Defined in File Ifc4x3_rc1.h
IfcFixedReferenceSweptAreaSolid: public Ifc4x3_rc1::IfcDirectrixCurveSweptAreaSolid¶
A fixed reference swept area solid is a type of swept area solid which is the result of sweeping a surface along a Directrix. The orientation of the curve during the sweeping operation is controlled by the FixedReference direction. The SweptArea is required to be a curve bounded surface lying in the plane z = 0 and this is swept along the Directrix in such a way that the origin of the local coordinate system used to define the SweptArea is on the Directrix and the local X axis is in the direction of the projection of FixedReference onto the normal plane to the directrix at this point. The resulting solid has the property that the cross section of the surface by the normal plane to the Directrix at any point is a copy of the SweptArea.
NOTE The swept face is given by IfcProfileDef (or subtypes), the profile definition is given within a 2D coordinate system, which is inserted into the XY plane of the Position coordinate system inherited from the supertype IfcSweptAreaSolid.
The orientation of the SweptArea as it sweeps along the Directrix is precisely defined by a CartesianTransformationOperator3d with attributes:
LocalOrigin as point (0; 0; 0), Axis1 as the FixedReference. Axis3 as the direction of the tangent vector t at the point of the Directrix with parameter u.
The remaining attributes are defaulted to define a corresponding transformation matrix T(u), which varies with the Directrix parameter u.
NOTE The geometric shape of the solid is not dependent upon the curve parameterization; the volume depends upon the area swept and the length of the Directrix.
The attributes of the Cartesian Transformation Operator (as shown above) should apply to the Position coordinate system, in which the profile is inserted. The Directrix and the FixedReference are positioned within the 3D Position coordinate system.
NOTE The entity is defined in analogy to the ISO 10303-42 entity: fixed_reference_swept_surface. Please refer to ISO/DIS 10303-42:2003(E) p. 103.
HISTORY New entity in IFC2x4.
The SweptArea shall lie in the plane z = 0. The FixedReference shall not be parallel to a tangent vector to the directrix at any point along this curve. The Directrix curve shall be tangent continuous.
The direction providing the fixed axis1 (x-axis) direction for orienting the swept area during the sweeping operation along the Directrix.
- ::Ifc4x3_rc1::IfcDirection *