IfcSurface

Natural language names
Oberfläche
Surface
Surface
Semantic definitions at the entity
Entity definition

An IfcSurface is a 2-dimensional representation item positioned in 3-dimensional space. 2-dimensional means that each point at the surface can be defined by a 2-dimensional coordinate system, usually by u and v coordinates.

NOTE  Definition according to 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  Entity adapted from surface defined in ISO 10303-42.

HISTORY  New entity in IFC1.5

Informal Propositions:

  1. A surface has non zero area.
  2. A surface is arcwise connected.
Attribute definitions
#AttributeTypeCardinalityDescription G
Dim
:=3
IfcDimensionCountThe space dimensionality of IfcSurface. It is always a three-dimensional geometric representation item.
IFC4 CHANGE Derived attribute promoted from subtypes.
X
Inherited definitions from supertypes
Entity inheritance IfcBoundedSurface IfcElementarySurface IfcSectionedSurface IfcSweptSurface IfcGeometricRepresentationItem IfcRepresentationItem
Attribute inheritance
#AttributeTypeCardinalityDescriptionG
IfcRepresentationItem
LayerAssignmentIfcPresentationLayerAssignment
@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
StyledByItemIfcStyledItem
@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
IfcGeometricRepresentationItem
IfcSurface
Dim
:=3
IfcDimensionCountThe space dimensionality of IfcSurface. It is always a three-dimensional geometric representation item.
IFC4 CHANGE Derived attribute promoted from subtypes.
X
Formal representations
XML 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
 ABSTRACT SUPERTYPE OF(ONEOF(IfcBoundedSurface, IfcElementarySurface, IfcSectionedSurface, IfcSweptSurface))
 SUBTYPE OF (IfcGeometricRepresentationItem);
 DERIVE
  Dim : IfcDimensionCount := 3;
END_ENTITY;

Link to EXPRESS-G diagram EXPRESS-G diagram

References  References: IfcSurfaceOrFaceSurface IfcHalfSpaceSolid IfcSurfaceCurveSweptAreaSolid IfcGeometricSetSelect IfcCompositeCurveOnSurface IfcCurveBoundedSurface IfcPcurve IfcPointOnSurface IfcRectangularTrimmedSurface IfcSurfaceCurve IfcFaceSurface

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