IfcIndexedColourMap

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 275 shows the use of IfcTriangulatedFaceSet with colours per face.


Figure 275 — Indexed colour map

Figure 276 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 276 — Indexed colour map geometry

HISTORY New entity in IFC4.

Attribute definitions

#	Attribute	Type	Cardinality	Description	B
1	MappedTo	IfcTessellatedFaceSet	[1:1]	Reference to the IfcTessellatedFaceSet to which it applies the colours and alpha channel.	X
2	Opacity	-		This attribute is out of scope for this model view definition and shall not be set.
3	Colours	IfcColourRgbList	[1:1]	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	B
IfcPresentationItem
IfcIndexedColourMap
1	MappedTo	IfcTessellatedFaceSet	[1:1]	Reference to the IfcTessellatedFaceSet to which it applies the colours and alpha channel.	X
2	Opacity	-		This attribute is out of scope for this model view definition and shall not be set.
3	Colours	IfcColourRgbList	[1:1]	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

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="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 IfcStrippedOptional;

  Colours : IfcColourRgbList;

  ColourIndex : LIST [1:?] OF IfcPositiveInteger;

END_ENTITY;

 EXPRESS-G diagram

Item	Change	Description
IFC2x3 to IFC4
IfcIndexedColourMap	ADDED
IFC4 to IFC4 ADD1
IfcIndexedColourMap
ColourIndex	MODIFIED	Type changed from INTEGER to IfcPositiveInteger.

	Liste von Indizes für Farbwerte
	Indexed Colour Map