IfcStructuralCurveMember

#	Attribute	Type	Cardinality	Description	B
8	PredefinedType	IfcStructuralCurveMemberTypeEnum	[1:1]	Type of member with respect to its load carrying behavior in this analysis idealization.	X
9	Axis	IfcDirection	[1:1]	Direction which is used in the definition of the local z axis. Axis is specified relative to the so-called global coordinate system, i.e. the SELF\IfcProduct.ObjectPlacement. NOTE It is desirable and usually possible that many instances of IfcStructuralCurveConnection and IfcStructuralCurveMember share a common instance of IfcDirection as their Axis attribute.	X

Rule	Description
HasObjectType	The attribute ObjectType shall be given if the predefined type is set to USERDEFINED.

Inherited definitions from supertypes

Entity inheritance

Attribute inheritance

#	Attribute	Type	Cardinality	Description	B
IfcRoot
1	GlobalId	IfcGloballyUniqueId	[1:1]	Assignment of a globally unique identifier within the entire software world.	X
2	OwnerHistory	IfcOwnerHistory	[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
3	Name	IfcLabel	[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
4	Description	IfcText	[0:1]	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).
	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).	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.
	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).	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).	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	-		This attribute is out of scope for this model view definition and shall not be set.
	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.	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.	X
IfcProduct
6	ObjectPlacement	IfcObjectPlacement	[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
7	Representation	IfcProductRepresentation	[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
	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
IfcStructuralItem
	AssignedStructuralActivity	IfcRelConnectsStructuralActivity @RelatingElement	S[0:?]	Inverse relationship to all structural activities (i.e. to actions or reactions) which are assigned to this structural member.	X
IfcStructuralMember
	ConnectedBy	IfcRelConnectsStructuralMember @RelatingStructuralMember	S[0:?]	Inverse relationship to all structural connections (i.e. to supports or connecting elements) which are defined for this structural member.	X
IfcStructuralCurveMember
8	PredefinedType	IfcStructuralCurveMemberTypeEnum	[1:1]	Type of member with respect to its load carrying behavior in this analysis idealization.	X
9	Axis	IfcDirection	[1:1]	Direction which is used in the definition of the local z axis. Axis is specified relative to the so-called global coordinate system, i.e. the SELF\IfcProduct.ObjectPlacement. NOTE It is desirable and usually possible that many instances of IfcStructuralCurveConnection and IfcStructuralCurveMember share a common instance of IfcDirection as their Axis attribute.	X

Definitions applying to Bridge View

Instance diagram

This entity captures the idealized structural model of a linear member such as a girder (IfcBeam) or cross-frame member (IfcMember). Camber ordinates may be obtained by traversing the structural results for total dead load.

Concept usage

Structural Connectivity

The Structural Connectivity concept applies to this entity as shown in Table 81.

StructuralConnection	Description
IfcStructuralPointConnection	Point connections at each end of the member.

Table 81 — IfcStructuralCurveMember Structural Connectivity

Exchange
Import
Export

Material Profile Set Usage

The Material Profile Set Usage concept applies to this entity.

The material of direct instances IfcStructuralCurveMember (in contrast to instances of the subtype IfcStructuralCurveMemberVarying) is defined by IfcMaterialProfileSetUsage and attached by the IfcRelAssociatesMaterial.RelatingMaterial. It is accessible by the inverse HasAssociations relationship. Composite profile beams can be represented by refering to several IfcMaterialProfiles within the IfcMaterialProfileSet that is referenced from the IfcMaterialProfileSetUsage. In case of tapered members, the material profile usage subtype IfcMaterialProfileSetUsageDual is used which specifies IfcMaterialProfileSets separately at the start and the end of the tapered member.

The material (IfcMaterial) in each IfcMaterialProfile(Set) is specified minimally by a name which corresponds with an agreed upon standardized structural material designation. An external reference to the source which specifies the material designation should be provided. Alternatively, structural material properties may be provided by means of IfcMechanicalMaterialProperties and IfcExtendedMaterialProperties.

The profile (IfcProfileDef) in each IfcMaterialProfile(Set) is specified minimally by a name which corresponds with an agreed upon standardized structural profile designation. An external reference to the source which specifies the profile designation should be provided. Alternatively or additionally, explicit profile geometry should be provided by using respective subtypes of IfcProfileDef. Alternatively or additionally, structural profile properties may be provided by means of subtypes of IfcProfileProperties.

An IfcProfileDef is a two-dimensional geometric object with a x_p,y_p coordinate system. The profile is inserted into the curve member model thus that the origin of x_p,y_p is located at the member's reference curve and that x_p,y_p are parallel with and directed like the local y,z.

NOTE Due to convention in structural mechanics, axis names of IfcStructuralCurveMember differ from axis names of building elements like IfcBeamStandardCase: The extrusion axis of IfcStructuralCurveMember is called x while the extrusion axis of IfcBeamStandardCase is called z. Hence x,y,z of IfcStructuralCurveMember correspond with z,x,y of IfcBeamStandardCase.

If the profile is meant to be inserted centrically in terms of structural section properties, it is necessary that the origin of x_p,y_p is identical with the geometric centroid of the profile (commonly also called centre of gravity). If subtypes of IfcParameterizedProfileDef are used which are only singly symmetric or are asymmetric, an explicit translation by IfcParameterizedProfileDef.Position.Location is required then.

If the profile is inserted at its geometric centroid, IfcMaterialProfileSetUsage.CardinalPoint shall be set to 10.

Otherwise, the profile is inserted eccentrically and a different cardinal point should be set accordingly.

NOTE Another eccentricity model is available independently of eccentric profile specification: The reference curve of the member may be located eccentrically relative to the reference points of the connected IfcStructuralPointConnections. The connection relationship is then established by IfcRelConnectsWithEccentricity. Whether one or the other or both eccentricity models may be used is subject to information requirements and local agreements.

Exchange
Import		R
Export		R

Reference Topology

The Reference Topology concept applies to this entity as shown in Table 82.

Topology
IfcEdge

Table 82 — IfcStructuralCurveMember Reference Topology

Direct instances of IfcStructuralCurveMember shall have a topology representation which consists of one instance of IfcEdge or a subtype, representing the reference curve of the curve member. See definitions at IfcStructuralItem for further specifications.

Informal Propositions:

The reference curve must not be parallel with Axis at any point within the curve member's domain.

The local coordinate system is established by the reference curve given by topology representation and by the attribute Axis. The local x axis is parallel with the tangent on the reference curve. The local z axis is located in the surface which is created by sweeping Axis along the reference curve and is directed according to Axis. The local y axis is directed such that x,y,z form a right-handed Cartesian coordinate system.

Exchange
Import
Export

Concept inheritance

#	Concept	Model View
IfcRoot
	Software Identity	Bridge View
	User Identity	Bridge View
	Object Ownership	Bridge View
IfcObject
	Property Sets for Objects	Bridge View
IfcStructuralCurveMember
	Structural Connectivity	Bridge View
	Material Profile Set Usage	Bridge View
	Reference Topology	Bridge View

Formal representations

XSD Specification

 <xs:element name="IfcStructuralCurveMember" type="ifc:IfcStructuralCurveMember" substitutionGroup="ifc:IfcStructuralMember" nillable="true"/>

 <xs:complexType name="IfcStructuralCurveMember">

  <xs:complexContent>

   <xs:extension base="ifc:IfcStructuralMember">

    <xs:sequence>

     <xs:element name="Axis" type="ifc:IfcDirection" nillable="true"/>

    </xs:sequence>

    <xs:attribute name="PredefinedType" type="ifc:IfcStructuralCurveMemberTypeEnum" use="optional"/>

   </xs:extension>

  </xs:complexContent>

 </xs:complexType>

EXPRESS Specification


ENTITY IfcStructuralCurveMember

 SUPERTYPE OF(IfcStructuralCurveMemberVarying)

 SUBTYPE OF (IfcStructuralMember);

  PredefinedType : IfcStructuralCurveMemberTypeEnum;

  Axis : IfcDirection;

 WHERE

  HasObjectType : (PredefinedType <> IfcStructuralCurveMemberTypeEnum.USERDEFINED) OR EXISTS(SELF\IfcObject.ObjectType);
END_ENTITY;

 EXPRESS-G diagram

Link to this page

Item	Change	Description
IFC2x3 to IFC4
IfcStructuralCurveMember
OwnerHistory	MODIFIED	Instantiation changed to OPTIONAL.
PredefinedType	MODIFIED	Type changed from IfcStructuralCurveTypeEnum to IfcStructuralCurveMemberTypeEnum.
Axis	ADDED

	Stab / Seil / Balken mit konstantem Profil / Querschnitt: lineares statisches Bauteil mit Beanspruchung auf Zug, Druck, Biegung oder Torsion
	Structural Curve Member

IfcStructuralCurveMember

Semantic definitions at the entity

Inherited definitions from supertypes

Definitions applying to Bridge View

Formal representations