[[Image:MAT1.png|thumb|400px|A structure made up of a PEC plate and different dielectric materials.]]
Your '''Physical Structure''' A physical structure in [[EM.Cube]] consists in made up of a number of CAD geometric objects you either draw in the project workspaceor import from an external CAD model file. In all [[EM.Cube]] modules, you use [[CubeCAD]]'s common drawing tools and/or its import capability to construct your geometrical structure. In order to perform an electromagnetic simulation, you need to assign material properties to all of your CAD objects in the project workspace. The drawn CAD objects are organized together based on their common properties under one or more object groups or nodes in the '''Navigation Tree'''. The grouping of CAD objects is essentially based on their material composition and their associated boundary conditions.
Among [[EM.Cube]]'s computational modules, [[EM.Tempo]] is the most comprehensive in view of material variety offering. [[EM.Ferma]] and [[EM.Libera]] offer PEC and dielectric material groups similar to [[EM.Tempo]]. [[EM.Illumina]] offers PEC, PMC and impedance surfaces. [[EM.Terrano]] groups objects into material [[Block Types|block types]] that are characterized by their ray interaction properties. [[EM.Picasso]] groups objects based on their trace location (i.e. Z-coordinate) in the substrate layer hierarchy.