#### IfcFacetedBrep

Natural language names

##### Semantic definitions at the entity

Entity definition

Definition from ISO/CD 10303-42:1992: A faceted brep 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 Brep.

> NOTE: The faceted brep has been introduced in order to support the larger number of systems that allow boundary type solid representations with planar surfaces only.

> NOTE: Corresponding STEP entity: faceted_brep. Please refer to ISO/IS 10303-42:1994, p. 173 for the final definition of the formal standard. In the current IFC Release faceted B-rep with voids is represented by an own subtype and not defined via an implicit ANDOR supertype constraint as in ISO/IS 10303-42:1994. This change has been made due to the fact, that only ONEOF supertype constraint is allowed within the IFC object model.

> HISTORY New class in IFC Release 1.0

Informal proposition:

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

##### Inherited definitions from supertypes

Entity inheritance
Attribute inheritance

# | Attribute | Type | Cardinality | Description | A
--- | --- | --- | --- | --- | ---
IfcRepresentationItem
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

##### Formal representations

XSD Specification
`<xs:element name="IfcFacetedBrep" type="ifc:IfcFacetedBrep" substitutionGroup="ifc:IfcManifoldSolidBrep" nillable="true"/>
<xs:complexType name="IfcFacetedBrep">
<xs:complexContent>
<xs:extension base="ifc:IfcManifoldSolidBrep"/>
</xs:complexContent>
</xs:complexType>
`
EXPRESS Specification
`ENTITY IfcFacetedBrep
SUBTYPE OF (IfcManifoldSolidBrep);
END_ENTITY;

EXPRESS-G diagram

`

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