IfcOpeningElement

Natural language names
Öffnung
Opening Element
Ouverture
Change log
ItemSPFXMLChangeDescription
IFC2x3 to IFC4 4.0.0.0
    IfcOpeningElement
      OwnerHistoryMODIFIEDInstantiation changed to OPTIONAL.
      PredefinedTypeADDED
IFC4 Addendum 1 4.0.1.0
    IfcOpeningElement
      HasCoveringsADDED
IFC4.2 Candidate 4.2.0.0
    IfcOpeningElement
      PositionedRelativeToADDED
Semantic definitions at the entity
Entity definition

The opening element stands for opening, recess or chase, all reflecting voids. It represents a void within any element that has physical manifestation. Openings can be inserted into walls, slabs, beams, columns, or other elements.

The IFC specification provides two entities for opening elements:

NOTE  View definitions or implementer agreements may restrict the types of elements which can be voided by an IfcOpeningElement or IfcOpeningStandardCase

There are two different types of opening elements:

The attribute PredefinedType should be used to capture the differences,

An IfcOpeningElement has to be inserted into an IfcElement by using the IfcRelVoidsElement relationship. It may be filled by an IfcDoor, IfcWindow, or another filling element by using the relationship IfcRelFillsElements. Depending on the type of the IfcShapeRepresentation of the IfcOpeningElement the voiding relationship implies:

The IfcOpeningElement shall not participate in the containment relationship, i.e. it is not linked directly to the spatial structure of the project. It has a mandatory VoidsElements inverse relationship pointing to the IfcElement that is contained in the spatial structure.

NOTE  See IfcRelVoidsElement for a diagram on how to apply spatial containment and the voiding relationship.

HISTORY  New entity in IFC1.0

IFC2x CHANGE  The intermediate ABSTRACT supertypes IfcFeatureElement and IfcFeatureSubtraction have been added.

IFC4 CHANGE  The attribute PredefinedType has been added at the end of attribute list. It should be used instead of the inherited attribute ObjectType from now on.

Attribute definitions
#AttributeTypeCardinalityDescription G
9PredefinedTypeIfcOpeningElementTypeEnum? Predefined generic type for an opening that is specified in an enumeration. There may be a property set given specificly for the predefined types.
IFC4 CHANGE The attribute has been added at the end of the entity definition.
X
HasFillingsIfcRelFillsElement
@RelatingOpeningElement
S[0:?]Reference to the Filling Relationship that is used to assign Elements as Fillings for this Opening Element. The Opening Element can be filled with zero-to-many Elements. X
Inherited definitions from supertypes
Entity inheritance IfcOpeningStandardCase IfcFeatureElementSubtraction IfcFeatureElement IfcElement IfcProduct IfcObject IfcObjectDefinition 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
IfcObjectDefinition
HasAssignmentsIfcRelAssigns
@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
NestsIfcRelNests
@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
IsNestedByIfcRelNests
@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
HasContextIfcRelDeclares
@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
IsDecomposedByIfcRelAggregates
@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
DecomposesIfcRelAggregates
@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
HasAssociationsIfcRelAssociates
@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
5ObjectTypeIfcLabel? 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
IsDeclaredByIfcRelDefinesByObject
@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
DeclaresIfcRelDefinesByObject
@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
IsTypedByIfcRelDefinesByType
@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
IsDefinedByIfcRelDefinesByProperties
@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
6ObjectPlacementIfcObjectPlacement? 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
7RepresentationIfcProductRepresentation? 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
ReferencedByIfcRelAssignsToProduct
@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
PositionedRelativeToIfcRelPositions
@RelatedProducts
S[0:1]X
ReferencedInStructuresIfcRelReferencedInSpatialStructure
@RelatedElements
S[0:?]X
IfcElement
8TagIfcIdentifier? 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
FillsVoidsIfcRelFillsElement
@RelatedBuildingElement
S[0:1]Reference to the IfcRelFillsElement Relationship that puts the element as a filling into the opening created within another element. X
ConnectedToIfcRelConnectsElements
@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
IsInterferedByElementsIfcRelInterferesElements
@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
InterferesElementsIfcRelInterferesElements
@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
HasProjectionsIfcRelProjectsElement
@RelatingElement
S[0:?]Projection relationship that adds a feature (using a Boolean union) to the IfcBuildingElement. X
HasOpeningsIfcRelVoidsElement
@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
IsConnectionRealizationIfcRelConnectsWithRealizingElements
@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
ProvidesBoundariesIfcRelSpaceBoundary
@RelatedBuildingElement
S[0:?]Reference to space boundaries by virtue of the objectified relationship IfcRelSpaceBoundary. It defines the concept of an element bounding spaces. X
ConnectedFromIfcRelConnectsElements
@RelatedElement
S[0:?]Reference to the element connection relationship. The relationship then refers to the other element that is connected to this element. X
ContainedInStructureIfcRelContainedInSpatialStructure
@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
HasCoveringsIfcRelCoversBldgElements
@RelatingBuildingElement
S[0:?]Reference to IfcCovering by virtue of the objectified relationship IfcRelCoversBldgElement. It defines the concept of an element having coverings associated. X
IfcFeatureElement
IfcFeatureElementSubtraction
VoidsElementsIfcRelVoidsElement
@RelatedOpeningElement
Reference to the Voids Relationship that uses this Opening Element to create a void within an Element. The Opening Element can only be used to create a single void within a single Element. X
IfcOpeningElement
9PredefinedTypeIfcOpeningElementTypeEnum? Predefined generic type for an opening that is specified in an enumeration. There may be a property set given specificly for the predefined types.
IFC4 CHANGE The attribute has been added at the end of the entity definition.
X
HasFillingsIfcRelFillsElement
@RelatingOpeningElement
S[0:?]Reference to the Filling Relationship that is used to assign Elements as Fillings for this Opening Element. The Opening Element can be filled with zero-to-many Elements. X
Definitions applying to General Usage

 Instance diagram


Concept usage

Property Sets for Objects

The Property Sets for Objects concept template applies to this entity as shown in Table 69.

PsetNameProperties
Pset_OpeningElementCommon
TemplatePropertyNameValueReference
Single ValueReferenceIfcIdentifier
Enumerated ValueStatusIfcLabelPEnum_ElementStatus
Single ValuePurposeIfcLabel
Single ValueFireExitIfcBoolean
Single ValueProtectedOpeningIfcBoolean

Table 69 — IfcOpeningElement Property Sets for Objects



Quantity Sets

The Quantity Sets concept template applies to this entity as shown in Table 70.

QsetNameQuantities
Qto_OpeningElementBaseQuantities
TemplateQuantityNameLengthValueAreaValueVolumeValue
Length QuantityWidth
Length QuantityHeight
Length QuantityDepth
Area QuantityArea
Volume QuantityVolume

Table 70 — IfcOpeningElement Quantity Sets



Product Local Placement

The Product Local Placement concept template applies to this entity as shown in Table 71.

Table 71 — IfcOpeningElement Product Local Placement

The local placement for IfcOpeningElement is defined in its supertype IfcProduct. It is defined by the IfcLocalPlacement, which defines the local coordinate system that is referenced by all geometric representations.



Body Geometry

The Body Geometry concept applies to this entity.

The 'Body' representation of IfcOpeningElement can be represented using the representation types 'SweptSolid', and 'Brep'. The representation type 'Brep' is explained at IfcFeatureElement

Swept Solid Representation Type with Horizontal Extrusion

The 'SweptSolid' geometric representation of IfcOpeningElement, using horizontal extrusion direction (for walls), is defined using the swept area solid geometry. The following attribute values for the IfcShapeRepresentation holding this geometric representation shall be used:

The following additional constraints apply to the swept solid representation:

NOTE  In case of non-parallel jambs, the shape representation shall be a 'SweptSolid' representation with vertical extrusion.

Figure 159 illustrates an opening with horizontal extrusion.

NOTE  The local placement directions for the IfcOpeningElement are only given as an example, other directions are valid as well.

"standard opening"

Figure 159 — Opening with full extrusion

Figure 160 illustrates an opening for a recess.

NOTE  The local placement directions for the IfcOpeningElement are only given as an example, other directions are valid as well.

NOTE  Rectangles are now defined centric, the placement location has to be set:

"recess"

Figure 160 — Opening with recess extrusion

Swept Solid Representation with Vertical Extrusion

The 'SweptSolid' geometric representation of IfcOpeningElement, using vertical extrusion direction (for walls), is defined using the swept area solid geometry, however the extrusion direction may be vertical, i.e. in case of a wall opening, the extrusion would be in the direction of the wall height. The following attribute values for the IfcShapeRepresentation holding this geometric representation shall be used:

The following additional constraints apply to the swept solid representation:

Vertical extrusions shall be used when an opening or recess has a non rectangular foot print geometry that does not change along the height of the opening or recess.

Figure 161 shows a vertical extrusion with multiple extrusion bodies for the opening. Each extrusion body has a different extrusion lenght.

NOTE  The local placement directions for the IfcOpeningElement are only given as an example, other directions are valid as well.

"vertical extrusion"

Figure 161 — Opening with multiple extrusions



Reference Geometry

The Reference Geometry concept applies to this entity.

Since there are no Boolean operations, either as IfcBooleanResult or implicitly by IfcRelVoidsElement the geometry of the IfcOpeningElement shall not be used to subtract the opening from the 'Body' shape representation of the voided element.



mvdXML Specification
<?xml version="1.0" encoding="utf-8"?>
<ConceptRoot xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" uuid="2b58c57e-3ac1-4d90-b3f0-ac2daac69ed7" name="IfcOpeningElement" applicableRootEntity="IfcOpeningElement">
 <Applicability>
  <Template ref="aead99d1-e4e5-487d-948c-3780dd5079a2" />
  <TemplateRules operator="and">
  </TemplateRules>
 </Applicability>
 <Concepts>
  <Concept uuid="84c422e2-81be-487f-986c-a528195940c9" name="Property Sets for Objects" override="true">
   <Template ref="f74255a6-0c0e-4f31-84ad-24981db62461" />
   <TemplateRules operator="and">
    <TemplateRule Parameters="PsetName[Value]=&apos;Pset_OpeningElementCommon&apos;" />
   </TemplateRules>
  </Concept>
  <Concept uuid="cb4e8bac-821e-44e8-9d22-e77b021736b1" name="Quantity Sets">
   <Template ref="6652398e-6579-4460-8cb4-26295acfacc7" />
   <TemplateRules operator="and">
    <TemplateRule Parameters="QsetName[Value]=&apos;Qto_OpeningElementBaseQuantities&apos;" />
   </TemplateRules>
  </Concept>
  <Concept uuid="c3fa5292-4e42-44fa-ba31-e6444ae13ed0" name="Product Local Placement">
   <Template ref="cbe85b5f-7912-4a43-8bb7-1e63bf40b26d" />
  </Concept>
  <Concept uuid="f55ff4eb-9d4d-4329-9c16-3b7f60901a2b" name="Body Geometry">
   <Template ref="c446bd16-2de3-4b97-b34f-4446ac0badc2" />
  </Concept>
  <Concept uuid="c84c3c3f-8873-4653-a768-9b4f85380634" name="Reference Geometry">
   <Template ref="d68f9f1b-223a-4a8a-912b-b83f032a74f2" />
  </Concept>
 </Concepts>
</ConceptRoot>
Concept inheritance

#ConceptTemplateModel View
IfcRoot
IdentitySoftware IdentityGeneral Usage
Revision ControlRevision ControlGeneral Usage
IfcObjectDefinition
Classification AssociationClassification AssociationGeneral Usage
IfcObject
Object User IdentityObject User IdentityGeneral Usage
Object Predefined TypeObject Predefined TypeGeneral Usage
Object TypingObject TypingGeneral Usage
Property Sets with OverrideProperty Sets with OverrideGeneral Usage
IfcProduct
Product PlacementProduct PlacementGeneral Usage
Product Geometric RepresentationProduct Geometric RepresentationGeneral Usage
IfcElement
CoG GeometryCoG GeometryGeneral Usage
Box GeometryBox GeometryGeneral Usage
FootPrint GeometryFootPrint GeometryGeneral Usage
Body SurfaceOrSolidModel GeometryBody SurfaceOrSolidModel GeometryGeneral Usage
Body SurfaceModel GeometryBody SurfaceModel GeometryGeneral Usage
Body Tessellation GeometryBody Tessellation GeometryGeneral Usage
Body Brep GeometryBody Brep GeometryGeneral Usage
Body AdvancedBrep GeometryBody AdvancedBrep GeometryGeneral Usage
Body CSG GeometryBody CSG GeometryGeneral Usage
Mapped GeometryMapped GeometryGeneral Usage
Element VoidingElement VoidingGeneral Usage
Element ProjectingElement ProjectingGeneral Usage
Linear PlacementProduct Linear PlacementGeneral Usage
IfcFeatureElement
Spatial ContainmentSpatial ContainmentGeneral Usage
IfcOpeningElement
Property Sets for ObjectsProperty Sets for ObjectsGeneral Usage
Quantity SetsQuantity SetsGeneral Usage
Product Local PlacementProduct Local PlacementGeneral Usage
Body GeometryBody GeometryGeneral Usage
Reference GeometryReference GeometryGeneral Usage
Formal representations
XML Specification
 <xs:element name="IfcOpeningElement" type="ifc:IfcOpeningElement" substitutionGroup="ifc:IfcFeatureElementSubtraction" nillable="true"/>
 <xs:complexType name="IfcOpeningElement">
  <xs:complexContent>
   <xs:extension base="ifc:IfcFeatureElementSubtraction">
    <xs:sequence>
     <xs:element name="HasFillings" type="ifc:IfcRelFillsElement" nillable="true" minOccurs="0" maxOccurs="1"/>
    </xs:sequence>
    <xs:attribute name="PredefinedType" type="ifc:IfcOpeningElementTypeEnum" use="optional"/>
   </xs:extension>
  </xs:complexContent>
 </xs:complexType>
EXPRESS Specification
ENTITY IfcOpeningElement
 SUPERTYPE OF(IfcOpeningStandardCase)
 SUBTYPE OF (IfcFeatureElementSubtraction);
  PredefinedType : OPTIONAL IfcOpeningElementTypeEnum;
 INVERSE
  HasFillings : SET [0:?] OF IfcRelFillsElement FOR RelatingOpeningElement;
END_ENTITY;

Link to EXPRESS-G diagram EXPRESS-G diagram

References  References: IfcRelFillsElement

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