IfcSurfaceOfRevolution

Posted 2020-12-21 herd

IfcSurfaceOfRevolution是通过绕轴旋转曲线而得到的曲面。

注：定义根据ISO/CD 10303-42:1992

旋转曲面是将曲线绕轴旋转一整圈而得到的曲面。数据解释如下。

参数化如下，其中曲线具有参数化λ（u）：

C = AxisPosition.Location
V = AxisPosition.Z

 

 

为了产生一个完整旋转的单值曲面，曲线应确保当以圆柱坐标系表示时，曲线应在以C为中心、V轴为中心的圆柱坐标系（r，φ，z）中表示时，曲线上的两个不同参数点的（r，z） 一。对于旋转曲面，参数范围为0<u<360度。v的参数化范围由参考曲线定义。

注：实体改编自ISO 10303-42中定义的旋转表面。

IFC2x中的历史新实体。

非正式提议：

表面不得自相交

扫掠曲线在其长度的任何有限部分不得与轴线重合。

 

 

 

 

#	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
IfcSurface
	Dim :=3	IfcDimensionCount	[1:1]	The space dimensionality of IfcSurface. It is always a three-dimensional geometric representation item.	X
IfcSweptSurface
1	SweptCurve	IfcProfileDef	[1:1]	The curve to be swept in defining the surface. The curve is defined as a profile within the position coordinate system.	X
2	Position	IfcAxis2Placement3D	[0:1]	Position coordinate system for the swept surface, provided by a profile definition within the XY plane of the Position coordinates. If not provided, the position of the profile being swept is determined by the object coordinate system. In this case, the swept surface is not repositioned.	X
IfcSurfaceOfRevolution
3	AxisPosition	IfcAxis1Placement	[1:1]	A point on the axis of revolution and the direction of the axis of revolution.	X
	AxisLine :=IfcRepresentationItem() || IfcGeometricRepresentationItem () || IfcCurve() || IfcLine(AxisPosition.Location, IfcRepresentationItem() || IfcGeometricRepresentationItem () || IfcVector(AxisPosition.Z,1.0))	IfcLine	[1:1]	The line coinciding with the axis of revolution.	X

 

EXPRESS Specification

ENTITY IfcSurfaceOfRevolution
 SUBTYPE OF (IfcSweptSurface);
  AxisPosition : IfcAxis1Placement;
 DERIVE
  AxisLine : IfcLine := IfcRepresentationItem() || IfcGeometricRepresentationItem () || IfcCurve() || IfcLine(AxisPosition.Location, IfcRepresentationItem() || IfcGeometricRepresentationItem () || IfcVector(AxisPosition.Z,1.0));
END_ENTITY;