The IfcFacetedBrep is a manifold solid brep with the restriction that all faces are planar and bounded polygons.
NOTE Use of IfcFacetedBrep is restricted for boundary representation models with planar surfaces only. Those surfaces are implicitly represented by the bounding polygons. The diagram shows the topological and geometric representation items that are used for faceted breps.
Figure 1 — Diagram showing the use of IfcFacetedBrep
NOTE Definition according to ISO/CD 10303-42:1992
A faceted B-rep is a simple form of boundary representation model in which all faces are planar and all edges are straight lines. Unlike the B-rep model, edges and vertices are not represented explicitly in the model but are implicitly available through the poly loop entity. A faceted B-rep has to meet the same topological constraints as the manifold solid B-rep.
The faceted B-rep has been introduced in order to support the larger number of systems that allow boundary type solid representations with planar surfaces only.
NOTE Entity adapted from manifold_solid_brep defined in ISO 10303-42.
HISTORY New entity in IFC1.0
|LayerAssignment||SET [0:1] OF IfcPresentationLayerAssignment FOR AssignedItems||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.
|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.
|Dim||INVALID||The space dimensionality of this class, it is always 3.|
|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.|
ENTITY IfcFacetedBrep SUPERTYPE OF (ONEOF (IfcFacetedBrepWithVoids)) SUBTYPE OF (IfcManifoldSolidBrep); END_ENTITY;