IFC 4.3.x development

8.8.3.18 IfcFacetedBrepWithVoids

Change log

IFC4

modificationssupertypeChanged from IfcManifoldSolidBrep to IfcFacetedBrep

8.8.3.18.1 Semantic definitions at the entity

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:

  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 bounding loops of all the faces of all the shells in the IfcFacetedBrep shall be of type IfcPolyLoop.

8.8.3.18.1 Attributes

# Attribute Type Description
IfcRepresentationItem
LayerAssignmentSET [0:1] OF IfcPresentationLayerAssignment FOR AssignedItemsAssignment 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.
StyledByItem SET [0:1] OF IfcStyledItem FOR 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.



> IFC2x3 CHANGE  The inverse attribute StyledByItem has been added.
IfcGeometricRepresentationItem
IfcSolidModel
Dim INVALID 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 SET [1:?] OF IfcClosedShell Set of closed shells defining voids within the solid.

8.8.3.18.2 Entity inheritance

dot_inheritance IfcFacetedBrepWithVoids IfcFacetedBrepWithVoids IfcFacetedBrep IfcFacetedBrep IfcFacetedBrepWithVoids->IfcFacetedBrep IfcManifoldSolidBrep IfcManifoldSolidBrep IfcFacetedBrep->IfcManifoldSolidBrep IfcAdvancedBrep IfcAdvancedBrep IfcAdvancedBrep->IfcManifoldSolidBrep IfcSolidModel IfcSolidModel IfcManifoldSolidBrep->IfcSolidModel IfcSolidModel_children 4 more... IfcSolidModel_children->IfcSolidModel IfcGeometricRepresentationItem IfcGeometricRepresentationItem IfcSolidModel->IfcGeometricRepresentationItem IfcGeometricRepresentationItem_children 24 more... IfcGeometricRepresentationItem_children->IfcGeometricRepresentationItem IfcRepresentationItem IfcRepresentationItem IfcGeometricRepresentationItem->IfcRepresentationItem IfcRepresentationItem_children 3 more... IfcRepresentationItem_children->IfcRepresentationItem

8.8.3.18.3 Formal representations

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