The 1st level space boundary defines the physical or virtual delimiter of a space by the relationship IfcRelSpaceBoundary1stLevel to the surrounding elements. 1st level space boundaries are characterizeda by:
1st level space boundaries define a space by its boundary surfaces without taking anything on the other side of the bounding elements into account.
NOTE 1st level space boundaries are used e.g. in quantity take-off and facility management as they describe the surfaces for finishes. They cannot be directly used for thermal analysis. However 1st level space boundaries can provide the input to preprocessors to thermal analysis software that take 1st level space boundaries and perform the necessary transformation into 2nd level space boundaries that are required for energy analysis.
HISTORY New entity in IFC4.
Relationship Use Definitions
As shown in Figure 1, the attribute ParentBoundary with inverse InnerBoundaries is provided to link the space boundaries of doors, windows, and openings to the parent boundary, such as of a wall or slab.
NOTE The space boundary of the parent is not cut by the inner boundary - both overlap.
IfcRelSpaceBoundary1stLevel"' src="../figures/ifcrelspaceboundary1stlevel-fig1.png" title="Figure 1 — Space boundary first level relationships"/>
Geometry Use Definitions
See the definition at the supertype IfcRelSpaceBoundary for guidance on using the connection geometry for first level space boundaries.
|1||GlobalId||IfcGloballyUniqueId||Assignment of a globally unique identifier within the entire software world.|
|2||OwnerHistory||OPTIONAL IfcOwnerHistory||Assignment of the information about the current ownership of that object, including owning actor, application, local identification and information captured about the recent changes of the object, |
> NOTE only the last modification in stored - either as addition, deletion or modification.
> IFC4 CHANGE The attribute has been changed to be OPTIONAL.
|3||Name||OPTIONAL IfcLabel||Optional name for use by the participating software systems or users. For some subtypes of IfcRoot the insertion of the Name attribute may be required. This would be enforced by a where rule.|
|4||Description||OPTIONAL IfcText||Optional description, provided for exchanging informative comments.|
|5||RelatingSpace||IfcSpaceBoundarySelect||Reference to one spaces that is delimited by this boundary.|
|6||RelatedBuildingElement||IfcElement||Reference to ~~Building~~ Element, that defines the Space Boundaries.|
> IFC2x CHANGE The data type has been changed from IfcBuildingElement to IfcElement with upward compatibility for file based exchange.
> IFC4 CHANGE The attribute has been changed to be mandatory.
|7||ConnectionGeometry||OPTIONAL IfcConnectionGeometry||Physical representation of the space boundary. Provided as a **curve or** surface given within the LCS of the space.|
> IFC2x CHANGE The data type has been changed from IfcConnectionSurfaceGeometry to IfcConnectionGeometry with upward compatibility for file based exchange.
|8||PhysicalOrVirtualBoundary||IfcPhysicalOrVirtualEnum||Defines, whether the Space Boundary is physical (Physical) or virtual (Virtual).|
|9||InternalOrExternalBoundary||IfcInternalOrExternalEnum||Defines, whether the Space Boundary is internal (Internal), or external, i.e. adjacent to open space (that can be an partially enclosed space, such as terrace (External).|
|10||ParentBoundary||OPTIONAL IfcRelSpaceBoundary1stLevel||Reference to the host, or parent, space boundary within which this inner boundary is defined.|
|InnerBoundaries||SET [0:?] OF IfcRelSpaceBoundary1stLevel FOR ParentBoundary||Reference to the inner boundaries of the space boundary. Inner boundaries are defined by the space boundaries of openings, doors and windows.|
IfcRoot assigns the globally unique ID. In addition it may provide for a name and a description about the concept.
Ownership, history, and merge state is captured using IfcOwnerHistory.
ENTITY IfcRelSpaceBoundary1stLevel SUPERTYPE OF (ONEOF (IfcRelSpaceBoundary2ndLevel)) SUBTYPE OF (IfcRelSpaceBoundary); ParentBoundary : OPTIONAL IfcRelSpaceBoundary1stLevel; INVERSE InnerBoundaries : SET [0:?] OF IfcRelSpaceBoundary1stLevel FOR ParentBoundary; END_ENTITY;