IFC 4.3.2.20250123 (IFC4X3_ADD2) under development

6.1.3.18 IfcMember

6.1.3.18.1 Semantic 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.

There are two main representations for member occurrences:

  • IfcMember with IfcMaterialProfileSetUsage is used for all occurrences of members, that have a profile defined that is swept along a directrix. The profile might be changed uniformly by a taper definition along the directrix. The profile parameter and its cardinal point of insertion can be fully described by the IfcMaterialProfileSetUsage. These members are always represented geometricly by an 'Axis' and a 'SweptSolid' or 'AdvancedSweptSolid' shape representation (or by a 'Clipping' geometry based on the swept solid), if a 3D geometric representation is assigned.
  • IfcMember without IfcMaterialProfileSetUsage is used for all other occurrences of members, particularly for members with changing profile sizes along the extrusion, or members defined by non-linear extrusion, or members having only 'Brep', or 'SurfaceModel' geometry, or if a more parametric representation is not intended.

6.1.3.18.2 Entity inheritance

6.1.3.18.3 Attributes

# Attribute Type Description
IfcRoot (4)
IfcObjectDefinition (7)
IfcObject (5)
IfcProduct (5)
IfcElement (13)
Click to show 34 hidden inherited attributes
IfcMember (1)
9 PredefinedType OPTIONAL IfcMemberTypeEnum

Predefined generic type for a member that is specified in an enumeration. There may be a property set given for the predefined types.

Table 6.1.3.18.J

6.1.3.18.4 Formal propositions

Name Description
CorrectPredefinedType

Either 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.

NOT(EXISTS(PredefinedType)) OR
(PredefinedType <> IfcMemberTypeEnum.USERDEFINED) OR
((PredefinedType = IfcMemberTypeEnum.USERDEFINED) AND EXISTS (SELF\IfcObject.ObjectType))
CorrectTypeAssigned

Either 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.

(SIZEOF(IsTypedBy) = 0) OR
('IFC4X3_DEV_54a9de1b.IFCMEMBERTYPE' IN TYPEOF(SELF\IfcObject.IsTypedBy[1].RelatingType))
Table 6.1.3.18.K

6.1.3.18.5 Property sets

  • Pset_ConcreteElementGeneral
    • AssemblyPlace
    • CastingMethod
    • StructuralClass
    • StrengthClass
    • ExposureClass
    • ReinforcementVolumeRatio
    • ReinforcementAreaRatio
    • DimensionalAccuracyClass
    • ConstructionToleranceClass
    • ConcreteCover
    • ConcreteCoverAtMainBars
    • ConcreteCoverAtLinks
    • ReinforcementStrengthClass
  • Pset_Condition
    • AssessmentDate
    • AssessmentCondition
    • AssessmentDescription
    • AssessmentType
    • AssessmentMethod
    • LastAssessmentReport
    • NextAssessmentDate
    • AssessmentFrequency
  • Pset_ConstructionAdministration
    • ProcurementMethod
    • SpecificationSectionNumber
    • SubmittalIdentifer
  • Pset_ConstructionOccurence
    • InstallationDate
    • ModelNumber
    • TagNumber
    • AssetIdentifier
  • Pset_DoorLiningProperties
    • LiningDepth
    • LiningThickness
    • ThresholdDepth
    • ThresholdThickness
    • TransomThickness
    • TransomOffset
    • LiningOffset
    • ThresholdOffset
    • CasingThickness
    • CasingDepth
    • LiningToPanelOffsetX
    • LiningToPanelOffsetY
  • Pset_ElementKinematics
    • CyclicPath
    • CyclicRange
    • LinearPath
    • LinearRange
    • MaximumAngularVelocity
    • MaximumConstantSpeed
    • MinimumTime
  • Pset_EnvironmentalCondition
    • ReferenceAirRelativeHumidity
    • ReferenceEnvironmentTemperature
    • MaximumAtmosphericPressure
    • StorageTemperatureRange
    • MaximumWindSpeed
    • OperationalTemperatureRange
    • MaximumRainIntensity
    • SaltMistLevel
    • SeismicResistance
    • SmokeLevel
    • MaximumSolarRadiation
  • Pset_EnvironmentalImpactIndicators
    • Reference
    • FunctionalUnitReference
    • IndicatorsUnit
    • LifeCyclePhase
    • ExpectedServiceLife
    • TotalPrimaryEnergyConsumptionPerUnit
    • WaterConsumptionPerUnit
    • HazardousWastePerUnit
    • NonHazardousWastePerUnit
    • ClimateChangePerUnit
    • AtmosphericAcidificationPerUnit
    • RenewableEnergyConsumptionPerUnit
    • NonRenewableEnergyConsumptionPerUnit
    • ResourceDepletionPerUnit
    • InertWastePerUnit
    • RadioactiveWastePerUnit
    • StratosphericOzoneLayerDestructionPerUnit
    • PhotochemicalOzoneFormationPerUnit
    • EutrophicationPerUnit
  • Pset_EnvironmentalImpactValues
    • TotalPrimaryEnergyConsumption
    • WaterConsumption
    • HazardousWaste
    • NonHazardousWaste
    • ClimateChange
    • AtmosphericAcidification
    • RenewableEnergyConsumption
    • NonRenewableEnergyConsumption
    • ResourceDepletion
    • InertWaste
    • RadioactiveWaste
    • StratosphericOzoneLayerDestruction
    • PhotochemicalOzoneFormation
    • Eutrophication
    • LeadInTime
    • Duration
    • LeadOutTime
  • Pset_InstallationOccurrence
    • InstallationDate
    • AcceptanceDate
    • PutIntoOperationDate
  • Pset_MaintenanceStrategy
    • AssetCriticality
    • AssetFrailty
    • AssetPriority
    • MonitoringType
    • AccidentResponse
  • Pset_MaintenanceTriggerCondition
    • ConditionTargetPerformance
    • ConditionMaintenanceLevel
    • ConditionReplacementLevel
    • ConditionDisposalLevel
  • Pset_MaintenanceTriggerDuration
    • DurationTargetPerformance
    • DurationMaintenanceLevel
    • DurationReplacementLevel
    • DurationDisposalLevel
  • Pset_MaintenanceTriggerPerformance
    • TargetPerformance
    • PerformanceMaintenanceLevel
    • ReplacementLevel
    • DisposalLevel
  • Pset_ManufacturerOccurrence
    • AcquisitionDate
    • BarCode
    • SerialNumber
    • BatchReference
    • AssemblyPlace
    • ManufacturingDate
  • Pset_ManufacturerTypeInformation
    • GlobalTradeItemNumber
    • ArticleNumber
    • ModelReference
    • ModelLabel
    • Manufacturer
    • ProductionYear
    • AssemblyPlace
    • OperationalDocument
    • SafetyDocument
    • PerformanceCertificate
  • Pset_MemberCommon
    • Reference
    • Status
    • Span
    • Slope
    • Roll
    • IsExternal
    • ThermalTransmittance
    • LoadBearing
    • FireRating
  • Pset_MemberTypeAnchoringBar BRACE
    • MechanicalStressType
    • HasLightningRod
  • Pset_MemberTypeCatenaryStay STAY_CABLE
    • AssemblyInstruction
    • NominalLength
    • CatenaryStayType
    • NominalHeight
  • Pset_MemberTypeOCSRigidSupport MEMBER
    • AssemblyInstruction
    • ContactWireStagger
  • Pset_MemberTypePost POST
    • NominalHeight
    • ConicityRatio
    • LoadBearingCapacity
    • WindLoadRating
    • TorsionalStrength
    • BendingStrength
  • Pset_MemberTypeTieBar TIEBAR
    • IsTemporaryInstallation
  • Pset_PermeableCoveringProperties
    • OperationType
    • PanelPosition
    • FrameDepth
    • FrameThickness
  • Pset_PrecastConcreteElementFabrication
    • TypeDesignation
    • ProductionLotId
    • SerialNumber
    • PieceMark
    • AsBuiltLocationNumber
    • ActualProductionDate
    • ActualErectionDate
  • Pset_PrecastConcreteElementGeneral
    • TypeDesignation
    • CornerChamfer
    • ManufacturingToleranceClass
    • FormStrippingStrength
    • LiftingStrength
    • ReleaseStrength
    • MinimumAllowableSupportLength
    • InitialTension
    • TendonRelaxation
    • TransportationStrength
    • SupportDuringTransportDescription
    • SupportDuringTransportDocReference
    • HollowCorePlugging
    • CamberAtMidspan
    • BatterAtStart
    • BatterAtEnd
    • Twisting
    • Shortening
    • PieceMark
    • DesignLocationNumber
  • Pset_RepairOccurrence
    • RepairContent
    • RepairDate
    • MeanTimeToRepair
  • Pset_Risk
    • RiskName
    • RiskType
    • NatureOfRisk
    • RiskAssessmentMethodology
    • UnmitigatedRiskLikelihood
    • UnmitigatedRiskConsequence
    • UnmitigatedRiskSignificance
    • MitigationPlanned
    • MitigatedRiskLikelihood
    • MitigatedRiskConsequence
    • MitigatedRiskSignificance
    • MitigationProposed
    • AssociatedProduct
    • AssociatedActivity
    • AssociatedLocation
  • Pset_ServiceLife
    • ServiceLifeDuration
    • MeanTimeBetweenFailure
  • Pset_Tolerance
    • ToleranceDescription
    • ToleranceBasis
    • OverallTolerance
    • HorizontalTolerance
    • OrthogonalTolerance
    • VerticalTolerance
    • PlanarFlatness
    • HorizontalFlatness
    • ElevationalFlatness
    • SideFlatness
    • OverallOrthogonality
    • HorizontalOrthogonality
    • OrthogonalOrthogonality
    • VerticalOrthogonality
    • OverallStraightness
    • HorizontalStraightness
    • OrthogonalStraightness
    • VerticalStraightness
  • Pset_Uncertainty
    • UncertaintyBasis
    • UncertaintyDescription
    • HorizontalUncertainty
    • LinearUncertainty
    • OrthogonalUncertainty
    • VerticalUncertainty
  • Pset_Warranty
    • WarrantyIdentifier
    • WarrantyStartDate
    • IsExtendedWarranty
    • WarrantyPeriod
    • WarrantyContent
    • PointOfContact
    • Exclusions
  • Pset_WindowLiningProperties
    • LiningDepth
    • LiningThickness
    • TransomThickness
    • MullionThickness
    • FirstTransomOffset
    • SecondTransomOffset
    • FirstMullionOffset
    • SecondMullionOffset
    • LiningOffset
    • LiningToPanelOffsetX
    • LiningToPanelOffsetY
  • Qto_BodyGeometryValidation
    • GrossSurfaceArea
    • NetSurfaceArea
    • GrossVolume
    • NetVolume
    • SurfaceGenusBeforeFeatures
    • SurfaceGenusAfterFeatures
  • Qto_MemberBaseQuantities
    • Length
    • CrossSectionArea
    • OuterSurfaceArea
    • GrossSurfaceArea
    • NetSurfaceArea
    • GrossVolume
    • NetVolume
    • GrossWeight
    • NetWeight

6.1.3.18.6 Concept usage

Concept Usage Description
IfcRoot (2)
IfcObjectDefinition (9)
IfcObject (5)
IfcProduct (18)
IfcElement (44)
IfcBuiltElement (3)
Click to show 81 hidden inherited concepts
IfcMember (11)
Axis 3D Geometry General

The axis representation can be used to represent the fundamental orientation and extents of a member's body.

If an IfcMaterialProfileSetUsage is used, the axis representation is used to locate the profile. In addition:

As shown in Figure 6.1.3.18.D, the axis representation can be used to represent the system length of a member that may extend past the body length of the member.

Axis
Figure 6.1.3.18.D — Member axis representation

As shown in Figure 6.1.3.18.H, the axis representation must be positioned at the IfcMaterialProfileSetUsage.CardinalPoint, and parallel to the IfcExtrudedAreaSolid.ExtrudedDirection. This offset between the axis line and the IfcExtrudedAreaSolid.Position must correlate with the chosen IfcMaterialProfileSetUsage.CardinalPoint.

Axis
Figure 6.1.3.18.H — Member axis cardinal point
Body AdvancedSweptSolid Geometry General
Body Clipping Geometry General

Figure 6.1.3.18.F illustrates a 'Clipping' geometric representation with use of IfcBooleanClippingResult between an IfcExtrudedAreaSolid and an IfcHalfSpaceSolid to create a clipped body.

clipped member
Figure 6.1.3.18.F — Member clipping

When an IfcMaterialProfileSetUsage is applied, Figure 6.1.3.18.G illustrates an advanced geometric representation with use of IfcBooleanClippingResult between an IfcExtrudedAreaSolid and an IfcHalfSpaceSolid to create a clipped body, with cardinal point applied as 4 (mid-depth left).

clipped beam
Figure 6.1.3.18.G — Member body clipping
Body SweptSolid Geometry General

When an IfcMaterialProfileSetUsage is assigned to the IfcMember:

  • For all single profiles, the IfcParameterizedProfileDef.Position shall be NIL, or having Location = 0.,0. and RefDirection = 1.,0.
  • The extrusion shall be perpendicular to the profile direction.
  • The y-axis of the profile, as determined by IfcSweptAreaSolid.Position.P[2] shall point to the Z-Axis. It indicates the "role" of the column, a role=0° means y-axis of profile = Z-axis of reference coordinate system. In the exception of a vertical member, the y-axis shall point to the Y-axis.

Figure 6.1.3.18.H illustrates a 'SweptSolid' geometric representation with cardinal point applied as 1 (bottom left).

If parametric profiles are used, the parameters may be interpreted to be the dimensions of the beam:

standard member
Figure 6.1.3.18.H — Member body extrusion
Material Profile Set Usage General

Figure 6.1.3.18.E illustrates assignment of IfcMaterialProfileSetUsage and IfcMaterialProfileSet to the IfcMemberType and the IfcMember occurrence. Both the IfcMaterialProfileSet and IfcProfileDef is shared between all occurrences.

Material profile set and usage
Figure 6.1.3.18.E — Member profile usage

Figure 6.1.3.18.I illustrates assignment of a composite profile by using IfcCompositeProfileDef for geometric representation and several IfcMaterialProfile entities within the IfcMaterialProfileSet.

Material profile set and usage
Figure 6.1.3.18.I — Member composite profiles
Object Typing General

This concept can be applied to the following resources:

Product Assignment General

This concept can be applied to the following resources:

Property Sets for Objects General

This concept can be applied to the following resources:

Quantity Sets General

This concept can be applied to the following resources:

Spatial Containment General

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

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

This concept can be applied to the following resources:

  • LoadBearing
Table 6.1.3.18.L

6.1.3.18.7 Formal representation

ENTITY IfcMember
SUBTYPE OF (IfcBuiltElement);
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
('IFC4X3_DEV_54a9de1b.IFCMEMBERTYPE' IN TYPEOF(SELF\IfcObject.IsTypedBy[1].RelatingType));
END_ENTITY;

6.1.3.18.8 References

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6.1.3.18.9 Changelog

6.1.3.18.9.1 IFC4

  • attribute, PredefinedType
  • where rule, CorrectPredefinedType
  • where rule, CorrectTypeAssigned

6.1.3.18.9.2 IFC4.3_DEV_54a9de1b