IfcElementarySurface

BACnet MVD

#### IfcElementarySurface

Natural language names

| elementare Fläche
| Elementary Surface
| Surface élémentaire

##### Semantic definitions at the entity

Entity definition

An IfcElementarySurface in the common supertype of analytical surfaces.

> NOTE Definition according to ISO/CD 10303-42:1992
> An elementary surface (IfcElementarySurface) is a simple analytic surface with defined parametric representation.

> NOTE Entity adapted from elementary_surface defined in ISO 10303-42.

> HISTORY New entity in IFC1.5

Attribute definitions

# | Attribute | Type | Cardinality | Description | B
--- | --- | --- | --- | --- | ---
1 | Position | IfcAxis2Placement3D |  | The position and orientation of the surface. This attribute is used in the definition of the parameterization of the surface. | X | X

##### 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

IfcGeometricRepresentationItem
IfcSurface

Dim
:=3

IfcDimensionCount

The space dimensionality of IfcSurface. It is always a three-dimensional geometric representation item.

> IFC4 CHANGE Derived attribute promoted from subtypes.

X

X

IfcElementarySurface
1 | Position | IfcAxis2Placement3D |  | The position and orientation of the surface. This attribute is used in the definition of the parameterization of the surface. | X | X

##### Formal representations

XML Specification
`<xs:element name="IfcElementarySurface" type="ifc:IfcElementarySurface" abstract="true" substitutionGroup="ifc:IfcSurface" nillable="true"/>
<xs:complexType name="IfcElementarySurface" abstract="true">
<xs:complexContent>
<xs:extension base="ifc:IfcSurface">
<xs:sequence>
<xs:element name="Position" type="ifc:IfcAxis2Placement3D" nillable="true"/>
</xs:sequence>
</xs:extension>
</xs:complexContent>
</xs:complexType>
`
EXPRESS Specification
`ENTITY IfcElementarySurface
ABSTRACT SUPERTYPE OF(ONEOF(IfcCylindricalSurface, IfcPlane, IfcSphericalSurface, IfcToroidalSurface))
SUBTYPE OF (IfcSurface);
Position : IfcAxis2Placement3D;
END_ENTITY;

EXPRESS-G diagram

`

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