IfcCurtainWall

Semantic definitions at the entity

Entity definition

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 IfcRelAggregates relationship.

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 its definition:

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 SELF\IfcObject.IsDecomposedBy[1].RelatedObjects.
- 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'.

Attribute definitions

#	Attribute	Type	Cardinality	Description	G
9	PredefinedType	IfcCurtainWallTypeEnum	?	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.	X

Attribute

Type

Cardinality

Description

PredefinedType

IfcCurtainWallTypeEnum

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.

Formal Propositions

Rule	Description
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.

Inherited definitions from supertypes

Entity inheritance

Attribute inheritance

#	Attribute	Type	Cardinality	Description	G
IfcRoot
1	GlobalId	IfcGloballyUniqueId		Assignment of a globally unique identifier within the entire software world.	X
2	OwnerHistory	IfcOwnerHistory	?	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
3	Name	IfcLabel	?	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
4	Description	IfcText	?	Optional description, provided for exchanging informative comments.	X
IfcObjectDefinition
	HasAssignments	IfcRelAssigns @RelatedObjects	S[0:?]	Reference to the relationship objects, that assign (by an association relationship) other subtypes of IfcObject to this object instance. Examples are the association to products, processes, controls, resources or groups.	X
	Nests	IfcRelNests @RelatedObjects	S[0:1]	References to the decomposition relationship being a nesting. It determines that this object definition is a part within an ordered whole/part decomposition relationship. An object occurrence or type can only be part of a single decomposition (to allow hierarchical strutures only). IFC4 CHANGE The inverse attribute datatype has been added and separated from Decomposes defined at IfcObjectDefinition.	X
	IsNestedBy	IfcRelNests @RelatingObject	S[0:?]	References to the decomposition relationship being a nesting. It determines that this object definition is the whole within an ordered whole/part decomposition relationship. An object or object type can be nested by several other objects (occurrences or types). IFC4 CHANGE The inverse attribute datatype has been added and separated from IsDecomposedBy defined at IfcObjectDefinition.	X
	HasContext	IfcRelDeclares @RelatedDefinitions	S[0:1]	References to the context providing context information such as project unit or representation context. It should only be asserted for the uppermost non-spatial object. IFC4 CHANGE The inverse attribute datatype has been added.	X
	IsDecomposedBy	IfcRelAggregates @RelatingObject	S[0:?]	References to the decomposition relationship being an aggregation. It determines that this object definition is whole within an unordered whole/part decomposition relationship. An object definitions can be aggregated by several other objects (occurrences or parts). IFC4 CHANGE The inverse attribute datatype has been changed from the supertype IfcRelDecomposes to subtype IfcRelAggregates.	X
	Decomposes	IfcRelAggregates @RelatedObjects	S[0:1]	References to the decomposition relationship being an aggregation. It determines that this object definition is a part within an unordered whole/part decomposition relationship. An object definitions can only be part of a single decomposition (to allow hierarchical strutures only). IFC4 CHANGE The inverse attribute datatype has been changed from the supertype IfcRelDecomposes to subtype IfcRelAggregates.	X
	HasAssociations	IfcRelAssociates @RelatedObjects	S[0:?]	Reference to the relationship objects, that associates external references or other resource definitions to the object.. Examples are the association to library, documentation or classification.	X
IfcObject
5	ObjectType	IfcLabel	?	The type denotes a particular type that indicates the object further. The use has to be established at the level of instantiable subtypes. In particular it holds the user defined type, if the enumeration of the attribute PredefinedType is set to USERDEFINED.	X
	IsDeclaredBy	IfcRelDefinesByObject @RelatedObjects	S[0:1]	Link to the relationship object pointing to the declaring object that provides the object definitions for this object occurrence. The declaring object has to be part of an object type decomposition. The associated IfcObject, or its subtypes, contains the specific information (as part of a type, or style, definition), that is common to all reflected instances of the declaring IfcObject, or its subtypes. IFC4 CHANGE New inverse relationship, change made with upward compatibility for file based exchange.	X
	Declares	IfcRelDefinesByObject @RelatingObject	S[0:?]	Link to the relationship object pointing to the reflected object(s) that receives the object definitions. The reflected object has to be part of an object occurrence decomposition. The associated IfcObject, or its subtypes, provides the specific information (as part of a type, or style, definition), that is common to all reflected instances of the declaring IfcObject, or its subtypes. IFC4 CHANGE New inverse relationship, change made with upward compatibility for file based exchange.	X
	IsTypedBy	IfcRelDefinesByType @RelatedObjects	S[0:1]	Set of relationships to the object type that provides the type definitions for this object occurrence. The then associated IfcTypeObject, or its subtypes, contains the specific information (or type, or style), that is common to all instances of IfcObject, or its subtypes, referring to the same type. IFC4 CHANGE New inverse relationship, the link to IfcRelDefinesByType had previously be included in the inverse relationship IfcRelDefines. Change made with upward compatibility for file based exchange.	X
	IsDefinedBy	IfcRelDefinesByProperties @RelatedObjects	S[0:?]	Set of relationships to property set definitions attached to this object. Those statically or dynamically defined properties contain alphanumeric information content that further defines the object. IFC4 CHANGE The data type has been changed from IfcRelDefines to IfcRelDefinesByProperties with upward compatibility for file based exchange.	X
IfcProduct
6	ObjectPlacement	IfcObjectPlacement	?	Placement of the product in space, the placement can either be absolute (relative to the world coordinate system), relative (relative to the object placement of another product), or constraint (e.g. relative to grid axes). It is determined by the various subtypes of IfcObjectPlacement, which includes the axis placement information to determine the transformation for the object coordinate system.	X
7	Representation	IfcProductRepresentation	?	Reference to the representations of the product, being either a representation (IfcProductRepresentation) or as a special case a shape representations (IfcProductDefinitionShape). The product definition shape provides for multiple geometric representations of the shape property of the object within the same object coordinate system, defined by the object placement.	X
	ReferencedBy	IfcRelAssignsToProduct @RelatingProduct	S[0:?]	Reference to the IfcRelAssignsToProduct relationship, by which other products, processes, controls, resources or actors (as subtypes of IfcObjectDefinition) can be related to this product.	X
	PositionedRelativeTo	IfcRelPositions @RelatedProducts	S[0:1]		X
	ReferencedInStructures	IfcRelReferencedInSpatialStructure @RelatedElements	S[0:?]		X
IfcElement
8	Tag	IfcIdentifier	?	The tag (or label) identifier at the particular instance of a product, e.g. the serial number, or the position number. It is the identifier at the occurrence level.	X
	FillsVoids	IfcRelFillsElement @RelatedBuildingElement	S[0:1]	Reference to the IfcRelFillsElement Relationship that puts the element as a filling into the opening created within another element.	X
	ConnectedTo	IfcRelConnectsElements @RelatingElement	S[0:?]	Reference to the element connection relationship. The relationship then refers to the other element to which this element is connected to.	X
	IsInterferedByElements	IfcRelInterferesElements @RelatedElement	S[0:?]	Reference to the interference relationship to indicate the element that is interfered. The relationship, if provided, indicates that this element has an interference with one or many other elements. NOTE There is no indication of precedence between IsInterferedByElements and InterferesElements. IFC4 CHANGE New inverse relationship.	X
	InterferesElements	IfcRelInterferesElements @RelatingElement	S[0:?]	Reference to the interference relationship to indicate the element that interferes. The relationship, if provided, indicates that this element has an interference with one or many other elements. NOTE There is no indication of precedence between IsInterferedByElements and InterferesElements. IFC4 CHANGE New inverse relationship.	X
	HasProjections	IfcRelProjectsElement @RelatingElement	S[0:?]	Projection relationship that adds a feature (using a Boolean union) to the IfcBuildingElement.	X
	HasOpenings	IfcRelVoidsElement @RelatingBuildingElement	S[0:?]	Reference to the IfcRelVoidsElement relationship that creates an opening in an element. An element can incorporate zero-to-many openings. For each opening, that voids the element, a new relationship IfcRelVoidsElement is generated.	X
	IsConnectionRealization	IfcRelConnectsWithRealizingElements @RealizingElements	S[0:?]	Reference to the connection relationship with realizing element. The relationship, if provided, assigns this element as the realizing element to the connection, which provides the physical manifestation of the connection relationship.	X
	ProvidesBoundaries	IfcRelSpaceBoundary @RelatedBuildingElement	S[0:?]	Reference to space boundaries by virtue of the objectified relationship IfcRelSpaceBoundary. It defines the concept of an element bounding spaces.	X
	ConnectedFrom	IfcRelConnectsElements @RelatedElement	S[0:?]	Reference to the element connection relationship. The relationship then refers to the other element that is connected to this element.	X
	ContainedInStructure	IfcRelContainedInSpatialStructure @RelatedElements	S[0:1]	Containment relationship to the spatial structure element, to which the element is primarily associated. This containment relationship has to be hierachical, i.e. an element may only be assigned directly to zero or one spatial structure.	X
	HasCoverings	IfcRelCoversBldgElements @RelatingBuildingElement	S[0:?]	Reference to IfcCovering by virtue of the objectified relationship IfcRelCoversBldgElement. It defines the concept of an element having coverings associated.	X
IfcBuiltElement
IfcCurtainWall
9	PredefinedType	IfcCurtainWallTypeEnum	?	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.	X

Definitions applying to General Usage

Instance diagram

Concept usage

Object Typing

The Object Typing concept template applies to this entity as shown in Table 128.

HasType	RelatingType
	IfcCurtainWallType

Table 128 — IfcCurtainWall Object Typing

Property Sets for Objects

The Property Sets for Objects concept template applies to this entity as shown in Table 129.

PsetName

Properties

Pset_CurtainWallCommon

Template	PropertyName	Value
Single Value	Reference	IfcIdentifier
Single Value	AcousticRating	IfcLabel
Single Value	FireRating	IfcLabel
Single Value	Combustible	IfcBoolean
Single Value	SurfaceSpreadOfFlame	IfcLabel
Single Value	ThermalTransmittance	IfcThermalTransmittanceMeasure
Single Value	IsExternal	IfcBoolean
Enumerated Value	Status	IfcLabel

Table 129 — IfcCurtainWall Property Sets for Objects

Quantity Sets

The Quantity Sets concept template applies to this entity as shown in Table 130.

QsetName	Quantities
Qto_CurtainWallQuantities

Table 130 — IfcCurtainWall Quantity Sets

Spatial Containment

The Spatial Containment concept template applies to this entity as shown in Table 131.

RelatingStructure	Description
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 131 — IfcCurtainWall Spatial Containment

Placement

The Product Local Placement concept template applies to this entity as shown in Table 132.

Table 132 — IfcCurtainWall Product Local 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 IfcCurtainWall.ObjectPlacement.

Axis 2D Geometry

The Axis 2D Geometry concept applies to this entity.

The following additional constraints apply to the 'Axis' representation:

Geometry : IfcPolyline having two Points, or IfcTrimmedCurve with BasisCurve of type IfcLine or IfcCircle.

mvdXML Specification


<?xml version="1.0" encoding="utf-8"?>

<ConceptRoot xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" uuid="a2b0737e-1ff6-4723-b6c3-301cdd2ba38a" name="IfcCurtainWall" applicableRootEntity="IfcCurtainWall">

 <Applicability>

  <Template ref="6eaad21b-bac5-405e-9a2c-bcdc7f76a4f4" />

  <TemplateRules operator="and">

  </TemplateRules>

 </Applicability>

 <Concepts>

  <Concept uuid="ce2087fb-2aa3-467e-9cef-2eb8bd84f7b6" name="Object Typing">

   <Template ref="35a2e10e-20df-40f4-ab2f-dacf0a6744f4" />

   <TemplateRules operator="and">

    <TemplateRule Parameters="RelatingType[Type]=&apos;IfcCurtainWallType&apos;" />

   </TemplateRules>

  </Concept>

  <Concept uuid="b5ba858c-5aff-4329-99ba-98f88f4b4e03" name="Property Sets for Objects">

   <Template ref="f74255a6-0c0e-4f31-84ad-24981db62461" />

   <TemplateRules operator="and">

    <TemplateRule Parameters="PsetName[Value]=&apos;Pset_CurtainWallCommon&apos;" />

   </TemplateRules>

  </Concept>

  <Concept uuid="f5b84420-dccb-4951-ad5e-45a41a7a6a92" name="Quantity Sets">

   <Template ref="6652398e-6579-4460-8cb4-26295acfacc7" />

   <TemplateRules operator="and">

    <TemplateRule Parameters="QsetName[Value]=&apos;Qto_CurtainWallQuantities&apos;" />

   </TemplateRules>

  </Concept>

  <Concept uuid="7cbd5f96-fbd4-46ac-9544-0a0a00366214" name="Spatial Containment">

   <Template ref="d9a3f822-0014-4bc2-8d94-9d9067759045" />

   <TemplateRules operator="and">

    <TemplateRule Description="Default spatial container" Parameters="RelatingStructure[Type]=&apos;IfcBuildingStorey&apos;" />

    <TemplateRule Description="Spatial container for the element if it cannot be assigned to a building storey - curtain wall facades may be assigned directly to the building" Parameters="RelatingStructure[Type]=&apos;IfcBuilding&apos;" />

    <TemplateRule Description="Spatial container for the element in case that it is placed on site (outside of building)" Parameters="RelatingStructure[Type]=&apos;IfcSite&apos;" />

   </TemplateRules>

  </Concept>

  <Concept uuid="a0eae462-6143-4ff3-b911-fa81421ee96c" name="Placement">

   <Template ref="cbe85b5f-7912-4a43-8bb7-1e63bf40b26d" />

  </Concept>

  <Concept uuid="05ce60f3-e203-4c86-9eb3-ae9dba04e770" name="Axis 2D Geometry">

   <Template ref="782444e8-d681-475a-9034-a9e7f53c6d65" />

  </Concept>

 </Concepts>

</ConceptRoot>

Concept inheritance

#	Concept	Template	Model View
IfcRoot
	Identity	Software Identity	General Usage
	Revision Control	Revision Control	General Usage
IfcObjectDefinition
	Classification Association	Classification Association	General Usage
IfcObject
	Object User Identity	Object User Identity	General Usage
	Object Predefined Type	Object Predefined Type	General Usage
	Property Sets with Override	Property Sets with Override	General Usage
IfcProduct
	Product Placement	Product Placement	General Usage
	Product Geometric Representation	Product Geometric Representation	General Usage
IfcElement
	CoG Geometry	CoG Geometry	General Usage
	Box Geometry	Box Geometry	General Usage
	FootPrint Geometry	FootPrint Geometry	General Usage
	Body SurfaceOrSolidModel Geometry	Body SurfaceOrSolidModel Geometry	General Usage
	Body SurfaceModel Geometry	Body SurfaceModel Geometry	General Usage
	Body Tessellation Geometry	Body Tessellation Geometry	General Usage
	Body Brep Geometry	Body Brep Geometry	General Usage
	Body AdvancedBrep Geometry	Body AdvancedBrep Geometry	General Usage
	Body CSG Geometry	Body CSG Geometry	General Usage
	Mapped Geometry	Mapped Geometry	General Usage
	Element Voiding	Element Voiding	General Usage
	Element Projecting	Element Projecting	General Usage
	Linear Placement	Product Linear Placement	General Usage
IfcBuiltElement
	Product Assignment	Product Assignment	General Usage
	Surface 3D Geometry	Surface 3D Geometry	General Usage
IfcCurtainWall
	Object Typing	Object Typing	General Usage
	Property Sets for Objects	Property Sets for Objects	General Usage
	Quantity Sets	Quantity Sets	General Usage
	Spatial Containment	Spatial Containment	General Usage
	Placement	Product Local Placement	General Usage
	Axis 2D Geometry	Axis 2D Geometry	General Usage

Item	Change	Description
IFC2x3 to IFC4 4.0.0.0
IfcCurtainWall
OwnerHistory	MODIFIED	Instantiation changed to OPTIONAL.
PredefinedType	ADDED
IFC4x2 Candidate 4.2.0.0
IfcCurtainWall
PositionedRelativeTo	ADDED
IFC2x3 to IFC4 4.0.0.0
IfcCurtainWall
OwnerHistory	MODIFIED	Instantiation changed to OPTIONAL.
PredefinedType	ADDED
IFC4x2 Candidate 4.2.0.0
IfcCurtainWall
PositionedRelativeTo	ADDED

	Vorhangfassade
	Curtain Wall
	Mur rideau

IfcCurtainWall

Semantic definitions at the entity

Inherited definitions from supertypes

Definitions applying to General Usage

Formal representations