* '''[[Block_Types#Impenetrable_Surfaces_for_Outdoor_Scenes|Impenetrable Surfaces]]''': feature reflection and diffraction of impinging rays. Rays hit the facets of this type of blocks and bounce back, but they do not penetrate the object. It is assumed that the interior of such blocks or buildings are highly absorptive.
* '''[[Block_Types#Penetrable_Volumes|Penetrable Volumes]]''': feature reflection, transmission and diffraction of impinging rays. These blocks are used to model propagation inside general material media or fog, rain and vegetation.
* '''[[Block_Types#Penetrable_Surfaces_for_Indoor_Scenes|Penetrable Surfaces]]''': feature reflection, transmission and diffraction of impinging rays. These blocks represent thin surfaces that are used to model the exterior and interior walls of buildings. Rays reflect off the surface of penetrable surfaces and diffract off their edges. They also penetrate the thin surface and continue their path in the free space on the other side of the wall.
* '''[[Block_Types#Terrain_Surfaces_vs._Global_Ground|Terrain Surfaces]]''': feature reflection and optional diffraction of impinging rays. These blocks are used to provide one or more impenetrable, ground surfaces for the propagation scene. Rays simply bounce off terrain objects.
* '''[[#Defining_Base_Point_Sets|Base Points]]''': are used to define transmitter and receiver locations in the scene.
=== Adding a New Scene Element ===