IfcFacetedBrepWithVoids

Semantic definitions at the entity

Entity definition

The IfcFacetedBrepWithVoids is a specialization of a faceted B-rep which contains one or more voids in its interior. The voids are represented as closed shells which are defined so that the shell normal point into the void.

NOTE Entity adapted from brep_with_voids AND faceted_brep defined in ISO 10303-42.

HISTORY New entity in IFC1.0

IFC4 CHANGE Subtyping changed from IfcManifoldSolidBrep to IfcFacetedBrep with upward compatibility for file based exchange.

Informal Propositions:

Each void shell shall be disjoint from the outer shell and from every other void shell
Each void shell shall be enclosed within the outer shell but not within any other void shell. In particular the outer shell is not in the set of void shells
Each shell in the IfcManifoldSolidBrep shall be referenced only once.
All the bounding loops of all the faces of all the shells in the IfcFacetedBrep shall be of type IfcPolyLoop.

Attribute definitions

#	Attribute	Type	Cardinality	Description	C
2	Voids	IfcClosedShell	S[1:?]	Set of closed shells defining voids within the solid.	X

Inherited definitions from supertypes

Entity inheritance

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
IfcManifoldSolidBrep
1	Outer	IfcClosedShell	[1:1]	A closed shell defining the exterior boundary of the solid. The shell normal shall point away from the interior of the solid.	X
IfcFacetedBrep
IfcFacetedBrepWithVoids
2	Voids	IfcClosedShell	S[1:?]	Set of closed shells defining voids within the solid.	X

Formal representations

XSD Specification

 <xs:element name="IfcFacetedBrepWithVoids" type="ifc:IfcFacetedBrepWithVoids" substitutionGroup="ifc:IfcFacetedBrep" nillable="true"/>

 <xs:complexType name="IfcFacetedBrepWithVoids">

  <xs:complexContent>

   <xs:extension base="ifc:IfcFacetedBrep">

    <xs:sequence>

     <xs:element name="Voids">

      <xs:complexType>

       <xs:sequence>

        <xs:element ref="ifc:IfcClosedShell" maxOccurs="unbounded"/>

       </xs:sequence>

       <xs:attribute ref="ifc:itemType" fixed="ifc:IfcClosedShell"/>

       <xs:attribute ref="ifc:cType" fixed="set"/>

       <xs:attribute ref="ifc:arraySize" use="optional"/>

      </xs:complexType>

     </xs:element>

    </xs:sequence>

   </xs:extension>

  </xs:complexContent>

 </xs:complexType>

EXPRESS Specification


ENTITY IfcFacetedBrepWithVoids

 SUBTYPE OF (IfcFacetedBrep);

  Voids : SET [1:?] OF IfcClosedShell;

END_ENTITY;

 EXPRESS-G diagram

	Facettierte Boundary Representation mit Aussparungen
	Faceted Brep With Voids