Defined in File Ifc4.h
IfcWallStandardCase: public Ifc4::IfcWall¶
The IfcWallStandardCase defines a wall with certain constraints for the provision of parameters and with certain constraints for the geometric representation. The IfcWallStandardCase handles all cases of walls, that are extruded vertically:
along the positive z axis of the wall object coordinate system, and along the positve z axis of the global (world) coordinate system
and have a single thickness along the path for each wall layer, i.e.:
parallel sides for straight walls co-centric sides for curved walls.
and have either:
a straight line axis (straight wall), or a circular arc axis (round wall).
and shall not have
aggregated components, that is, parts aggregated to a wall by IfcRelAggregates shape representation for ‘Body’ not being an extrusion, or clipped extrusion
The following parameter have to be provided:
Wall height, taken from the depth of extrusion, provided by the geometric representation. Wall thickness, taken from the material layer set usage, attached to the wall Wall offset from axis, taken from the material layer set usage, attached to the wall
The IfcWallStandardCase requires the provision of the wall axis either a straight line that is parallel to the x-axis of the object coordinate system, or a circular arc where the tangent at start is parallel to the x-axis of the object coordinate system. The direction of the wall axis shall be the positive direction of that x-axis. The material of the wall is defined by the IfcMaterialLayerSetUsage and is attached by the IfcRelAssociatesMaterial objectified relationship. It is accessible by the inverse HasAssociations relationship. The material layer set usage has to be given (enforced by where rule). HISTORY New entity in IFC Release 2x.
Type Use Definition The type information relating to the IfcWallStandardCase is defined at the supertype IfcWall. As an additional use agreement for standard walls, the IfcWallType should have a unique IfcMaterialLayerSet, that is referenced by theIfcMaterialLayerSetUsage assigned to all occurrences of this IfcWallType.
Material Use Definition The material of the IfcWallStandardCase is defined by IfcMaterialLayerSetUsage and attached by the IfcRelAssociatesMaterial.RelatingMaterial. It is accessible by the inverse HasAssociations relationship. Multi-layer walls can be represented by refering to several IfcMaterialLayer’s within the IfcMaterialLayerSet that is referenced from the IfcMaterialLayerSetUsage. Material information can also be given at the IfcWallType, defining the common attribute data for all occurrences of the same type.It is then accessible by the inverse IsDefinedBy relationship pointing to IfcSlabType.HasAssociations and via IfcRelAssociatesMaterial.RelatingMaterial. See Type Use Definition for additional agreements for standard slabs.
Figure 134 illustrates material layer usage, where the following conventions shall be met:
The reference coordinate system is the local coordinate system established by the ObjectPlacement of the IfcWallStandardCase. The reference axis is the axis defined by the IfcShapeRepresentation with RepresentationType=’Axis’ as one of the Representation.Representations of the IfcWallStandardCase. The IfcMaterialLayerSetUsage.OffsetFromReferenceLine is given as a distance from this axis. The IfcMaterialLayerSetUsage.OffsetFromReferenceLine is the distance parallel to the reference axis and always within the base (XY) plane of the reference coordinate system. A positve value of IfcMaterialLayerSetUsage.OffsetFromReferenceLine would then point into the positive y-axis of the reference coordinate system. The IfcMaterialLayerSetUsage.DirectionSense defines how the IfcMaterialLayer’s are assigned to the reference axis. POSITIVE means in direction to the positive y-axis of the reference coordinate system. The Thickness of each IfcMaterialLayer is provided starting from the OffsetFromReferenceLine and in the direction given by DirectionSense. It is applied without any gap or overlap between two consecutive layers. The TotalThickness of the IfcMaterialLayerSet is the sum of all layer thicknesses. The IfcMaterialLayerSetUsage.LayerSetDirection is always AXIS2.
Figure 134 — Wall material layers
Property Set Use Definition: The property sets relating to the IfcWallStandardCase are defined at the supertype IfcWall. Quantity Use Definition: The quantities relating to the IfcWallStandardCase are defined at the supertype IfcWall. Geometry Use Definitions: The geometric representation of IfcWallStandardCase is given by the IfcProductDefinitionShape, allowing multiple geometric representation. Included are: Local Placement The use of local placement defining the wall object coordinate system is defined at the supertype IfcWall. Geometric Representation The standard geometric representation of IfcWallStandardCase is defined using the following multiple shape representations for its definition:
Axis: A two-dimensional open curve (IfcBoundedCurve) defining the axis for the standard wall. The material layer offset is measured from the wall axis. Body: A Swept Solid Representation or a CSG representation defining the 3D shape of the standard wall
NOTE It is invalid to exhange a ‘SurfaceModel’, or ‘Brep’ or ‘MappedRepresentation’ representation for the ‘Body’ shape representation of an IfcWallStandardCase. Axis Representation The wall axis is represented by a two-dimensional open curve within a particular shape representation. The wall axis is used to apply the material layer set usage parameter to the wall geometry. The following attribute values shall be used
RepresentationIdentifier : ‘Axis’ RepresentationType : ‘Curve2D’
Figure 135 illustrates an axis representation for a straight wall. In case of a straight wall, the set of items shall include a single geometric representation item of type IfcPolyline or IfcTrimmedCurve with the BasisCurve being an IfcLine. The IfcPolyline or IfcTrimmedCurve shall be parallel (here in a special case co-linear) to the x-axis of the object coordinate system. The direction shall be identical to the direction of the x-axis.
Figure 136 illustrates an axis representation for a curved wall. In case of a curved wall, the set of items shall include a single geometric representation item of type IfcTrimmedCurve. The curve shall have a BasisCurve of type IfcCircle. The tangent of the IfcTrimmedCurve shall be parallel at start to the x-axis of the object coordinate system. The direction shall be identical to the direction of the x-axis.
Figure 135 — Wall axis straight Figure 136 — Wall axis curved
Body Representation The body representation of IfcWallStandardCase is defined by using ‘SweptSolid’ representation for walls without clippings or ‘Clipping’ representation for walls with clippings (e.g. under sloped roof slabs). SweptSolid Representation Type The following attribute values for the IfcShapeRepresentation holding this geometric representation shall be used:
RepresentationIdentifier : ‘Body’ RepresentationType : ‘SweptSolid’
The following additional constraints apply to the ‘SweptSolid’ representation:
Solid: IfcExtrudedAreaSolid is required, Profile: IfcArbitraryClosedProfileDef and IfcRectangleProfileDef shall be supported. Extrusion: The profile shall be extruded vertically, i.e., in the direction of the z-axis of the co-ordinate system of the referred spatial structure element. It might be further constraint to be in the direction of the global z-axis in implementers agreements. The extrusion axis shall be perpendicular to the swept profile, i.e. pointing into the direction of the z-axis of the Position of the IfcExtrudedAreaSolid.
The profile of a wall is described in the ground view and extruded vertically. The profile (also identical with the foot print of the wall) is defined by the IfcArbitraryClosedProfileDef (excluding its subtypes). The profile is given with all wall connections already resolved.
Figure 137 illustrates a body representation for a straight wall. In case of a straight wall, the two sides of the profile shall be parallel to the wall axis, that is, the wall has a single unchanged thickness.
Figure 138 illustrates a body representation for a curved wall. In case of a curved wall, the two sides of the profile shall be parallel (with defined offset) to the wall axis, that is, the wall has a single unchanged thickness.
Figure 137 — Wall body extrusion straight Figure 138 — Wall body extrusion curved
Clipping Representation Type The following attribute values for the IfcShapeRepresentation holding this geometric representation shall be used:
RepresentationIdentifier : ‘Body’ RepresentationType : ‘Clipping’
The following constraints apply to the ‘Clipping’ representation:
Solid: see standard geometric representation Profile: see standard geometric representation Extrusion: see standard 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 subtypes).
Figure 139 — Wall body clipping straight Figure 140 — Wall body clipping curved
IfcWallStandardCase(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)¶