IfcIndexedColourMap

Natural language names
deListe von Indizes für Farbwerte
enIndexed Colour Map
Change log
ItemSPFXMLChangeDescription
IFC2x3 to IFC4
    IfcIndexedColourMapADDED
IFC4 Addendum 1
    IfcIndexedColourMap
      OpacityXXMODIFIEDName changed from Overrides to Opacity.
Type changed from IfcSurfaceStyleShading to IfcNormalisedRatioMeasure.
      ColourIndexMODIFIEDType changed from INTEGER to IfcPositiveInteger.
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 363 shows the use of IfcTriangulatedFaceSet with colours per face.

IfcIndexedColourMap_01

Figure 363 — Indexed colour map

 

IfcIndexedColourMap_example-01

 

Figure 364 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 364 — Indexed colour map geometry

 
HISTORY  New entity in IFC4.
Attribute definitions
#AttributeTypeCardinalityDescription C
1MappedToIfcTessellatedFaceSet[1:1] Reference to the IfcTessellatedFaceSet to which it applies the colours and alpha channel.X
2OpacityIfcNormalisedRatioMeasure[0:1] 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[1:1] 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
#AttributeTypeCardinalityDescriptionC
IfcPresentationItem
IfcIndexedColourMap
1MappedToIfcTessellatedFaceSet[1:1] Reference to the IfcTessellatedFaceSet to which it applies the colours and alpha channel.X
2OpacityIfcNormalisedRatioMeasure[0:1] 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[1:1] 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
Examples
Formal representations
XSD 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 : IfcTessellatedFaceSet;
  Opacity : OPTIONAL IfcNormalisedRatioMeasure;
  Colours : IfcColourRgbList;
  ColourIndex : LIST [1:?] OF IfcPositiveInteger;
END_ENTITY;

Link to EXPRESS-G diagram EXPRESS-G diagram

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