IFC 4.3.0.0 (IFC4X3) final

8.9.3.31 IfcDirectrixCurveSweptAreaSolid

ABSTRACT This definition may not be instantiated

8.9.3.31.1 Semantic definition

An abstract entity defining common information about a type of swept area solid which is the result of sweeping an area along a Directrix. The swept area is provided by a subtype of IfcProfileDef. The profile is placed by an implicit cartesian transformation operator at the start point of the sweep, where the profile normal agrees to the tangent of the directrix at this point. The direction of profile锟絪 x-axis is specialized by the subtypes of IfcDirextrixCurveSweptAreaSolid. The start of the sweeping operation is at the StartParam, the parameter value is provided based on the curve parameterization. If no StartParam is provided the start defaults to the begin of the directrix. The end of the sweeping operation is at the EndParam, the parameter value is provided based on the curve parameterization. If no EndParam is provided the end defaults to the end of the directrix.

8.9.3.31.2 Entity inheritance

8.9.3.31.3 Attributes

# Attribute Type Description
IfcRepresentationItem (2)
LayerAssignment SET [0:1] OF IfcPresentationLayerAssignment FOR AssignedItems

Assignment of the representation item to a single or multiple layer(s). The LayerAssignments can override a LayerAssignments of the IfcRepresentation it is used within the list of Items.
StyledByItem SET [0:1] OF IfcStyledItem FOR Item

Reference to the IfcStyledItem that provides presentation information to the representation, e.g. a curve style, including colour and thickness to a geometric curve.
IfcSolidModel (1)
* Dim IfcDimensionCount

This attribute is formally derived. 

3

The space dimensionality of this class, it is always 3.
IfcSweptAreaSolid (2)
1 SweptArea IfcProfileDef

The surface defining the area to be swept. It is given as a profile definition within the xy plane of the position coordinate system.
2 Position OPTIONAL IfcAxis2Placement3D

Position coordinate system for the resulting swept solid of the sweeping operation. The position coordinate system allows for re-positioning of the swept solid. If not provided, the swept solid remains within the position as determined by the cross section or by the directrix used for the sweeping operation.
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IfcDirectrixCurveSweptAreaSolid (3)
3 Directrix IfcCurve

The curve used to define the sweeping operation. The solid is generated by sweeping the SELF\IfcSweptAreaSolid.SweptArea along the Directrix.
4 StartParam OPTIONAL IfcCurveMeasureSelect

The parameter value on the Directrix at which the sweeping operation commences. If no value is provided the start of the sweeping operation is at the start of the Directrix.
5 EndParam OPTIONAL IfcCurveMeasureSelect

The parameter value on the Directrix at which the sweeping operation ends. If no value is provided the end of the sweeping operation is at the end of the Directrix.
Table 8.9.3.31.A

8.9.3.31.4 Formal propositions

Name Description
DirectrixBounded

If the values for StartParam or EndParam are omitted, then the Directrix has to be a bounded or closed curve.

 
(EXISTS(StartParam) AND EXISTS(EndParam)) OR 
(SIZEOF(['IFC4X3.IFCCONIC', 'IFC4X3.IFCBOUNDEDCURVE'] * TYPEOF(Directrix)) = 1)
Table 8.9.3.31.B

8.9.3.31.5 Formal representation 

ENTITY IfcDirectrixCurveSweptAreaSolid
 ABSTRACT SUPERTYPE OF (ONEOF
	(IfcFixedReferenceSweptAreaSolid
	,IfcSurfaceCurveSweptAreaSolid))
 SUBTYPE OF (IfcSweptAreaSolid);
	Directrix : IfcCurve;
	StartParam : OPTIONAL IfcCurveMeasureSelect;
	EndParam : OPTIONAL IfcCurveMeasureSelect;
 WHERE
	DirectrixBounded : (EXISTS(StartParam) AND EXISTS(EndParam)) OR 
(SIZEOF(['IFC4X3.IFCCONIC', 'IFC4X3.IFCBOUNDEDCURVE'] * TYPEOF(Directrix)) = 1);
END_ENTITY;

8.9.3.31.6 References

8.9.3.31.7 Changelog

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