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IfcCircle

时间:2020-07-08 20:04:47      阅读:76      评论:0      收藏:0      [点我收藏+]

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ifccirel是由一组与中心距离相等的点组成的曲线。

注:圆弧段是通过使用IFCTrimedCurve定义的,BasicCurve是一个IFCCIRE。

下图说明了放置在元素对象坐标系内的三维位置坐标系中IfcCircle的定义。

技术图片

 


注:定义根据ISO/CD 10303-42:1992

圆由半径、圆的位置和方向定义。数据解释如下:

C = SELF\IfcConic.Position.Location
x = SELF\IfcConic.Position.P[1]
y = SELF\IfcConic.Position.P[2]
z = SELF\IfcConic.Position.P[3]
R = Radius

 

圆参数化:

技术图片

 

 

参数化范围为0≤u≤2π(0≤u≤360度)。

在上面定义的放置坐标系中,圆是方程C=0,其中

技术图片

 

圆在任何一点的正方向都在该点曲线的切线方向T上,其中

技术图片

 

注:实体改编自ISO 10303-42中定义的圆圈

IFC1.0中增加的新实体

 

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
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
IfcConic
1 Position IfcAxis2Placement [1:1] The location and orientation of the conic. Further details of the interpretation of this attribute are given for the individual subtypes." X
IfcCircle
2 Radius IfcPositiveLengthMeasure [1:1] The radius of the circle, which shall be greater than zero. X
EXPRESS Specification
ENTITY IfcCircle
 SUBTYPE OF (IfcConic);
  Radius : IfcPositiveLengthMeasure;
END_ENTITY;

 

IfcCircle

标签:car   present   解释   lsp   cst   cbo   style   represent   nes   

原文地址:https://www.cnblogs.com/herd/p/13268488.html

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