IfcCartesianTransformationOperator2DnonUniform

笛卡尔变换算子2d非均匀定义了二维空间中由平移、旋转、镜像和非均匀缩放组成的几何变换。非均匀缩放由两个不同的缩放因子给出：

①IfcCartesianTransformationOperator.Scale：x轴比例因子

②Scale2:y轴比例因子

如果忽略比例因子（在超级类型IfcCartesianTransformationOperator处），则默认为1.0。如果省略Scale2因子，则默认为Scale的值（x轴比例因子）。

注意，在超级类型IfcCartesianTransformationOperator中定义的比例因子（Scl）用于表示计算的比例因子（通常为x轴比例因子）。

在IFC2x中增加的新实体。

#	Attribute	Type	Cardinality	Description	C
IfcRepresentationItem
	LayerAssignment	IfcPresentationLayerAssignment @AssignedItems	S[0:1]	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.	X
	StyledByItem	IfcStyledItem @Item	S[0:1]	Reference to the IfcStyledItem that provides presentation information to the representation, e.g. a curve style, including colour and thickness to a geometric curve.	X
IfcGeometricRepresentationItem
IfcCartesianTransformationOperator
1	Axis1	IfcDirection	[0:1]	The direction used to determine U[1], the derived X axis direction.	X
2	Axis2	IfcDirection	[0:1]	The direction used to determine U[2], the derived Y axis direction.	X
3	LocalOrigin	IfcCartesianPoint	[1:1]	The required translation, specified as a cartesian point. The actual translation included in the transformation is from the geometric origin to the local origin.	X
4	Scale	IfcReal	[0:1]	The scaling value specified for the transformation.	X
	Scl :=NVL(Scale, 1.0)	IfcReal	[1:1]	The derived scale S of the transformation, equal to scale if that exists, or 1.0 otherwise.	X
	Dim :=LocalOrigin.Dim	IfcDimensionCount	[1:1]	The space dimensionality of this class, determined by the space dimensionality of the local origin.	X
IfcCartesianTransformationOperator2D
	U :=IfcBaseAxis(2,SELFIfcCartesianTransformationOperator.Axis1, SELFIfcCartesianTransformationOperator.Axis2,?)	IfcDirection	L[2:2]	The list of mutually orthogonal, normalized vectors defining the transformation matrix T. They are derived from the explicit attributes Axis1 and Axis2 in that order.	X
IfcCartesianTransformationOperator2DnonUniform
5	Scale2	IfcReal	[0:1]	The scaling value specified for the transformation along the axis 2. This is normally the y scale factor.	X
	Scl2 :=NVL(Scale2, SELFIfcCartesianTransformationOperator.Scl)	IfcReal	[1:1]	The derived scale S(2) of the transformation along the axis 2 (normally the y axis), equal to Scale2 if that exists, or equal to the derived Scl1 (normally the x axis scale factor) otherwise.	X

EXPRESS Specification

ENTITY IfcCartesianTransformationOperator2DnonUniform
 SUBTYPE OF (IfcCartesianTransformationOperator2D);
  Scale2 : OPTIONAL IfcReal;
 DERIVE
  Scl2 : IfcReal := NVL(Scale2, SELFIfcCartesianTransformationOperator.Scl);
 WHERE
  Scale2GreaterZero : Scl2 > 0.0;
END_ENTITY;