IfcIndexedColourMap

Item	SPF	XML	Change	Description
IFC2x3 to IFC4 4.0.0.0
IfcIndexedColourMap			ADDED
IFC4 Addendum 1 4.0.1.0
IfcIndexedColourMap
Opacity	X	X	MODIFIED	Name changed from Overrides to Opacity. Type changed from IfcSurfaceStyleShading to IfcNormalisedRatioMeasure.
ColourIndex			MODIFIED	Type changed from INTEGER to IfcPositiveInteger.
IFC4 Addendum 2 4.0.2.0
IfcIndexedColourMap
Opacity		X	MODIFIED	Xsdformat changed from Attribute to Content.
IFC4X3_ADD2 to IFC4X4_draft
IfcIndexedColourMap
MappedTo	X	X	MODIFIED	Type 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.

Figure 541 — Indexed colour map

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

#	Attribute	Type	Cardinality	Description	G
1	MappedTo	IfcTessellatedItem		Reference to the IfcTessellatedFaceSet to which it applies the colours and alpha channel.	X
2	Opacity	IfcNormalisedRatioMeasure	?	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 2^{bit depths} -1) means fully opaque. This is contrary to the definition of transparency in IfcSurfaceStyleShading.	X
3	Colours	IfcColourRgbList		Indexable list of lists of quadruples, representing RGB colours.	X
4	ColourIndex	IfcPositiveInteger	L[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

Attribute inheritance

#	Attribute	Type	Cardinality	Description	G
IfcPresentationItem
IfcIndexedColourMap
1	MappedTo	IfcTessellatedItem		Reference to the IfcTessellatedFaceSet to which it applies the colours and alpha channel.	X
2	Opacity	IfcNormalisedRatioMeasure	?	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 2^{bit depths} -1) means fully opaque. This is contrary to the definition of transparency in IfcSurfaceStyleShading.	X
3	Colours	IfcColourRgbList		Indexable list of lists of quadruples, representing RGB colours.	X
4	ColourIndex	IfcPositiveInteger	L[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;

 EXPRESS-G diagram

	Liste von Indizes für Farbwerte
	Indexed Colour Map