5.4.3.41 IfcRelSpaceBoundary1stLevel

Limites d'espace de premier niveau
Raumgrenzen 1. Ebene - Relation

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 139, 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

Figure 139 — 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.


XSD Specification:

 <xs:element name="IfcRelSpaceBoundary1stLevel" type="ifc:IfcRelSpaceBoundary1stLevel" substitutionGroup="ifc:IfcRelSpaceBoundary" nillable="true"/>
 <xs:complexType name="IfcRelSpaceBoundary1stLevel">
  <xs:complexContent>
   <xs:extension base="ifc:IfcRelSpaceBoundary">
    <xs:sequence>
     <xs:element name="ParentBoundary" type="ifc:IfcRelSpaceBoundary1stLevel" nillable="true" minOccurs="0"/>
    </xs:sequence>
   </xs:extension>
  </xs:complexContent>
 </xs:complexType>

EXPRESS Specification:

ENTITY IfcRelSpaceBoundary1stLevel
SUPERTYPE OF(IfcRelSpaceBoundary2ndLevel)
SUBTYPE OF IfcRelSpaceBoundary;
ParentBoundary : OPTIONAL IfcRelSpaceBoundary1stLevel;
INVERSE
InnerBoundaries : SET OF IfcRelSpaceBoundary1stLevel FOR ParentBoundary;
END_ENTITY;

Link to EXPRESS-G diagram EXPRESS-G diagram

Attribute Definitions:

ParentBoundary : Reference to the host, or parent, space boundary within which this inner boundary is defined.
InnerBoundaries : Reference to the inner boundaries of the space boundary. Inner boundaries are defined by the space boundaries of openings, doors and windows.

Inheritance Graph:

ENTITY IfcRelSpaceBoundary1stLevel
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;
END_ENTITY;

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