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 as an input mesh for the geometryFromMesh function.

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: [29x2 double]
    NumRegions: 1
      NumHoles: 1

plot(pgon)
axis equal

Create a triangulation representation of this object.

tr = triangulation(pgon);

Create a PDE model.

model = createpde;

With the triangulation data as a mesh, use the geometryFromMesh function to create a geometry. Plot the geometry.

tnodes = tr.Points';
telements = tr.ConnectivityList';

geometryFromMesh(model,tnodes,telements);
pdegplot(model)

Plot the mesh.

figure
pdemesh(model)

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

generateMesh(model)
ans = 
  FEMesh with properties:

             Nodes: [2x1259 double]
          Elements: [6x579 double]
    MaxElementSize: 0.0566
    MinElementSize: 0.0283
     MeshGradation: 1.5000
    GeometricOrder: 'quadratic'

Plot the mesh.

figure
pdemesh(model)