Realistic 3D models

Medusa is not meant to deal with complex 3D geometry - we support balls, cuboids, and their differences, unions, translations and rotations. More general 2D shapes can be described by polygons, which are also included in Medusa. For more general 3D objects, the geometric algorithms become more complex and it makes sense to leverage third-party libraries. A good library in c++ is CGAL ([1]), that we can use to work with polyhedrons: [2]

Polyhedrons are solid bodies with polygonal faces, and their surface forms a closed mesh. CGAL can work also with surfaces meshes that are not closed, but for PDE solving in 3D bodies, we assume them to be closed (or watertight). Polyhedron data is usually stored in a separate file with many different formats available. Some of the formats actually store the polyhedron data (including how faces are connected) and some only store the faces.