A curtain wall is an exterior wall of a building which is
an assembly of components, hung from the edge of the floor/roof
structure rather than bearing on a floor. Curtain wall is
represented as a building element assembly and implemented as a
subtype of IfcBuildingElement that uses an
NOTE Definition according to ISO 6707-1:
non load bearing wall positioned on the outside of a building and enclosing it.
HISTORY New entity in IFC2.0
The geometric representation of IfcCurtainWall is given by the IfcProductDefinitionShape, allowing multiple
geometric representations. Independent 'Body' geometric representation, as described below, should only be used when the
IfcCurtainWall is not defined as an aggregate. If defined as an aggregate, the geometric representation is the sum of the
representations of the components within the aggregate.
The geometric representation of IfcCurtainWall is defined using the following multiple shape representations for
- Axis: A two-dimensional open curve (for restrictions see below) defining the axis for the curtain wall.
- This is an optional representation for curtain walls.
- Body: A surface model or boundary representation model representation defining the 3D shape of the curtain wall.
- If the IfcCurtainWall has components (referenced by SELF\IfcObject.IsDecomposedBy) then no independent shape
representation with RepresentationType = 'Body' shall be defined. The body of IfcCurtainWall is then geometrically
represented by the shape representation of its components. The components are accessed via
- If the IfcCurtainWall has no components defined (empty set of SELF\IfcObject.IsDecomposedBy) then the
IfcCurtainWall may be represented by an shape representation with the RepresentationIdentifier ='Body'.
Common Use Definitions
The following concepts are inherited at supertypes:
- IfcRoot: Identity, Revision Control
- IfcElement: Box Geometry, FootPrint Geometry, Body SurfaceOrSolidModel Geometry, Body SurfaceModel Geometry, Body Tessellation Geometry, Body Brep Geometry, Body AdvancedBrep Geometry, Body CSG Geometry, Mapped Geometry
- IfcBuildingElement: Product Assignment, Surface 3D Geometry
The Object Typing concept applies to this entity as shown in Table 114.
Table 114 — IfcCurtainWall Object Typing
Property Sets for Objects
The Property Sets for Objects concept applies to this entity as shown in Table 115.
Table 115 — IfcCurtainWall Property Sets for Objects
The Quantity Sets concept applies to this entity as shown in Table 116.
Table 116 — IfcCurtainWall Quantity Sets
The Spatial Containment concept applies to this entity as shown in Table 117.
|IfcBuildingStorey||Default spatial container |
|IfcBuilding||Spatial container for the element if it cannot be assigned to a building storey - curtain wall facades may be assigned directly to the building|
|IfcSite||Spatial container for the element in case that it is placed on site (outside of building)|
Table 117 — IfcCurtainWall Spatial Containment
The Product Placement concept applies to this entity as shown in Table 118.
Table 118 — IfcCurtainWall Product Placement
The following restriction may be imposed by view definitions or implementer agreements:
- If the IfcCurtainWall establishes an aggregate, then
all contained elements shall be placed relative to the
Axis 2D Geometry
The Axis 2D Geometry concept applies to this entity.
The following additional constraints apply to the 'Axis'
XSD Specification: <xs:element name="IfcCurtainWall" type="ifc:IfcCurtainWall" substitutionGroup="ifc:IfcBuildingElement" nillable="true"/>
<xs:attribute name="PredefinedType" type="ifc:IfcCurtainWallTypeEnum" use="optional"/>
|CorrectPredefinedType|| : ||NOT(EXISTS(PredefinedType)) OR
(PredefinedType <> IfcCurtainWallTypeEnum.USERDEFINED) OR
((PredefinedType = IfcCurtainWallTypeEnum.USERDEFINED) AND EXISTS (SELF\IfcObject.ObjectType));|
|CorrectTypeAssigned|| : ||(SIZEOF(IsTypedBy) = 0) OR
('IFCSHAREDBLDGELEMENTS.IFCCURTAINWALLTYPE' IN TYPEOF(SELF\IfcObject.IsTypedBy.RelatingType));|
|PredefinedType|| : ||
Predefined generic type for a curtain wall that is specified in an enumeration. There may be a property set given specificly for the predefined types.
NOTE The PredefinedType shall only be used, if no IfcCurtainWallType is assigned, providing its own IfcCurtainWallType.PredefinedType.
IFC4 CHANGE The attribute has been added at the end of the entity definition.
|CorrectPredefinedType|| : ||
Either the PredefinedType attribute is unset (e.g. because an IfcCurtainWallType is associated), or the inherited attribute ObjectType shall be provided, if the PredefinedType is set to USERDEFINED.
|CorrectTypeAssigned|| : ||
Either there is no curtain wall type object associated, i.e. the IsTypedBy inverse relationship is not provided, or the associated type object has to be of type IfcCurtainWallType.
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