IfcCartesianTransformationOperator3DnonUniform

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笛卡尔变换算子3d-non-uniform定义了由平移、旋转、镜像和非均匀缩放组成的三维空间中的几何变换。非均匀缩放由三个不同的缩放因子给出:

①自我IfcCartesianTransformationOperator.Scale:x轴比例因子

②Scale2:y轴比例因子

③Scale3:z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或Scale3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中记录新实体。

Formal Propositions

RuleDescription
Scale2GreaterZero The derived scaling Scl2 shall be greater than zero.
Scale3GreaterZero The derived scaling Scl3 shall be greater than zero.
 

 

 

技术图片

 

 

#AttributeTypeCardinalityDescriptionC
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
IfcCartesianTransformationOperator3D
5 Axis3 IfcDirection [0:1] The exact direction of U[3], the derived Z axis direction. X
  U
:=IfcBaseAxis(3,SELFIfcCartesianTransformationOperator.Axis1, SELFIfcCartesianTransformationOperator.Axis2,Axis3)
IfcDirection L[3:3] The list of mutually orthogonal, normalized vectors defining the transformation matrix T. They are derived from the explicit attributes Axis3, Axis1, and Axis2 in that order. X
IfcCartesianTransformationOperator3DnonUniform
6 Scale2 IfcReal [0:1] The scaling value specified for the transformation along the axis 2. This is normally the y scale factor. X
7 Scale3 IfcReal [0:1] The scaling value specified for the transformation along the axis 3. This is normally the z 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
  Scl3
:=NVL(Scale3, SELFIfcCartesianTransformationOperator.Scl)
IfcReal [1:1] The derived scale S(3) of the transformation along the axis 3 (normally the z axis), equal to Scale3 if that exists, or equal to the derived Scl1 (normally the x axis scale factor) otherwise. X
EXPRESS Specification
ENTITY IfcCartesianTransformationOperator3DnonUniform
 SUBTYPE OF (IfcCartesianTransformationOperator3D);
  Scale2 : OPTIONAL IfcReal;
  Scale3 : OPTIONAL IfcReal;
 DERIVE
  Scl2 : IfcReal := NVL(Scale2, SELFIfcCartesianTransformationOperator.Scl);
  Scl3 : IfcReal := NVL(Scale3, SELFIfcCartesianTransformationOperator.Scl);
 WHERE
  Scale2GreaterZero : Scl2 > 0.0;
  Scale3GreaterZero : Scl3 > 0.0;
END_ENTITY;

 

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