5.4.3.25 IfcOpeningElement

Ouverture
Öffnung

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. The relationship implies a Boolean subtraction operation between the volume of the voided element and the volume of the opening. It may be filled by an IfcDoor, IfcWindow, or another filling element by using the relationship IfcRelFillsElements.

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.

Containment Use Definition

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.

Common Use Definitions

The following concepts are inherited at supertypes:

 Instance diagram

Property Sets for Objects

The Property Sets for Objects concept applies to this entity as shown in Table 54.
PredefinedTypeName
 Pset_OpeningElementCommon
 Pset_Condition
 Pset_EnvironmentalImpactIndicators
 Pset_EnvironmentalImpactValues
 Pset_ManufacturerOccurrence
 Pset_ManufacturerTypeInformation
 Pset_PackingInstructions
 Pset_ServiceLife
 Pset_Warranty

Table 54 — IfcOpeningElement Property Sets for Objects



Quantity Sets

The Quantity Sets concept applies to this entity as shown in Table 55.
Name
Qto_OpeningElementBaseQuantities

Table 55 — IfcOpeningElement Quantity Sets



Element Filling

The Element Filling concept applies to this entity.



Product Placement

The Product Placement concept applies to this entity as shown in Table 56.
TypeRelativeDescription
IfcLocalPlacementIfcLocalPlacementRelative placement according to position and rotation relative to container.
IfcLocalPlacement Absolute placement according to position and rotation of world coordinate system.
IfcGridPlacement Placement according to grid intersection.

Table 56 — IfcOpeningElement Product 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 as shown in Table 57.
IdentifierTypeItems
   

Table 57 — IfcOpeningElement Body Geometry

Currently, the 'Body', and 'Box' representations are supported. The 'Box' representation includes the representation type 'BoundingBox' and is explained at IfcFeatureElement.

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 125 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 125 — Opening with full extrusion

Figure 126 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 126 — 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 127 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 127 — Opening with multiple extrusions




XSD 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: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 OF IfcRelFillsElement FOR RelatingOpeningElement;
END_ENTITY;

Link to EXPRESS-G diagram EXPRESS-G diagram

Attribute Definitions:

PredefinedType : 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.
HasFillings : 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.

Inheritance Graph:

ENTITY IfcOpeningElement
ENTITY IfcRoot
GlobalId : IfcGloballyUniqueId;
OwnerHistory : OPTIONAL IfcOwnerHistory;
Name : OPTIONAL IfcLabel;
Description : OPTIONAL IfcText;
ENTITY IfcObjectDefinition
INVERSE
HasAssignments : SET OF IfcRelAssigns FOR RelatedObjects;
Nests : SET [0:1] OF IfcRelNests FOR RelatedObjects;
IsNestedBy : SET OF IfcRelNests FOR RelatingObject;
HasContext : SET [0:1] OF IfcRelDeclares FOR RelatedDefinitions;
IsDecomposedBy : SET OF IfcRelAggregates FOR RelatingObject;
Decomposes : SET [0:1] OF IfcRelAggregates FOR RelatedObjects;
HasAssociations : SET OF IfcRelAssociates FOR RelatedObjects;
ENTITY IfcObject
ObjectType : OPTIONAL IfcLabel;
INVERSE
IsDeclaredBy : SET [0:1] OF IfcRelDefinesByObject FOR RelatedObjects;
Declares : SET OF IfcRelDefinesByObject FOR RelatingObject;
IsTypedBy : SET [0:1] OF IfcRelDefinesByType FOR RelatedObjects;
IsDefinedBy : SET OF IfcRelDefinesByProperties FOR RelatedObjects;
ENTITY IfcProduct
ObjectPlacement : OPTIONAL IfcObjectPlacement;
Representation : OPTIONAL IfcProductRepresentation;
INVERSE
ReferencedBy : SET OF IfcRelAssignsToProduct FOR RelatingProduct;
ENTITY IfcElement
Tag : OPTIONAL IfcIdentifier;
INVERSE
FillsVoids : SET [0:1] OF IfcRelFillsElement FOR RelatedBuildingElement;
ConnectedTo : SET OF IfcRelConnectsElements FOR RelatingElement;
IsInterferedByElements : SET OF IfcRelInterferesElements FOR RelatedElement;
InterferesElements : SET OF IfcRelInterferesElements FOR RelatingElement;
HasProjections : SET OF IfcRelProjectsElement FOR RelatingElement;
ReferencedInStructures : SET OF IfcRelReferencedInSpatialStructure FOR RelatedElements;
HasOpenings : SET OF IfcRelVoidsElement FOR RelatingBuildingElement;
IsConnectionRealization : SET OF IfcRelConnectsWithRealizingElements FOR RealizingElements;
ProvidesBoundaries : SET OF IfcRelSpaceBoundary FOR RelatedBuildingElement;
ConnectedFrom : SET OF IfcRelConnectsElements FOR RelatedElement;
ContainedInStructure : SET [0:1] OF IfcRelContainedInSpatialStructure FOR RelatedElements;
ENTITY IfcFeatureElement
ENTITY IfcFeatureElementSubtraction
INVERSE
VoidsElements : IfcRelVoidsElement FOR RelatedOpeningElement;
ENTITY IfcOpeningElement
PredefinedType : OPTIONAL IfcOpeningElementTypeEnum;
INVERSE
HasFillings : SET OF IfcRelFillsElement FOR RelatingOpeningElement;
END_ENTITY;

Examples:

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