IfcShellBasedSurfaceModel[操作系统入门]
IfcShellBasedSurfaceModel通过一组开放或闭合的壳来表示形状。壳内的连接面具有维数2,并且放置在维度3的坐标空间中。
注:定义根据ISO/CD 10303-42:1992
基于壳的曲面模型由一组维数为2的开壳或闭壳来描述。除边缘和顶点外,壳体不得相交。特别是,不同的面可能不相交。一个壳的完整面可以与另一个壳共享。壳体的重合部分应参考定义重合区域的相同面、边和顶点。至少应有一个外壳。壳可以独立于曲面模型而存在。
注:实体改编自ISO 10303-42中定义的基于外壳的表面模型。
IFC2x中增加的新实体。
非正式提议:
●基于壳的曲面模型的维数为2。
●壳体不得重叠或相交,除非在公共面、边或顶点处。
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
IfcShellBasedSurfaceModel
1
SbsmBoundary
IfcShell
S[1:?]
X
Dim
:=3
IfcDimensionCount
[1:1]
The space dimensionality of this class, it is always 3.
X
EXPRESS Specification
ENTITY IfcShellBasedSurfaceModel SUBTYPE OF (IfcGeometricRepresentationItem);
SbsmBoundary : SET [1:?] OF IfcShell;
DERIVE
Dim : IfcDimensionCount := 3;
END_ENTITY;
IfcShellBasedSurfaceModel
原文:https://www.cnblogs.com/herd/p/13432477.html
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