IfcMember

Natural language names
deStab / Stabträger
enMember
frMembre
Change log
ItemSPFXMLChangeDescription
IFC2x3 to IFC4
    IfcMember
      OwnerHistoryMODIFIEDInstantiation changed to OPTIONAL.
      PredefinedTypeADDED
Semantic definitions at the entity
Entity definition

An IfcMember is a structural member designed to carry loads between or beyond points of support. It is not required to be load bearing. The orientation of the member (being horizontal, vertical or sloped) is not relevant to its definition (in contrary to IfcBeam and IfcColumn). An IfcMember represents a linear structural element from an architectural or structural modeling point of view and shall be used if it cannot be expressed more specifically as either an IfcBeam or an IfcColumn.

NOTE  The representation of a member in a structural analysis model is provided by IfcStructuralCurveMember being part of an IfcStructuralAnalysisModel.

The IFC specification provides two entities for member occurrences:

HISTORY  New entity in IFC2x2 Addendum 1.
Attribute definitions
#AttributeTypeCardinalityDescription C
9PredefinedTypeIfcMemberTypeEnum[0:1] Predefined generic type for a member that is specified in an enumeration. There may be a property set given for the predefined types.
NOTE  The PredefinedType shall only be used, if no IfcMemberType is assigned, providing its own IfcMemberType.PredefinedType.
X
Formal Propositions
RuleDescription
CorrectPredefinedTypeEither the PredefinedType attribute is unset (e.g. because an IfcMemberType is associated), or the inherited attribute ObjectType shall be provided, if the PredefinedType is set to USERDEFINED.
CorrectTypeAssignedEither there is no member type object associated, i.e. the IsTypedBy inverse relationship is not provided, or the associated type object has to be of type IfcMemberType.
Inherited definitions from supertypes
Entity inheritance IfcMemberStandardCase IfcBuildingElement IfcElement IfcProduct IfcObject IfcObjectDefinition IfcRoot
Attribute inheritance
#AttributeTypeCardinalityDescriptionC
IfcRoot
1GlobalIdIfcGloballyUniqueId[1:1] Assignment of a globally unique identifier within the entire software world. X
2OwnerHistoryIfcOwnerHistory[0:1] 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.
X
3NameIfcLabel[0:1] 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[0:1] 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). 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). 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. 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). 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). 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[0:1] 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. 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. 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. 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. X
IfcProduct
6ObjectPlacementIfcObjectPlacement[0:1] 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[0:1] 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
IfcElement
8TagIfcIdentifier[0:1] 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.
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.
X
HasProjectionsIfcRelProjectsElement
@RelatingElement
S[0:?]Projection relationship that adds a feature (using a Boolean union) to the IfcBuildingElement.X
ReferencedInStructuresIfcRelReferencedInSpatialStructure
@RelatedElements
S[0:?]Reference relationship to the spatial structure element, to which the element is additionally associated. This relationship may not be hierarchical, an element may be referenced by zero, one or many spatial structure elements. 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
IfcBuildingElement
IfcMember
9PredefinedTypeIfcMemberTypeEnum[0:1] Predefined generic type for a member that is specified in an enumeration. There may be a property set given for the predefined types.
NOTE  The PredefinedType shall only be used, if no IfcMemberType is assigned, providing its own IfcMemberType.PredefinedType.
X
Definitions applying to Common Use Definitions

 Instance diagram


Concept usage

Object Typing

The Object Typing concept applies to this entity as shown in Table 125.

Type
IfcMemberType

Table 125 — IfcMember Object Typing



Property Sets for Objects

The Property Sets for Objects concept applies to this entity as shown in Table 126.

PredefinedTypeNameProperties
 Pset_MemberCommonSingle Value
NameValue
ReferenceIfcIdentifier
SpanIfcPositiveLengthMeasure
SlopeIfcPlaneAngleMeasure
RollIfcPlaneAngleMeasure
IsExternalIfcBoolean
ThermalTransmittanceIfcThermalTransmittanceMeasure
LoadBearingIfcBoolean
FireRatingIfcLabel
Enumerated Value
NameValueValue
StatusIfcLabelIfcLabel
 Pset_ConcreteElementGeneralSingle Value
NameValue
ConstructionMethodIfcLabel
StructuralClassIfcLabel
StrengthClassIfcLabel
ExposureClassIfcLabel
ReinforcementVolumeRatioIfcMassDensityMeasure
ReinforcementAreaRatioIfcAreaDensityMeasure
DimensionalAccuracyClassIfcLabel
ConstructionToleranceClassIfcLabel
ConcreteCoverIfcPositiveLengthMeasure
ConcreteCoverAtMainBarsIfcPositiveLengthMeasure
ConcreteCoverAtLinksIfcPositiveLengthMeasure
ReinforcementStrengthClassIfcLabel
 Pset_PrecastConcreteElementFabricationSingle Value
NameValue
TypeDesignatorIfcLabel
ProductionLotIdIfcIdentifier
SerialNumberIfcIdentifier
PieceMarkIfcLabel
AsBuiltLocationNumberIfcLabel
ActualProductionDateIfcDateTime
ActualErectionDateIfcDateTime
 Pset_PrecastConcreteElementGeneralSingle Value
NameValue
TypeDesignatorIfcLabel
CornerChamferIfcPositiveLengthMeasure
ManufacturingToleranceClassIfcLabel
FormStrippingStrengthIfcPressureMeasure
LiftingStrengthIfcPressureMeasure
ReleaseStrengthIfcPressureMeasure
MinimumAllowableSupportLengthIfcPositiveLengthMeasure
InitialTensionIfcPressureMeasure
TendonRelaxationIfcPositiveRatioMeasure
TransportationStrengthIfcPressureMeasure
SupportDuringTransportDescriptionIfcText
HollowCorePluggingIfcLabel
CamberAtMidspanIfcRatioMeasure
BatterAtStartIfcPlaneAngleMeasure
BatterAtEndIfcPlaneAngleMeasure
TwistingIfcPlaneAngleMeasure
ShorteningIfcRatioMeasure
PieceMarkIfcLabel
DesignLocationNumberIfcLabel
 Pset_EnvironmentalImpactIndicatorsSingle Value
NameValue
ReferenceIfcIdentifier
FunctionalUnitReferenceIfcLabel
UnitIfcText
ExpectedServiceLifeIfcTimeMeasure
TotalPrimaryEnergyConsumptionPerUnitIfcEnergyMeasure
WaterConsumptionPerUnitIfcVolumeMeasure
HazardousWastePerUnitIfcMassMeasure
NonHazardousWastePerUnitIfcMassMeasure
ClimateChangePerUnitIfcMassMeasure
AtmosphericAcidificationPerUnitIfcMassMeasure
RenewableEnergyConsumptionPerUnitIfcEnergyMeasure
NonRenewableEnergyConsumptionPerUnitIfcEnergyMeasure
ResourceDepletionPerUnitIfcMassMeasure
InertWastePerUnitIfcMassMeasure
RadioactiveWastePerUnitIfcMassMeasure
StratosphericOzoneLayerDestructionPerUnitIfcMassMeasure
PhotochemicalOzoneFormationPerUnitIfcMassMeasure
EutrophicationPerUnitIfcMassMeasure
Enumerated Value
NameValueValue
LifeCyclePhaseIfcLabelIfcLabel
 Pset_EnvironmentalImpactValuesSingle Value
NameValue
TotalPrimaryEnergyConsumptionIfcEnergyMeasure
WaterConsumptionIfcVolumeMeasure
HazardousWasteIfcMassMeasure
NonHazardousWasteIfcMassMeasure
ClimateChangeIfcMassMeasure
AtmosphericAcidificationIfcMassMeasure
RenewableEnergyConsumptionIfcEnergyMeasure
NonRenewableEnergyConsumptionIfcEnergyMeasure
ResourceDepletionIfcMassMeasure
InertWasteIfcMassMeasure
RadioactiveWasteIfcMassMeasure
StratosphericOzoneLayerDestructionIfcMassMeasure
PhotochemicalOzoneFormationIfcMassMeasure
EutrophicationIfcMassMeasure
LeadInTimeIfcDuration
DurationIfcDuration
LeadOutTime 
 Pset_ConditionSingle Value
NameValue
AssessmentDateIfcDate
AssessmentConditionIfcLabel
AssessmentDescriptionIfcText
 Pset_ManufacturerOccurrenceSingle Value
NameValue
AcquisitionDateIfcDate
BarCodeIfcIdentifier
SerialNumberIfcIdentifier
BatchReferenceIfcIdentifier
Enumerated Value
NameValueValue
AssemblyPlaceIfcLabelIfcLabel
 Pset_ManufacturerTypeInformationSingle Value
NameValue
GlobalTradeItemNumberIfcIdentifier
ArticleNumberIfcIdentifier
ModelReferenceIfcLabel
ModelLabelIfcLabel
ManufacturerIfcLabel
ProductionYearIfcLabel
Enumerated Value
NameValueValue
AssemblyPlaceIfcLabelIfcLabel
 Pset_ServiceLifeSingle Value
NameValue
MeanTimeBetweenFailureIfcDuration
Bounded Value
NameValueValue
ServiceLifeDurationIfcDurationIfcDuration
 Pset_WarrantySingle Value
NameValue
WarrantyIdentifierIfcIdentifier
WarrantyStartDateIfcDate
WarrantyEndDateIfcDate
IsExtendedWarrantyIfcBoolean
WarrantyPeriodIfcTimeMeasure
WarrantyContentIfcText
ExclusionsIfcText

Table 126 — IfcMember Property Sets for Objects



Quantity Sets

The Quantity Sets concept applies to this entity as shown in Table 127.

Name
Qto_MemberBaseQuantities

Table 127 — IfcMember Quantity Sets



Material Profile Set

The Material Profile Set concept applies to this entity.

The material of the IfcMember is defined by the IfcMaterialProfileSet or as fallback by IfcMaterial, and it is attached either directly or at the IfcMemberType.

NOTE  It is illegal to assign an IfcMaterialProfileSetUsage to an IfcMember. Only the subtype IfcMemberStandardCase supports this concept.


Spatial Containment

The Spatial Containment concept applies to this entity as shown in Table 128.

StructureDescription
IfcBuildingStoreyDefault spatial container
IfcBuildingSpatial container for the element if it cannot be assigned to a building storey
IfcSiteSpatial container for the element in case that it is placed on site (outside of building)

Table 128 — IfcMember Spatial Containment

The IfcMember, as any subtype of IfcBuildingElement, may participate alternatively in one of the two different containment relationships:

  • the Spatial Containment (defined here), or
  • the Element Composition.


Axis 3D Geometry

The Axis 3D Geometry concept applies to this entity as shown in Table 129.

IdentifierTypeItemsDescription
AxisCurve3DIfcBoundedCurveThree-dimensional reference curve for the member.

Table 129 — IfcMember Axis 3D Geometry

The axis representation can be used to represent the system length of a member that may extent the body length of the member.

NOTE  The 'Axis' is not used to locate the material profile set, only the subtype IfcMemberStandardCase provides this capability.


Body SweptSolid Geometry

The Body SweptSolid Geometry concept applies to this entity.

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

Figure 212 illustrates a 'SweptSolid' geometric representation. There are no restrictions or conventions on how to use the local placement (black), solid of extrusion placement (red) and profile placement (green).

standard member

Figure 212 — Member swept solid



Body AdvancedSweptSolid Geometry

The Body AdvancedSweptSolid Geometry concept applies to this entity.

The following additional constraints apply to the 'AdvancedSweptSolid' representation type:

MappedRepresentation Representation Type



Body Clipping Geometry

The Body Clipping Geometry concept applies to this entity.

The following constraints apply to the 'Clipping' representation:

  • Solid: see 'SweptSolid' geometric representation
  • Profile: see 'SweptSolid' geometric representation
  • Extrusion: see 'SweptSolid' geometric representation
  • Boolean result: The IfcBooleanClippingResult shall be supported, allowing for Boolean differences between the swept solid (here IfcExtrudedAreaSolid) and one or several IfcHalfSpaceSolid (or its subtypes).

Figure 213 illustrates a 'Clipping' geometric representation with use of IfcBooleanClippingResult between an IfcExtrudedAreaSolid and an IfcHalfSpaceSolid to create a clipped body.

clipped member

Figure 213 — Member clipping



Product Assignment

The Product Assignment concept applies to this entity as shown in Table 130.

TypeDescription
IfcStructuralCurveMemberAn idealized structural member corresponding to the member.
IfcTaskA task for operating on the member.

Table 130 — IfcMember Product Assignment



Concept inheritance

#ConceptModel View
IfcRoot
Software IdentityCommon Use Definitions
Revision ControlCommon Use Definitions
IfcObject
Object Occurrence Predefined TypeCommon Use Definitions
IfcElement
Product Local PlacementCommon Use Definitions
Box GeometryCommon Use Definitions
FootPrint GeometryCommon Use Definitions
Body SurfaceOrSolidModel GeometryCommon Use Definitions
Body SurfaceModel GeometryCommon Use Definitions
Body Tessellation GeometryCommon Use Definitions
Body Brep GeometryCommon Use Definitions
Body AdvancedBrep GeometryCommon Use Definitions
Body CSG GeometryCommon Use Definitions
Mapped GeometryCommon Use Definitions
Mesh GeometryCommon Use Definitions
IfcBuildingElement
Surface 3D GeometryCommon Use Definitions
IfcMember
Object TypingCommon Use Definitions
Property Sets for ObjectsCommon Use Definitions
Quantity SetsCommon Use Definitions
Material Profile SetCommon Use Definitions
Spatial ContainmentCommon Use Definitions
Axis 3D GeometryCommon Use Definitions
Body SweptSolid GeometryCommon Use Definitions
Body AdvancedSweptSolid GeometryCommon Use Definitions
Body Clipping GeometryCommon Use Definitions
Product AssignmentCommon Use Definitions
Formal representations
XSD Specification
 <xs:element name="IfcMember" type="ifc:IfcMember" substitutionGroup="ifc:IfcBuildingElement" nillable="true"/>
 <xs:complexType name="IfcMember">
  <xs:complexContent>
   <xs:extension base="ifc:IfcBuildingElement">
    <xs:attribute name="PredefinedType" type="ifc:IfcMemberTypeEnum" use="optional"/>
   </xs:extension>
  </xs:complexContent>
 </xs:complexType>
EXPRESS Specification
ENTITY IfcMember
 SUPERTYPE OF(IfcMemberStandardCase)
 SUBTYPE OF (IfcBuildingElement);
  PredefinedType : OPTIONAL IfcMemberTypeEnum;
 WHERE
  CorrectPredefinedType : NOT(EXISTS(PredefinedType)) OR (PredefinedType <> IfcMemberTypeEnum.USERDEFINED) OR ((PredefinedType = IfcMemberTypeEnum.USERDEFINED) AND EXISTS (SELF\IfcObject.ObjectType));
  CorrectTypeAssigned : (SIZEOF(IsTypedBy) = 0) OR ('IFCSHAREDBLDGELEMENTS.IFCMEMBERTYPE' IN TYPEOF(SELF\IfcObject.IsTypedBy[1].RelatingType));
END_ENTITY;

Link to EXPRESS-G diagram EXPRESS-G diagram

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