Changes

Impenetrable, penetrable and terrain surfaces and penetrable volumes represent buildings, blocks or objects that obstruct the propagation of electromagnetic waves (rays) in the free space. What differentiates them is the types of physical phenomena that are used to model their interaction with the impinging rays.  In a SBR simulation, the propagating rays hit the surface of building structures, walls, terrain (or global ground) and bounce back into the scene (reflection). Some rays penetrate thin walls or other penetrable surfaces and continue their path on the other side of the surface (transmission). The field intensity, phase and power of the reflected and transmitted rays depend on the material properties of the obstructing surface. The specular surface can be modeled as a simple homogeneous dielectric half-space or as a multilayer structure. In that respect, the buildings, walls, terrain or even the global ground all behave in a similar way:

[[EM.CubeTerrano]] has generalized the concept of '''Block''' as any object that obstructs and affects radio wave propagation. Rays hit the facets of a block and bounce off the surface of those facets or penetrate them and continue their propagation. Rays also get diffracted off the edges of these blocks.   In [[EM.Cube]]'s [[Propagation Module]], blocks are grouped together by the type of their interaction with rays. [[EM.Cube]] currently offers three types of blocks for use in a propagation scene: