IfcExtrudedAreaSolidTapered
作者:互联网
实体定义
IfcExtrudedAreaSolidTaped是通过沿线性脊椎扫掠横截面来定义的。横截面可能会沿扫掠从起始横截面的形状变为结束横截面的形状。生成的实体由三个或多个面包围:开始面、结束面(每个面都由起始平面和结束平面及截面定义)以及一个或多个侧面。每个侧面是一个直纹面,由起始和结束截面的一对对应边定义。
注意,假设起点和终点截面由多边形提供,则起点和终点横截面的相应顶点是连接的,在每对对应顶点之间形成一个四边形多边形。边界四边形定义的曲面是直纹曲面,可以通过三角剖分来逼近。
线性脊椎定义如下:
起点:自我\IfcSweptAreaSolid.Position.位置
方向:自我\IfcExtrudedAreaSolid.ExtrudedDirection
距离:自我\IfcExtrudedAreaSolid.深度
起始横截面由SELF定义\IfcSweptAreaSolid.SweptArea:
位于由SELF定义的位置坐标系的XY平面上的有界平面\IfcSweptAreaSolid.位置.P[1]和SELF\IfcSweptAreaSolid.位置.P[2]
线性脊椎从起始横截面的平面开始。脊椎不一定垂直于平面。
端部横截面由端部截面积定义:
位于位置坐标系XY平面上的有界平面,通过转换SELF提供的起始位置坐标定义\IfcSweptAreaSolid.位置沿脊椎方向按脊椎距离。结束横截面的平面与起始横截面的平面共面。
结束横截面在拓扑上与起始横截面相似(即具有相同数量的顶点和边)。
端部横截面既可以由使用不同参数值的同一参数轮廓定义,也可以通过端部横截面平面内起始轮廓的二维笛卡尔变换来定义。
如果有两个参数化轮廓,则形状构造如下:
末端轮廓由基于与起始轮廓相同的轮廓参数化的横截面定义,通过沿脊椎方向的脊椎距离进行平移。
它可以在末端位置坐标系的XY平面内移动,也可以使用旋转参数进行扭曲。
偏移和旋转参数由端部横截面类型为IfcParameterizedProfileDef提供,其中
Shift is EndSweptArea\IfcParameterizedProfileDef.Position.Location
旋转为EndSweptArea\IfcParameterizedProfileDef.Position.RefDirection
起始和结束横截面的相应顶点是连接的。侧面被构造为起始和结束横截面的相应边之间的直纹曲面。
对于起始横截面的笛卡尔变换,形状构造如下:
横截面曲线从位置坐标系的XY平面中的曲线开始,首先通过比例参数围绕原点进行缩放。然后通过沿脊椎方向的脊椎距离进行平移。它可能被旋转参数扭曲了。
“缩放”和“旋转”参数由类型为IfcDerivedProfileDef的末端横截面提供,其中
刻度是末端\IfcDerivedProfileDef.Operator.Scale
旋转是结束区域\IfcDerivedProfileDef.Operator.Axis1
起始和结束横截面的相应顶点是连接的。侧面被构造为起始和结束横截面的相应边之间的直纹曲面。
IFC4中的历史新实体。
非正式提议:
内部镜像IfcDerivedProfileDef.运算符不得使用
Formal Propositions
Rule | Description |
---|---|
CorrectProfileAssignment | The SweptArea as start profile and the EndSweptArea as end profile shall be compatible. |
Attribute inheritance
# | 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 | |||||
IfcSolidModel | |||||
Dim :=3 |
IfcDimensionCount | [1:1] | The space dimensionality of this class, it is always 3. | X | |
IfcSweptAreaSolid | |||||
1 | SweptArea | IfcProfileDef | [1:1] | The surface defining the area to be swept. It is given as a profile definition within the xy plane of the position coordinate system. | X |
2 | Position | IfcAxis2Placement3D | [0:1] | Position coordinate system for the resulting swept solid of the sweeping operation. The position coordinate system allows for re-positioning of the swept solid. If not provided, the swept solid remains within the position as determined by the cross section or by the directrix used for the sweeping operation. | X |
IfcExtrudedAreaSolid | |||||
3 | ExtrudedDirection | IfcDirection | [1:1] | The direction in which the surface, provided by SweptArea is to be swept. | X |
4 | Depth | IfcPositiveLengthMeasure | [1:1] | The distance the surface is to be swept along the ExtrudedDirection. | X |
IfcExtrudedAreaSolidTapered | |||||
5 | EndSweptArea | IfcProfileDef | [1:1] | The surface defining the end of the swept area. It is given as a profile definition. The position coordinate system of the EndSwptArea is generated by translating the SELF\IfcSweptAreaSolid.Position along the SELF\IfcExtrudedAreaSolid.ExtrudedDirection by the distance of SELF\IfcExtrudedAreaSolid.Depth. | X |
EXPRESS Specification
ENTITY IfcExtrudedAreaSolidTapered SUBTYPE OF (IfcExtrudedAreaSolid); EndSweptArea : IfcProfileDef; WHERE CorrectProfileAssignment : IfcTaperedSweptAreaProfiles(SELF\IfcSweptAreaSolid.SweptArea, SELF.EndSweptArea); END_ENTITY;
标签:IfcSweptAreaSolid,SELF,起始,脊椎,平面,横截面,IfcExtrudedAreaSolidTapered 来源: https://www.cnblogs.com/herd/p/13620599.html