IfcRelSpaceBoundary1stLevel

Natural language names
Raumgrenzen 1. Ebene - Relation
Rel Space Boundary1st Level
Limites d'espace de premier niveau
Change log
ItemSPFXMLChangeDescription
IFC2x3 to IFC4 4.0.0.0
    IfcRelSpaceBoundary1stLevelADDED
Semantic definitions at the entity
Entity definition

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 336, 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 336 — 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.

Attribute definitions
#AttributeTypeCardinalityDescription G
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
Inherited definitions from supertypes
Entity inheritance IfcRelSpaceBoundary2ndLevel 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
Definitions applying to General Usage

Concept inheritance

#ConceptTemplateModel View
IfcRoot
IdentitySoftware IdentityGeneral Usage
Revision ControlRevision ControlGeneral Usage
Formal representations
XML 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 [0:?] OF IfcRelSpaceBoundary1stLevel FOR ParentBoundary;
END_ENTITY;

Link to EXPRESS-G diagram EXPRESS-G diagram

References  References: IfcRelSpaceBoundary1stLevel

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