IfcRelSpaceBoundary2ndLevel

Natural language names
Raumgrenzen 2. Ebene - Relation
Rel Space Boundary2nd Level
Limites d'espace de deuxième niveau
Change log
ItemSPFXMLChangeDescription
IFC2x3 to IFC4 4.0.0.0
    IfcRelSpaceBoundary2ndLevelADDED
Semantic definitions at the entity
Entity definition

The 2nd level space boundary defines the physical or virtual delimiter of a space by the relationship IfcRelSpaceBoundary2ndLevel to the surrounding elements. 2nd level space boundaries are characterized by:

2nd level space boundaries define the heat transfer surfaces on both sides of building elements that separate spaces. The generation of 2nd level space boundaries has to take building elements and spaces on the other side into account.

NOTE  2nd level space boundaries are used by many analysis packages that require a surface view of the building that can be transformed into the various simple topological models. Examples of such analysis packages include: (1) energy analysis, (2) lighting analysis, (3) fluid dynamics

HISTORY  New entity in IFC4.

Relationship Use Definitions

As shown in Figure 175, 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.

The attribute CorrespondingBoundary with inverse Corresponds is provided to link the pair of space boundaries on the opposite sides of the building element.

NOTE  Only 2nd level space boundaries of type A have corresponding boundaries.

"IfcRelSpaceBoundary2ndLevel"

Figure 175 — Space boundary second level relationships

Geometry Use Definitions

See the definition at the supertype IfcRelSpaceBoundary for guidance on using the connection geometry for second level space boundaries.

Attribute definitions
#AttributeTypeCardinalityDescription G
11CorrespondingBoundaryIfcRelSpaceBoundary2ndLevel? Reference to the other space boundary of the pair of two space boundaries on either side of a space separating thermal boundary element. X
CorrespondsIfcRelSpaceBoundary2ndLevel
@CorrespondingBoundary
S[0:1]Reference to the other space boundary of the pair of two space boundaries on either side of a space separating thermal boundary element. X
Inherited definitions from supertypes
Entity inheritance IfcRelSpaceBoundary1stLevel IfcRelSpaceBoundary IfcRelConnects IfcRelationship IfcRoot
Attribute inheritance
#AttributeTypeCardinalityDescriptionG
IfcRoot
1GlobalIdIfcGloballyUniqueId Assignment of a globally unique identifier within the entire software world. X
2OwnerHistoryIfcOwnerHistory? 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.
X
3NameIfcLabel? 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. X
4DescriptionIfcText? Optional description, provided for exchanging informative comments. X
IfcRelationship
IfcRelConnects
IfcRelSpaceBoundary
5RelatingSpaceIfcSpaceBoundarySelect Reference to one spaces that is delimited by this boundary. X
6RelatedBuildingElementIfcElement 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.
X
7ConnectionGeometryIfcConnectionGeometry? 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.
X
8PhysicalOrVirtualBoundaryIfcPhysicalOrVirtualEnum Defines, whether the Space Boundary is physical (Physical) or virtual (Virtual). X
9InternalOrExternalBoundaryIfcInternalOrExternalEnum 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). X
IfcRelSpaceBoundary1stLevel
10ParentBoundaryIfcRelSpaceBoundary1stLevel? Reference to the host, or parent, space boundary within which this inner boundary is defined. X
InnerBoundariesIfcRelSpaceBoundary1stLevel
@ParentBoundary
S[0:?]Reference to the inner boundaries of the space boundary. Inner boundaries are defined by the space boundaries of openings, doors and windows. X
IfcRelSpaceBoundary2ndLevel
11CorrespondingBoundaryIfcRelSpaceBoundary2ndLevel? Reference to the other space boundary of the pair of two space boundaries on either side of a space separating thermal boundary element. X
CorrespondsIfcRelSpaceBoundary2ndLevel
@CorrespondingBoundary
S[0:1]Reference to the other space boundary of the pair of two space boundaries on either side of a space separating thermal boundary element. X
Definitions applying to General Usage

Concept inheritance

#ConceptTemplateModel View
IfcRoot
IdentitySoftware IdentityGeneral Usage
Revision ControlRevision ControlGeneral Usage
Formal representations
XML Specification
 <xs:element name="IfcRelSpaceBoundary2ndLevel" type="ifc:IfcRelSpaceBoundary2ndLevel" substitutionGroup="ifc:IfcRelSpaceBoundary1stLevel" nillable="true"/>
 <xs:complexType name="IfcRelSpaceBoundary2ndLevel">
  <xs:complexContent>
   <xs:extension base="ifc:IfcRelSpaceBoundary1stLevel">
    <xs:sequence>
     <xs:element name="CorrespondingBoundary" type="ifc:IfcRelSpaceBoundary2ndLevel" nillable="true" minOccurs="0"/>
    </xs:sequence>
   </xs:extension>
  </xs:complexContent>
 </xs:complexType>
EXPRESS Specification
ENTITY IfcRelSpaceBoundary2ndLevel
 SUBTYPE OF (IfcRelSpaceBoundary1stLevel);
  CorrespondingBoundary : OPTIONAL IfcRelSpaceBoundary2ndLevel;
 INVERSE
  Corresponds : SET [0:1] OF IfcRelSpaceBoundary2ndLevel FOR CorrespondingBoundary;
END_ENTITY;

Link to EXPRESS-G diagram EXPRESS-G diagram

References  References: IfcRelSpaceBoundary2ndLevel

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