IfcObjectPlacement

IfcObjectPlacement

实体定义

IfcObjectPlacement是定义对象坐标系的特殊类型的抽象超类型。必须为具有形状表示的每个产品提供IfcObjectPlacement。

可以给出对象放置：

绝对：通过相对于世界坐标系的axis2放置，

相对：通过axis2放置，相对于另一产品的对象放置，

通过网格参照：通过设计网格的两个轴给出的虚拟交点和参照方向。

在任何情况下，对象放置必须明确地将对象坐标系定义为二维轴放置（IfcAxis2Placement2D）或三维轴放置（IFcaxis2Placement 3D）。可能必须计算轴位置。

IFC2x中的新实体。

Attribute inheritance

#	Attribute	Type	Cardinality	Description	C
IfcObjectPlacement
	PlacesObject	IfcProduct @ObjectPlacement	S[0:?]	The IfcObjectPlacement shall be used to provide a placement and an object coordinate system for instances of IfcProduct. If an IfcObjectPlacement is shared by many instances of IfcProduct it does not apply a semantic meaning of being a shared placement that needs to be maintained. The same instance of IfcObjectPlacement could simply be used to reduce exchange file size.	X
	ReferencedByPlacements	IfcLocalPlacement @PlacementRelTo	S[0:?]	Placements that are given relative to this placement of an object.	X

 

EXPRESS Specification

ENTITY IfcObjectPlacement
 ABSTRACT SUPERTYPE OF(ONEOF(IfcGridPlacement, IfcLocalPlacement));
 INVERSE
  PlacesObject : SET [0:?] OF IfcProduct FOR ObjectPlacement;
  ReferencedByPlacements : SET OF IfcLocalPlacement FOR PlacementRelTo;
END_ENTITY;

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