PDE Toolbox STL Import with Incorrect Faces

I am attempting to import 3D geometry into the PDE Toolbox via the importGeometry function. The import works correctly, however, the faces are not properly labeled. In short, the toolbox is claiming there are only 6 faces for the following geometry when there are clearly many more. Has anyone had any similar experiences? Is there a fix?

Answer 1

[M S]

Hello,

We are having the same problems regarding an imported STL file. It does not recognize all faces. I hope we will get some answer from mathworks.

Best

[Sleh Eddine Brika]

No it's not a problem with the STL file when using this command hc=pdegplot(model,'FaceLabels','on'); and extract the faces, vertices and Edges like this E= [(hc(2).XData)' (hc(2).YData)' (hc(2).ZData)']%Edges V=hc(1).Vertices;%Vertices F=hc(1).Faces;%Faces but the faces that I extracted my self are not the same as the ones ploted. For exemple if I have a square, the command pdegplot(model,'FaceLabels','on') will label one face, but the matrix F will have 2. I don't know how it's work ! I think that the fonction find a relation between faces/edges/vertices to detect the labeled faces but I didn't figure out how it's work.

Answer 2

[Michael Carkin]

This is what technical support had to offer:

"After consulting with my colleagues in development, the behavior you are experiencing is the expected behavior. The STL format comprises a collection of triangles that make up the boundary of the CAD model and the PDE Toolbox reconstructs the Face/Edge/Vertex topology from that data. Unlike an IGES or STEP import where the topology is fully preserved, the reconstruction from STL is imprecise resulting in the loss of edges and merging of adjacent faces."

Two Points:

1: The PDE Toolbox does not allow IGES or STEP file imports.

2: I have never run into a similar issue with another program (ANSYS, COMSOL, Meshing software, etc).

From the sounds of it they do not plan to fix the issue as it is working just fine in their opinion. Best of luck with a real solution.