opject first. I'm not sure I found the best way to do this, but my solution is based on this answer:

https://www.mathworks.com/matlabcentral/answers/473495-stlwrite-error-tetrahedron-triangulation-is-not-supported

smodel = createpde('structural', 'static-solid');
importGeometry(smodel, 'SquareBeam.stl');
pdegplot(smodel)

msh = generateMesh(smodel, 'GeometricOrder','linear','Hmin',50);
pdemesh(msh)

% Extract the edge nodes
N = findNodes(msh,"region","Edge",1:smodel.Geometry.NumEdges);
% Convert to alphashape
shp = alphaShape(msh.Nodes(:,N)');
figure
plot(shp)

% Create triangulation
[T, P] = boundaryFacets(shp);
TR = triangulation(T, P);
stlwrite(TR, 'myMesh.stl');

% check result
bmodel = createpde('structural', 'static-solid');
importGeometry(bmodel, 'myMesh.stl');
pdegplot(bmodel)