5.4.3.42 IfcRelSpaceBoundary2ndLevel

Limites d'espace de deuxième niveau
Raumgrenzen 2. Ebene - Relation

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 140, 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 140 — 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.


XSD 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

Attribute Definitions:

CorrespondingBoundary : Reference to the other space boundary of the pair of two space boundaries on either side of a space separating thermal boundary element.
Corresponds : Reference to the other space boundary of the pair of two space boundaries on either side of a space separating thermal boundary element.

Inheritance Graph:

ENTITY IfcRelSpaceBoundary2ndLevel
ENTITY IfcRoot
GlobalId : IfcGloballyUniqueId;
OwnerHistory : OPTIONAL IfcOwnerHistory;
Name : OPTIONAL IfcLabel;
Description : OPTIONAL IfcText;
ENTITY IfcRelationship
ENTITY IfcRelConnects
ENTITY IfcRelSpaceBoundary
RelatingSpace : IfcSpaceBoundarySelect;
RelatedBuildingElement : IfcElement;
ConnectionGeometry : OPTIONAL IfcConnectionGeometry;
PhysicalOrVirtualBoundary : IfcPhysicalOrVirtualEnum;
InternalOrExternalBoundary : IfcInternalOrExternalEnum;
ENTITY IfcRelSpaceBoundary1stLevel
ParentBoundary : OPTIONAL IfcRelSpaceBoundary1stLevel;
INVERSE
InnerBoundaries : SET OF IfcRelSpaceBoundary1stLevel FOR ParentBoundary;
ENTITY IfcRelSpaceBoundary2ndLevel
CorrespondingBoundary : OPTIONAL IfcRelSpaceBoundary2ndLevel;
INVERSE
Corresponds : SET [0:1] OF IfcRelSpaceBoundary2ndLevel FOR CorrespondingBoundary;
END_ENTITY;

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