IfcAdvancedBrepWithVoids

Natural language names
Boundary Representation mit Aussparungen - NURBS
Advanced Brep With Voids
Représentation frontière avancée avec trous
Change log
ItemSPFXMLChangeDescription
IFC2x3 to IFC4 4.0.0.0
    IfcAdvancedBrepWithVoidsADDED
Semantic definitions at the entity
Entity definition

The IfcAdvancedBrepWithVoids is a specialization of an advanced 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 advanced_brep_shape_representation defined in ISO 10303-42.

HISTORY  New entity in IFC4

Informal Propositions:

  1. Each void shell shall be disjoint from the outer shell and from every other void shell
  2. 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
  3. Each shell in the IfcManifoldSolidBrep shall be referenced only once.
  4. All the faces of all the shells in the IfcAdvancedBrep and the IfcAdvancedBrepWithVoids.Voids shall be of type IfcAdvancedFace.
Attribute definitions
#AttributeTypeCardinalityDescription G
2VoidsIfcClosedShellS[1:?] X
Formal Propositions
RuleDescription
VoidsHaveAdvancedFacesEach face of the voids within the advanced B-rep with voids shall be of type IfcAdvancedFace.
Inherited definitions from supertypes
Entity inheritance IfcAdvancedBrep IfcManifoldSolidBrep IfcSolidModel IfcGeometricRepresentationItem IfcRepresentationItem
Attribute inheritance
#AttributeTypeCardinalityDescriptionG
IfcRepresentationItem
LayerAssignmentIfcPresentationLayerAssignment
@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.
IFC2x3 CHANGE  The inverse attribute LayerAssignments has been added.
IFC4 CHANGE  The inverse attribute LayerAssignment has been restricted to max 1. Upward compatibility for file based exchange is guaranteed.
X
StyledByItemIfcStyledItem
@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.
IFC2x3 CHANGE  The inverse attribute StyledByItem has been added.
X
IfcGeometricRepresentationItem
IfcSolidModel
Dim
:=3
IfcDimensionCountThe space dimensionality of this class, it is always 3. X
IfcManifoldSolidBrep
1OuterIfcClosedShell A closed shell defining the exterior boundary of the solid. The shell normal shall point away from the interior of the solid. X
IfcAdvancedBrep
IfcAdvancedBrepWithVoids
2VoidsIfcClosedShellS[1:?] X
Formal representations
XML Specification
 <xs:element name="IfcAdvancedBrepWithVoids" type="ifc:IfcAdvancedBrepWithVoids" substitutionGroup="ifc:IfcAdvancedBrep" nillable="true"/>
 <xs:complexType name="IfcAdvancedBrepWithVoids">
  <xs:complexContent>
   <xs:extension base="ifc:IfcAdvancedBrep">
    <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 IfcAdvancedBrepWithVoids
 SUBTYPE OF (IfcAdvancedBrep);
  Voids : SET [1:?] OF IfcClosedShell;
 WHERE
  VoidsHaveAdvancedFaces : SIZEOF (QUERY (Vsh <* Voids |
SIZEOF (QUERY (Afs <* Vsh.CfsFaces |
(NOT ('IFCTOPOLOGYRESOURCE.IfcAdvancedFace' IN TYPEOF(Afs)))
)) = 0
)) = 0;
END_ENTITY;

Link to EXPRESS-G diagram EXPRESS-G diagram

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