IfcAdvancedFace

BACnet MVD

#### IfcAdvancedFace

Natural language names

| Fläche - komplex
| Advanced Face
| Face avancée

Change log

Item | SPF | XML | Change | Description
--- | --- | --- | --- | ---
IFC2x3 to IFC4
IfcAdvancedFace |  |  | ADDED |
IFC4 Addendum 1
IfcAdvancedFace |  |  |  |
SameSense |  |  | MODIFIED | Type changed from BOOLEAN to IfcBoolean.

##### Semantic definitions at the entity

Entity definition

An advanced face is a specialization of a face surface that has to meet requirements on using particular topological and geometric representation items for the definition of the faces, edges and vertices.

An IfcAdvancedFace is restricted to:

- have a face surface geometry of type IfcElementarySurface, IfcSweptSurface or IfcBSplineSurface,
- have one IfcFaceOuterBound as the bound of the face, with the exception of closed surfaces,
- have all faces to be bound by IfcEdgeLoop or IfcVertexLoop,
- have all edges to have an edge curve geometry,
- have the edge curve geometry restricted to IfcLine, IfcConic, IfcPolyline, or IfcBSplineCurve

In case of closed faces with periodic surfaces, such as cylindrical or spherical surfaces, the following applies:

- the edges of the closed surface, in case of a cylindrical surface the upper and lower cap, refer to the same instance of IfcVertexPoint twice,
- no IfcFaceOuterBound is provided, or the IfcFaceOuterBound is constructed using an IfcSeamCurve at the periodic end of the underlying closed surface, in case of a cylindrical surface at 0./360. degree.

Figure 384 — Use of IfcCylindricalSurface as underlying surface of an IfcAdvancedFace

> NOTE Entity adapted from advanced_face defined in ISO 10303-511.

> HISTORY New entity in IFC4

Formal Propositions

Rule | Description
--- | ---
ApplicableSurface | The geometry used in the definition of the face shall be restricted. The face geometry shall be an IfcElementarySurface, IfcSweptSurface, or IfcBSplineSurface.
RequiresEdgeCurve | The geometry of all bounding edges of the face shall be fully defined as IfcEdgeCurve's.
ApplicableEdgeCurves | The types of curve used to define the geometry of edges shall be restricted to IfcLine, IfcConic, IfcPolyline, or IfcBSplineCurve.

##### Inherited definitions from supertypes

Entity inheritance
Attribute inheritance

# | Attribute | Type | Cardinality | Description | B
--- | --- | --- | --- | --- | ---
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.

> 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

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.

> IFC2x3 CHANGE The inverse attribute StyledByItem has been added.

X

X

IfcTopologicalRepresentationItem
IfcFace
1 | Bounds | IfcFaceBound | S[1:?] | Boundaries of the face. | X | X
| HasTextureMaps | IfcTextureMap @MappedTo | S[0:?] |  |  | X
IfcFaceSurface
2 | FaceSurface | IfcSurface |  | The surface which defines the internal shape of the face. This surface may be unbounded. The domain of the face is defined by this surface and the bounding loops in the inherited attribute SELF\FaceBounds. | X | X
3 | SameSense | IfcBoolean |  | This flag indicates whether the sense of the surface normal agrees with (TRUE), or opposes (FALSE), the sense of the topological normal to the face. | X | X
IfcAdvancedFace

##### Formal representations

XML Specification
`<xs:element name="IfcAdvancedFace" type="ifc:IfcAdvancedFace" substitutionGroup="ifc:IfcFaceSurface" nillable="true"/>
<xs:complexType name="IfcAdvancedFace">
<xs:complexContent>
<xs:extension base="ifc:IfcFaceSurface"/>
</xs:complexContent>
</xs:complexType>
`
EXPRESS Specification
`ENTITY IfcAdvancedFace
SUBTYPE OF (IfcFaceSurface);
WHERE
ApplicableSurface : SIZEOF (
['IFCGEOMETRYRESOURCE.IfcElementarySurface',
'IFCGEOMETRYRESOURCE.IfcSweptSurface',
'IFCGEOMETRYRESOURCE.IfcBSplineSurface'] *
TYPEOF(SELF\IfcFaceSurface.FaceSurface)) = 1;
RequiresEdgeCurve : SIZEOF(QUERY (ElpFbnds <*
QUERY (Bnds <* SELF\IfcFace.Bounds |
'IFCTOPOLOGYRESOURCE.IfcEdgeLoop' IN TYPEOF(Bnds.Bound)) |
NOT (SIZEOF (QUERY (Oe <* ElpFbnds.Bound\IfcEdgeLoop.EdgeList |
NOT('IFCTOPOLOGYRESOURCE.IfcEdgeCurve' IN
TYPEOF(Oe\IfcOrientedEdge.EdgeElement)
))) = 0
))) = 0;
ApplicableEdgeCurves : SIZEOF(QUERY (ElpFbnds <*
QUERY (Bnds <* SELF\IfcFace.Bounds |
'IFCTOPOLOGYRESOURCE.IfcEdgeLoop' IN TYPEOF(Bnds.Bound)) |
NOT (SIZEOF (QUERY (Oe <* ElpFbnds.Bound\IfcEdgeLoop.EdgeList |
NOT (SIZEOF (['IFCGEOMETRYRESOURCE.IfcLine',
'IFCGEOMETRYRESOURCE.IfcConic',
'IFCGEOMETRYRESOURCE.IfcPolyline',
'IFCGEOMETRYRESOURCE.IfcBSplineCurve'] *
TYPEOF(Oe\IfcOrientedEdge.EdgeElement\IfcEdgeCurve.EdgeGeometry)) = 1 )
)) = 0
))) = 0;
END_ENTITY;

EXPRESS-G diagram

`

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