If input data consists of polygons specified as arrays of corner points coordinates, you can use the following approach to create geometry for pde model:
- Build a geometry description matrix using the polygon data
- Use decsg function to construct decomposed geometry matrix
- Use geometryFromEdges function to add geometry to PDE model container
Here is a code example that constructs geometry from 4 simple polygons:
% polygon 1
x1 = [0 1 1 0];
y1 = [0 0 1 1];
% polygon 2
x2 = [1 2 2 1];
y2 = [0 0 1 1];
% polygon 3
x3 = [0.5 1.5 1.5 0.5];
y3 = [0.5 0.5 1.5 1.5];
% polygon 4
x4 = [0.2 0.4 0.3];
y4 = [0.2 0.2 0.4];
% build geometry description matrix (each column describes a shape)
p1 = [2 4 x1 y1];
p2 = [2 4 x2 y2];
p3 = [2 4 x3 y3];
p4 = [2 3 x4 y4 0 0];
gd = [p1' p2' p3' p4'];
figure
hold on
plot(polyshape(x1,y1));
plot(polyshape(x2,y2));
plot(polyshape(x3,y3));
plot(polyshape(x4,y4));
% example 1: combine P1, P2, P3, P4
d = decsg(gd);
pdem = createpde;
geometryFromEdges(pdem,d);
figure
pdegplot(pdem,'EdgeLabels','on','FaceLabels','on');
% example 2: combine P1, P2, P3 and leave void P4
d = decsg(gd,'P1-P4+P2+P3',char('P1','P2','P3','P4')');
pdem = createpde;
geometryFromEdges(pdem,d);
figure
pdegplot(pdem,'EdgeLabels','on','FaceLabels','on');
