# 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�s 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.

## 8.9.3.31.5 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_DEV_9f90c1f0.IFCCONIC', 'IFC4X3_DEV_9f90c1f0.IFCBOUNDEDCURVE'] * TYPEOF(Directrix)) = 1);
END_ENTITY;