IfcTessellatedFaceSet

Natural language names
detesselliertes Element aus Flächen
enTessellated Face Set
frEnsemble de faces tessellées
Change log
ItemSPFXMLChangeDescription
IFC2x3 to IFC4
    IfcTessellatedFaceSetADDED
Semantic definitions at the entity
Entity definition

The IfcTessellatedFaceSet is a boundary representation topological model limited to planar faces and straight edges. It may represent an approximation of an analytical surface or solid that may be provided in addition to its tessellation as a separate shape representation. The IfcTessellatedFaceSet provides a compact data representation of an connected face set using indices into ordered lists of vertices, normals, colours, and texture maps.

NOTE  The compact representation has been chosen to enable small data sets despite potentially large sets of faces, edges and vertices needed to represent tessellations of analyticals surfaces and solids, and despite large sets of colour and texture information to annotate the tessellated faces.

The IfcTessellatedFaceSet is an abstract supertype of tesselated face sets each imposing specific constraints on face generation for tessellation, such as triangulation (with or without strip and fans), or quadrilaterals.

NOTE  Not all different constraints on face sets are included as specific subtypes in this release of the specification.

The following attributes apply to all subtypes:

Each face of the tessellated face set shall have:

NOTE  The definition of IfcTessellatedFaceSet is based on the indexedFaceSet defined in ISO/IEC 19775-1
HISTORY  New entity in IFC4.
Attribute definitions
#AttributeTypeCardinalityDescription C
1CoordinatesIfcCartesianPointList3D[1:1] An ordered list of Cartesian points used by the coordinate index defined at the subtypes of IfcTessellatedFaceSet.X
2NormalsIfcParameterValueL[1:?]L[3:3] An ordered list of directions used by the normal index defined at the subtypes of IfcTessellatedFaceSet. It is a two-dimensional list of directions provided by three parameter values.X
3ClosedIfcBoolean[0:1] Indication whether the IfcTessellatedFaceSet is a closed shell or not. If omited no such information can be provided.X
HasColoursIfcIndexedColourMap
@MappedTo
S[0:1]Reference to the indexed colour map providing the corresponding colour RGB values to the faces of the subtypes of IfcTessellatedFaceSet.X
HasTexturesIfcIndexedTextureMap
@MappedTo
S[0:?]Reference to the indexed texture map providing the corresponding texture coordinates to the vertices bounding the faces of the subtypes of IfcTessellatedFaceSet.X
Inherited definitions from supertypes
Entity inheritance IfcTriangulatedFaceSet IfcTessellatedItem IfcGeometricRepresentationItem IfcRepresentationItem
Attribute inheritance
#AttributeTypeCardinalityDescriptionC
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. 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. X
IfcGeometricRepresentationItem
IfcTessellatedItem
IfcTessellatedFaceSet
1CoordinatesIfcCartesianPointList3D[1:1] An ordered list of Cartesian points used by the coordinate index defined at the subtypes of IfcTessellatedFaceSet.X
2NormalsIfcParameterValueL[1:?]L[3:3] An ordered list of directions used by the normal index defined at the subtypes of IfcTessellatedFaceSet. It is a two-dimensional list of directions provided by three parameter values.X
3ClosedIfcBoolean[0:1] Indication whether the IfcTessellatedFaceSet is a closed shell or not. If omited no such information can be provided.X
HasColoursIfcIndexedColourMap
@MappedTo
S[0:1]Reference to the indexed colour map providing the corresponding colour RGB values to the faces of the subtypes of IfcTessellatedFaceSet.X
HasTexturesIfcIndexedTextureMap
@MappedTo
S[0:?]Reference to the indexed texture map providing the corresponding texture coordinates to the vertices bounding the faces of the subtypes of IfcTessellatedFaceSet.X
Formal representations
XSD Specification
 <xs:element name="IfcTessellatedFaceSet" type="ifc:IfcTessellatedFaceSet" abstract="true" substitutionGroup="ifc:IfcTessellatedItem" nillable="true"/>
 <xs:complexType name="IfcTessellatedFaceSet" abstract="true">
  <xs:complexContent>
   <xs:extension base="ifc:IfcTessellatedItem">
    <xs:sequence>
     <xs:element name="Coordinates" type="ifc:IfcCartesianPointList3D" nillable="true"/>
     <xs:element name="HasColours" type="ifc:IfcIndexedColourMap" nillable="true" minOccurs="0" maxOccurs="1"/>
     <xs:element name="HasTextures" nillable="true" minOccurs="0">
      <xs:complexType>
       <xs:sequence>
        <xs:element ref="ifc:IfcIndexedTextureMap" minOccurs="0" maxOccurs="unbounded"/>
       </xs:sequence>
       <xs:attribute ref="ifc:itemType" fixed="ifc:IfcIndexedTextureMap"/>
       <xs:attribute ref="ifc:cType" fixed="set"/>
       <xs:attribute ref="ifc:arraySize" use="optional"/>
      </xs:complexType>
     </xs:element>
    </xs:sequence>
    <xs:attribute name="Normals" use="optional">
     <xs:simpleType>
      <xs:restriction>
       <xs:simpleType>
        <xs:list itemType="ifc:IfcParameterValue"/>
       </xs:simpleType>
       <xs:minLength value="3"/>
      </xs:restriction>
     </xs:simpleType>
    </xs:attribute>
    <xs:attribute name="Closed" type="ifc:IfcBoolean" use="optional"/>
   </xs:extension>
  </xs:complexContent>
 </xs:complexType>
EXPRESS Specification
ENTITY IfcTessellatedFaceSet
 ABSTRACT SUPERTYPE OF(IfcTriangulatedFaceSet)
 SUBTYPE OF (IfcTessellatedItem);
  Coordinates : IfcCartesianPointList3D;
  Normals : OPTIONAL LIST [1:?] OF LIST [3:3] OF IfcParameterValue;
  Closed : OPTIONAL IfcBoolean;
 INVERSE
  HasColours : SET [0:1] OF IfcIndexedColourMap FOR MappedTo;
  HasTextures : SET [0:?] OF IfcIndexedTextureMap FOR MappedTo;
END_ENTITY;

Link to EXPRESS-G diagram EXPRESS-G diagram

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