IfcCurve

IfcCurve是二维或三维空间中的曲线。它包括有界和无界曲线的定义。

注：根据ISO 10303-42的定义：

曲线可以想象为点在其坐标空间中移动的路径。

注：实体改编自ISO 10303-42中定义的曲线

在IFC1.0中增加的新实体

非正式提议：

■曲线应呈弧形连接

■曲线的弧长应大于零。

#	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
IfcCurve
	Dim :=IfcCurveDim(SELF)	IfcDimensionCount	[1:1]	The space dimensionality of this abstract class, defined differently for all subtypes, i.e. for IfcLine, IfcConic and IfcBoundedCurve.	X

EXPRESS Specification

ENTITY IfcCurve
 ABSTRACT SUPERTYPE OF(ONEOF(IfcBoundedCurve, IfcConic, IfcLine, IfcOffsetCurve2D, IfcOffsetCurve3D, IfcPcurve))
 SUBTYPE OF (IfcGeometricRepresentationItem);
 DERIVE
  Dim : IfcDimensionCount := IfcCurveDim(SELF);
END_ENTITY;