Geometry from polyshape

This example shows how to create a polygonal geometry using the MATLAB® polyshape function. Then use the triangulated representation of the geometry to create an fegeometry object.

Create and plot a polyshape object of a square with a hole.

t = pi/12:pi/12:2*pi;
pgon = polyshape({[-0.5 -0.5 0.5 0.5], 0.25*cos(t)}, ...
                 {[0.5 -0.5 -0.5 0.5], 0.25*sin(t)})

pgon = 
  polyshape with properties:

      Vertices: [29×2 double]
    NumRegions: 1
      NumHoles: 1

plot(pgon)
axis equal

Create a triangulation representation of this object.

tr = triangulation(pgon);

Create a geometry by using the triangulation data.

gm = fegeometry(tr)

gm = 
  fegeometry with properties:

       NumCells: 0
       NumFaces: 1
       NumEdges: 5
    NumVertices: 5
       Vertices: [5×3 double]
           Mesh: [1×1 FEMesh]

Plot the geometry.

pdegplot(gm);

Because the triangulation data results in a low-quality linear mesh, generate a new finer mesh for further analysis.

gm = generateMesh(gm);
gm.Mesh

ans = 
  FEMesh with properties:

             Nodes: [2×1244 double]
          Elements: [6×572 double]
    MaxElementSize: 0.0566
    MinElementSize: 0.0283
     MeshGradation: 1.5000
    GeometricOrder: 'quadratic'

Plot the mesh.

pdemesh(gm);