Building units are spatial objects aimed at subdividing buildings and/or building parts into smaller parts that are treated as seperate entities in daily life. A building unit is homogeneous, regarding management aspects. EXAMPLES: It may be e.g. an apartment in a condominium, a terraced house, or a shop inside a shopping arcade. NOTE 1: According to national regulations, a building unit may be a flat, a cellar, a garage or set of a flat, a cellar and a garage. NOTE 2: According to national regulation, a building that is one entity for daily life (typically, a single family house) may be considered as a Building composed of one BuildingUnit or as a Building composed of zero BuildingUnit.