IfcStructuralCurveMember

Definition from IAI: Instances of the entity IfcStructuralCurveMember shall be used to describe linear structural elements. Profile and material properties are defined by using objectified relationships:

• The material properties are defined by IfcMechanicalMaterialProperties (and subtypes), they are connected through IfcMaterial and IfcRelAssociatesMaterial and are accessible via the inherited inverse relationship HasAssociations.
• The profile properties are defined by IfcMechanicalProfileProperties (and subtypes), they are connected through IfcRelAssociatesProfileProperties and are accessible via the inherited inverse relationship HasAssociations.

HISTORY: New entity in Release IFC2x Edition 2.

Use Definition

The topological (or axis) representation of the structural curve member is given by assigning an edge through the general Representation capability inherited by IfcProduct. For linear structural curve members the use of IfcEdge is sufficient, since a linear interpolation between the two vertices is assumed, if the structural curve member is an arc, or other non-linear form, the IfcEdgeCurve needs to be used instead, having the geometric form of the curve between the two vertices fully defined. A single, constant, profile definition is assigned to the structural curve member through the IfcRelAssociatedProfileProperties.

Topology Use Definition

Instances of IfcStructuralCurveMember shall have a topology representation. It includes a placement and a product representation. The IfcProductRepresentation shall be given by an item of Representations being of type "IfcTopologyRepresentation".

Placement

The placement for IfcStructuralCurveMember is determined at its supertype IfcProduct. It is defined by the optional IfcObjectPlacement, referenced by ObjectPlacement at IfcProduct, which establishes, if given, the object coordinate system that is referenced by all topological representations of that product.

• If the ObjectPlacement attribute is omitted, then all topological representations are given directly in world coordinates. This is the preferred representation.
• If the ObjectPlacement attribute is provided, then it establishes an object coordinate system for all topological representations which are given object coordinates.
  • If the PlacementRelTo relationship of IfcLocalPlacement is omitted, the object coordinate system is established within the world coordinate system.
  • If the PlacementRelTo relationship of IfcLocalPlacement is given, it shall point to the local placement of the same IfcSpatialStructureElement, which is used in the ContainedInStructure inverse attribute, or to a spatial structure element at a higher level, referenced by that.

Topology Representation

Instances of IfcStructuralCurveMember shall have a topology representation given by an edge with an optional additional geometric representation of the included curve. It can be provided by either

• IfcEdge
• IfcOrientedEdge
• IfcEdgeCurve

which should be the single item of IfcTopologyRepresentation.Items. The IfcEdge might be referenced by two or many IfcSubedge, representing sections of the IfcStructuralCurveMember with changing properties. See subtype IfcStructuralCurveMemberVarying for the use definition.

EXPRESS specification:

Attribute definitions:

Inheritance graph