IfcMappedItem

IfcMappedItem是源定义的插入实例（与块/共享单元/宏定义进行比较）。通过应用笛卡尔变换操作符作为映射目标来插入实例。

注意映射项是表示项的子类型。它使一个表示可以用作一个或多个其他表示中的表示项。映射项允许使用其他表示来定义表示。

示例IfcMappedItem可以重用其他映射项（ako嵌套块），这样一来，IfcRepresentationMap基于包含一个或多个IfcMappedItem的ifcshapeerepresentation。

注：定义根据ISO/CD 10303-43:1992

映射项是一种表示项类型，它将表示的映射指定为第二个表示的项的元素。

注：实体改编自ISO 10303-43中定义的映射项。

IFC2x中增加的新实体。

非正式提议：

①映射项不得通过参与被映射表示的定义而进行自定义。

②如果映射源是一个几何表示项，则映射源和映射目标的维数必须相同。

#	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
IfcMappedItem
1	MappingSource	IfcRepresentationMap	[1:1]	A representation map that is the source of the mapped item. It can be seen as a block (or cell or marco) definition.	X
2	MappingTarget	IfcCartesianTransformationOperator	[1:1]	A representation item that is the target onto which the mapping source is mapped. It is constraint to be a Cartesian transformation operator.	X

 

EXPRESS Specification

ENTITY IfcMappedItem
 SUBTYPE OF (IfcRepresentationItem);
  MappingSource : IfcRepresentationMap;
  MappingTarget : IfcCartesianTransformationOperator;
END_ENTITY;