Defined in File Ifc4x1.h
IfcProjectionElement: public Ifc4x1::IfcFeatureElementAddition¶
The projection element is a specialization of the general feature element to represent projections applied to building elements. It represents a solid attached to any element that has physical manifestation. EXAMPLE A wall projection such as a pilaster strip is handled by IfcProjectionElement NOTE View definitions or implementer agreements may restrict the types of elements to which IfcProjectionElement can be applied. An IfcProjectionElement has to be linked to a element (all subtypes of IfcElement) by using the IfcRelProjectsElement relationship. Its existence depends on the existence of the master element. The relationship implies a Boolean union operation between the volume of the projection element and the volume of the element. HISTORY New entity in IFC2x2. IFC2x4 CHANGE The attribute PredefinedType has been added at the end of attribute list. The quantities relating to the IfcProjectionElement 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, being subjected to local standard of measurement, can be defined with another string value assigned to Name. In this case a valid value for MethodOfMeasurement has to be provided.
Qto_ProjectionElementBaseQuantities: base quantities for all opening occurrences.
Containment Use Definition The IfcProjectionElement shall not participate in the containment relationship, i.e. it is not linked directly to the spatial structure of the project. It has a mandatory ProjectsElements inverse relationship pointing to the IfcElement that is contained in the spatial structure.
The inverse relationship ContainedInStructure shall be NIL.
Geometry Use Definition The geometric representation of IfcProjectionElement is given by the IfcProductDefinitionShape and IfcLocalPlacement allowing multiple geometric representations. Local Placement The local placement for IfcOpeningRecess 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 should point to the local placement of the same element, to which the projection adds, i.e. referred to by ProjectsElement.RelatingBuildingElement.
Swept Solid Representation The geometric representation of IfcProjectionElement is defined using the swept area solid geometry. 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 swept solid representation:
Solid: IfcExtrudedAreaSolid is required. Profile: IfcRectangleProfileDef, IfcCircleProfileDef and IfcArbitraryClosedProfileDef shall be supported. Extrusion: The profile shall be extruded horizontally (that is, perpendicular to the extrusion direction of the modified element), such as for wall projections, or vertically (that is, in the extrusion direction of the projected element), such as for floor projections.
As shown in Figure 38, the following interpretation of dimension parameter applies for rectangular projection:
NOTE Rectangles are now defined centric, the placement location has to be set: IfcCartesianPoint(XDim/2,YDim/2) NOTE The local placement directions for the IfcProjectionElement are only given as an example, other directions are valid as well.
Figure 38 — Projection representation
Brep Representation The general b-rep geometric representation of IfcProjectionElement is defined using the Brep geometry. The Brep representation allows for the representation of complex element shape. The following attribute values for the IfcShapeRepresentation holding this geometric representation shall be used:
RepresentationIdentifier : ‘Body’ RepresentationType : ‘Brep’
Whether the optional attribute PredefinedType is defined for this IfcProjectionElement.
Predefined generic type for a projection element that is specified in an enumeration. There may be a property set given specificly for the predefined types.
IFC2x4 CHANGE The attribute has been added at the end of the entity definition.
IfcProjectionElement(std::string v1_GlobalId, ::Ifc4x1::IfcOwnerHistory *v2_OwnerHistory, boost::optional<std::string> v3_Name, boost::optional<std::string> v4_Description, boost::optional<std::string> v5_ObjectType, ::Ifc4x1::IfcObjectPlacement *v6_ObjectPlacement, ::Ifc4x1::IfcProductRepresentation *v7_Representation, boost::optional<std::string> v8_Tag, boost::optional<::Ifc4x1::IfcProjectionElementTypeEnum::Value> v9_PredefinedType)¶