#### IfcSurface

Natural language names

##### Semantic definitions at the entity

Entity definition

Definition from ISO/CD 10303-42:1992: A surface can be envisioned as a set of connected points in 3-dimensional space which is always locally 2-dimensional, but need not be a manifold.

> NOTE Corresponding STEP entity: surface, the following subtypes have been incorporated into IFC - elementary_surface (as IfcElementarySurface), swept_surface (as IfcSweptSurface) and bounded_surface (as IfcBoundedSurface). Please refer to ISO/IS 10303-42:1994, p. 68 for the final definition of the formal standard.

> HISTORY New class in IFC Release 1.5

Informal proposition:

1. A surface has non zero area.
2. A surface is arcwise connected.

##### Inherited definitions from supertypes

Entity inheritance
Attribute inheritance

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

##### Formal representations

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

EXPRESS-G diagram

`

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