Defined in File Ifc4.h
IfcWall: public Ifc4::IfcBuildingElement¶
Definition from ISO 6707-1:1989: Vertical construction usually in masonry or in concrete which bounds or subdivides a construction works and fulfils a load bearing or retaining function. Definition from IAI: The wall represents a vertical construction that bounds or subdivides spaces. Wall are usually vertical, or nearly vertical, planar elements, often designed to bear structural loads. A wall is howevernot required to be load bearing. NOTE NOTE There is a representation of walls for structural analysis provided by a proper subtype of IfcStructuralMember being part of the IfcStructuralAnalysisModel.
NOTE An arbitrary planar element to which this semantic information is not applicable, e.g. is not predominantly vertical, shall be modeled as IfcPlate A wall may have openings, such as wall openings, openings used for windows or doors, or niches and recesses. They are defined by an IfcOpeningElement attached to the wall using the inverse relationship HasOpenings pointing to IfcRelVoidsElement. The IFC specification provides two entities for wall occurrences:
IfcWallStandardCase used for all occurrences of walls, that have a non-changing thickness along the wall path and where the thickness parameter can be fully described by a material layer set. These walls are always represented geometrically by an ‘Axis’ and a ‘SweptSolid’ shape representation (or by a ‘Clipping’ geometry based on ‘SweptSolid’), if a 3D geometric representation is assigned. In addition they have to have a corresponding IfcMaterialProfileSetUsage assigned. IfcWallElementedCase used for occurrences of walls which are aggregated from subordinate elements, following specific decomposition rules expressed by the mandatory use of IfcRelAggregates relationship. IfcWall used for all other occurrences of wall, particularly for walls with changing thickness along the wall path (e.g. polygonal walls), or walls with a non-rectangular cross sections (e.g. L-shaped retaining walls), and walls having an extrusion axis that is unequal to the global Z axis of the project (i.e. non-vertical walls), or walls having only ‘Brep’, or ‘SurfaceModel’ geometry.
HISTORY New entity in IFC Release 1.0 Type Use Definition IfcWall defines the occurrence of any wall, common information aboutwall types (or styles) is handled by IfcWallType. The IfcWallType (if present) may establish the commontype name, usage (or predefined) type, common material layer set, common set of properties and common shape representations (using IfcRepresentationMap). The IfcWallType is attached using the IfcRelDefinedByType.RelatingType objectified relationship and is accessible by the inverse IsTypedBy attribute. If no IfcWallType is attached(i.e. if only occurrence information is given) the PredefinedType should be provided. If set to .USERDEFINED. a user defined value can be provided by the ObjectType attribute. Material Use Definition The material of the IfcWall is defined by IfcMaterialLayerSet and attached by the IfcRelAssociatesMaterial.RelatingMaterial. It is accessible by the inverse HasAssociations relationship. Multi-layer walls can be represented by referring to several IfcMaterialLayer’s within the IfcMaterialLayerSet. Note: It is illegal to assign an IfcMaterialLayerSetUsage to an IfcWall. Only the subtype IfcWallStandardCase supports this concept. Material information can also be given at the IfcWallType, defining the common attribute data for all occurrences of the same type.It is then in addition accessible by the inverse IsTypedBy relationship pointing to IfcWallType.HasAssociations and via IfcRelAssociatesMaterial.RelatingMaterial. Property Set Use Definition The property sets relating to the IfcWall are defined by the IfcPropertySet and attached by the IfcRelDefinesByProperties relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to the IfcWall are part of this IFC release:
Pset_WallCommon: common property set for all wall occurrences
Property sets can also be given at the IfcWallType, defining the common property data for all occurrences of the same type.It is then accessible by the inverse IsTypedBy relationship pointing to IfcWallType.HasPropertySets. If both are given, then the properties directly assigned to IfcWall overrides the properties assigned to IfcWallType. Quantity Use Definition The quantities relating to the IfcWall and IfcWallStandardCase are defined by the IfcElementQuantity and attached by the IfcRelDefinesByProperties relationship. It is accessible by the inverse IsDefinedBy relationship. The following base quantities are defined and should be exchanged with the IfcElementQuantity.Name = ‘BaseQuantities’. Other quantities can be defined being subjected to local standard of measurement with another string value assigned to Name and a value provided for MethodOfMeasurement. Quantities shall never be assigned to the IfcWallType.
Qto_WallBaseQuantities: base quantities for all wall occurrences.
Containment Use Definition The IfcWall (and the subtype IfcWallStandardCase) as any subtype of IfcBuildingElement, may participate in two different containment relationships. The first (and in most implementation scenarios mandatory) relationship is the hierarchical spatial containment, the second (optional) relationship is the aggregation within anelement assembly.
The IfcWall is places within the project spatial hierarchy using the objectified relationship IfcRelContainedInSpatialStructure, referring to it by its inverse attribute SELF\IfcElement.ContainedInStructure. Subtypes ofIfcSpatialStructureElement are valid spatial containers, with IfcBuildingStorey being the default container. TheIfcWall may be aggregated into an element assembly using the objectified relationship IfcRelAggregates, referring to it by its inverse attribute SELF\IfcObjectDefinition.Decomposes. Any subtype of IfcElement can be an element assembly, with IfcElementAssembly as a special focus subtype. In this case the wall should not be additionally contained in the project spatial hierarchy, i.e.SELF\IfcElement.ContainedInStructure should be NIL.
TheIfcWallmay also be an aggregate i.e. being composed by other elements and acting as an assembly using the objectified relationship IfcRelAggregates, referring to it by its inverse attribute SELF\IfcObjectDefinition.IsDecomposedBy. Components of a wall are described by instances of IfcBuildingElementPart that are aggregated to form a complex wall. In this case, the containedIfcBuildingElementPart’s should not be additionally contained in the project spatial hierarchy, i.e. the inverse attribute SELF\IfcElement.ContainedInStructure of IfcBuildingElementPart should be NIL. Geometry Use Definition The geometric representation of IfcWall is given by the IfcProductDefinitionShape, allowing multiple geometric representation. Included are: Local Placement The local placement for IfcWall 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.
The PlacementRelTo relationship of IfcLocalPlacement shall point (if given) to the local placement of the same IfcSpatialStructureElement that is used in the ContainedInStructure inverse attribute or to a referenced spatial structure element at a higher level. If the relative placement is not used, the absolute placement is defined within the world coordinate system.
Geometric Representation Currently, the ‘Axis’, ‘Surface’, ‘FootPrint’, ‘Body’, and ‘Box’ representations are supported. The ‘Box’ representation includes the representation type ‘BoundingBox’ and is explained at IfcBuildingElement. Axis Representation The axis geometric representation of IfcWall is defined using the ‘Axis’ representation.
RepresentationIdentifier : ‘Axis’ RepresentationType : ‘Curve2D’
NOTE The ‘Axis’ is not used to locate the material layer set, only the subtype IfcWallStandardCase provides this capability. Surface Representation The surfacic geometric representation of IfcWall is defined using the ‘Surface’ representation.
RepresentationIdentifier : ‘Surface’ RepresentationType : ‘Surface3D’
NOTE The ‘Surface’ can be used to define a surfacic model of the building (e.g. for analytical purposes, or for reduced Level of Detail representation). Body Representation The body representation of IfcWall can be represented using the representation types ‘SweptSolid’, ‘Clipping’, ‘SurfaceModel’, and ‘Brep’. The representation types ‘SurfaceModel’ and ‘Brep’ are explained at IfcBuildingElement. SweptSolid Representation Type The following attribute values for the IfcShapeRepresentation holding this geometric representation shall be used: If the wall body can be described by a vertical extrusion of a polygonal footprint with constant thickness along the axis (where vertical = into the direction of the global Z axis), the subtype IfcWallStandardCase should be used. If the extrusion is not equal to global Z, then the IfcWall should be used.
RepresentationIdentifier : ‘Body’ RepresentationType : ‘SweptSolid’
The following additional constraints apply to the ‘SweptSolid’ representation:
Clipping Representation Type The following attribute values for the IfcShapeRepresentation holding this geometric representation shall be used:
RepresentationIdentifier : ‘Body’ RepresentationType : ‘Clipping’
The same additional constraints apply as defined for the ‘SweptSolid’ representation. Connection Geometry The connection between two walls is represented by the IfcRelConnectsPathElements. The use of the parameter of that relationship object is defined at the level of the subtypes of IfcWall and at the IfcRelConnectsPathElements.
Whether the optional attribute PredefinedType is defined for this IfcWall.
Predefined generic type for a wall that is specified in an enumeration. There may be a property set given specifically for the predefined types. NOTE The PredefinedType shall only be used, if no type object IfcWallType is assigned, providing its own IfcWallType.PredefinedType.
IFC2x4 CHANGE The attribute has been added at the end of the entity definition.
IfcWall(std::string v1_GlobalId, ::Ifc4::IfcOwnerHistory *v2_OwnerHistory, boost::optional<std::string> v3_Name, boost::optional<std::string> v4_Description, boost::optional<std::string> v5_ObjectType, ::Ifc4::IfcObjectPlacement *v6_ObjectPlacement, ::Ifc4::IfcProductRepresentation *v7_Representation, boost::optional<std::string> v8_Tag, boost::optional<::Ifc4::IfcWallTypeEnum::Value> v9_PredefinedType)¶