标签：car present 解释 lsp cst cbo style represent nes
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。
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:
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
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
注：实体改编自ISO 10303-42中定义的圆圈
IFC1.0中增加的新实体
| # | 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 | |
| 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 |
ENTITY IfcCircle
SUBTYPE OF (IfcConic);
Radius : IfcPositiveLengthMeasure;
END_ENTITY;
标签：car present 解释 lsp cst cbo style represent nes
原文地址：https://www.cnblogs.com/herd/p/13268488.html
