4.1.5.13.2 Spatial Containment

The Spatial Containment concept defines the relationship of physical elements, such as building elements, distribution elements, or furnishing elements as being contained within a spatial structure element.

Any subtype of IfcElement may participate in two different containment relationships. The first (and in most implementation scenarios mandatory) relationship is the hierarchical spatial containment, the second (optional) relationship is the aggregation within an element assembly.

• The subtypes of IfcElement are placed within the project spatial hierarchy using the objectified relationship IfcRelContainedInSpatialStructure, referring to it by its inverse attribute SELF\IfcElement.ContainedInStructure. Subtypes of IfcSpatialElement are valid spatial containers.
• The subtypes of IfcElement may be aggregated into an element assembly using the objectified relationship IfcRelAggregates, referring to it by its inverse attribute SELF\IfcObjectDefinition.Decomposes. Any subtype of IfcElement can be an element assembly, with IfcElementAssembly as a special focus subtype. In this case it should not be additionally contained in the project spatial hierarchy, i.e. SELF\IfcElement.ContainedInStructure should be NIL.

The following diagram shows the generic classes and relationships used when applying this concept. In addition, concepts may have particular importance to common or standardised industry practices and scenarios. For these specific usage scenarios, the table below shows a recommended list of general usage patterns that users may adopt.

General Usage

ApplicableEntity	RelatingStructure IfcRelContainedInSpatialStructure.RelatingStructure
IfcAnnotation	IfcSpatialElement
IfcElement	IfcSpatialElement
IfcGrid	IfcSpatialElement