IfcIndexedColourMap

Natural language names
Liste von Indizes für Farbwerte
Indexed Colour Map
Change log
ItemSPFXMLChangeDescription
IFC2x3 to IFC4 4.0.0.0
    IfcIndexedColourMapADDED
IFC4 Addendum 1 4.0.1.0
    IfcIndexedColourMap
      OpacityXXMODIFIEDName changed from Overrides to Opacity.
Type changed from IfcSurfaceStyleShading to IfcNormalisedRatioMeasure.
      ColourIndexMODIFIEDType changed from INTEGER to IfcPositiveInteger.
IFC4 Addendum 2 4.0.2.0
    IfcIndexedColourMap
      OpacityXMODIFIEDXsdformat changed from Attribute to Content.
IFC4X3_ADD2 to IFC4X4_draft
    IfcIndexedColourMap
      MappedToXXMODIFIEDType changed from IfcTessellatedFaceSet to IfcTessellatedItem.
Semantic definitions at the entity
Entity definition

The IfcIndexedColourMap provides the assignment of colour information to individual faces. It is used for colouring faces of tessellated face sets. The IfcIndexedColourMap defines an index into an indexed list of colour information. The Colours are a two-dimensional list of colours provided by three RGB values. The ColourIndex attribute corresponds to the CoordIndex of the IfcTessellatedFaceSet defining the corresponding index list of faces. The Opacity attribute provides the alpha channel for all faces of the tessellated face set.

Figure 541 shows the use of IfcTriangulatedFaceSet with colours per face.

"IfcIndexedColourMap_01"

Figure 541 — Indexed colour map

 

IfcIndexedColourMap_example-01

 

Figure 542 illustrates an IfcTriangulatedFaceSet represented by
  • IfcTriangulatedFaceSet.CoordIndex: ((1,6,5),(1,2,6), (6,2,7), (7,2,3), (7,8,6), (6,8,5), (5,8,1), (1,8,4), (4,2,1), (2,4,3), (4,8,7), (7,3,4))
  • IfcCartesianPointList.CoordList: ((0.,0.,0.), (1.,0.,0.), (1.,1.,0.), (0.,1.,0.), (0.,0.,2.), (1.,0.,2.), (1.,1.,2.), (0.,1.,2.))
  • IfcIndexedColourMap.ColourIndex: (1, 1, 2, 2, 3, 3, 1, 1, 1, 1, 1, 1, )
  • IfcColourRgbList.ColourList: ((1.,0.,0.), (0.,1.,0.), (1.,1.,0.))

Figure 542 — Indexed colour map geometry

 

HISTORY  New entity in IFC4.

Attribute definitions
#AttributeTypeCardinalityDescription G
1MappedToIfcTessellatedItem Reference to the IfcTessellatedFaceSet to which it applies the colours and alpha channel. X
2OpacityIfcNormalisedRatioMeasure? The the opacity value, that applies equaly to all faces of the tessellated face set. 1.0 means opaque, and 0.0 completely transparent. If not provided, 1.0 is assumed (all colours are opque).
NOTE  The definition of the alpha channel component for opacity follows the new definitions in image processing, where 0.0 means full transparency and 1.0 (or 2bit depths -1) means fully opaque. This is contrary to the definition of transparency in IfcSurfaceStyleShading.
X
3ColoursIfcColourRgbList Indexable list of lists of quadruples, representing RGB colours. X
4ColourIndexIfcPositiveIntegerL[1:?] Index into the IfcColourRgbList for each face of the IfcTriangulatedFaceSet. The colour is applied uniformly to the indexed face. X
Inherited definitions from supertypes
Entity inheritance IfcPresentationItem
Attribute inheritance
#AttributeTypeCardinalityDescriptionG
IfcPresentationItem
IfcIndexedColourMap
1MappedToIfcTessellatedItem Reference to the IfcTessellatedFaceSet to which it applies the colours and alpha channel. X
2OpacityIfcNormalisedRatioMeasure? The the opacity value, that applies equaly to all faces of the tessellated face set. 1.0 means opaque, and 0.0 completely transparent. If not provided, 1.0 is assumed (all colours are opque).
NOTE  The definition of the alpha channel component for opacity follows the new definitions in image processing, where 0.0 means full transparency and 1.0 (or 2bit depths -1) means fully opaque. This is contrary to the definition of transparency in IfcSurfaceStyleShading.
X
3ColoursIfcColourRgbList Indexable list of lists of quadruples, representing RGB colours. X
4ColourIndexIfcPositiveIntegerL[1:?] Index into the IfcColourRgbList for each face of the IfcTriangulatedFaceSet. The colour is applied uniformly to the indexed face. X
Formal representations
XML Specification
 <xs:element name="IfcIndexedColourMap" type="ifc:IfcIndexedColourMap" substitutionGroup="ifc:IfcPresentationItem" nillable="true"/>
 <xs:complexType name="IfcIndexedColourMap">
  <xs:complexContent>
   <xs:extension base="ifc:IfcPresentationItem">
    <xs:sequence>
     <xs:element name="Colours" type="ifc:IfcColourRgbList" nillable="true"/>
    </xs:sequence>
    <xs:attribute name="Opacity" type="ifc:IfcNormalisedRatioMeasure" use="optional"/>
    <xs:attribute name="ColourIndex" use="optional">
     <xs:simpleType>
      <xs:restriction>
       <xs:simpleType>
        <xs:list itemType="ifc:IfcPositiveInteger"/>
       </xs:simpleType>
      </xs:restriction>
     </xs:simpleType>
    </xs:attribute>
   </xs:extension>
  </xs:complexContent>
 </xs:complexType>
EXPRESS Specification
ENTITY IfcIndexedColourMap
 SUBTYPE OF (IfcPresentationItem);
  MappedTo : IfcTessellatedItem;
  Opacity : OPTIONAL IfcNormalisedRatioMeasure;
  Colours : IfcColourRgbList;
  ColourIndex : LIST [1:?] OF IfcPositiveInteger;
END_ENTITY;

Link to EXPRESS-G diagram EXPRESS-G diagram

References  References: IfcTessellatedItem

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