IfcFacetedBrepWithVoids

IfcFacetedBrepWithVoids是刻面B-rep的一個特化，它的内部包含一個或多個空洞。空隙被表示為閉合殼，這些殼被定義為使殼法線指向空洞。

注：實體根據ISO 10303-42中定義的brep_，帶有_空隙和鑲嵌面_brep。

IFC1.0中增加的新實體

IFC4 修改子類型從IfcManifoldSolidBrep更改為IfcFacetedBrep，具有對基于檔案的交換的向上相容性。

非正式提議：

①每個空殼應與外殼和其他空殼分離

②每個空心外殼應封閉在外殼内，而不是任何其他空心外殼内。尤其是外殼不在空殼組中

③IfcManifoldSolidBrep中的每個shell隻能引用一次。

④IfcFacetedBrep中所有殼體表面的所有邊界環應為IfcPolyLoop類型。

#	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		Reference to the ​​IfcStyledItem​​ that provides presentation information to the representation, e.g. a curve style, including colour and thickness to a geometric curve.
​​IfcGeometricRepresentationItem​​
​​IfcSolidModel​​
Dim :=3	​​IfcDimensionCount​​	[1:1]	The space dimensionality of this class, it is always 3.
​​IfcManifoldSolidBrep​​
1	Outer	​​IfcClosedShell​​		A closed shell defining the exterior boundary of the solid. The shell normal shall point away from the interior of the solid.
​​IfcFacetedBrep​​
​​IfcFacetedBrepWithVoids​​
2	Voids		S[1:?]	Set of closed shells defining voids within the solid.

EXPRESS Specification

ENTITY IfcFacetedBrepWithVoids
 SUBTYPE OF (IfcFacetedBrep);
  Voids : SET [1:?] OF IfcClosedShell;
END_ENTITY;