MATLAB: How to model multiple regions in extruded 2.5D geometries using the PDE Toolbox

Question

How to model multiple regions in extruded 2.5D geometries using the PDE Toolbox?

Answer 1

Refer to the attached example script, which illustrates one approach to do this. The script is very similar to creating geometry using 'geometryFromMesh' in conjunction with 'alphaShape' as demonstrated in the following documentation link:

https://www.mathworks.com/help/releases/R2018b/pde/ug/pde.pdemodel.geometryfrommesh.html#buvmj0q-1

The major differences are:

1. We need to define the entire geometry and its regions separately using 'alphaShape'.

2. We need to use 'inShape' to get the mapping 'ElementIDToRegionID' and pass it as a fourth parameter to 'geometryFromMesh'.

3. We need to use 'alphaTriangulation' command instead of 'boundaryFacets'. 'boundaryFacets' will simply give one contiguous region.