IfcIndexedColourMap

BACnet MVD

#### IfcIndexedColourMap

Natural language names

| Liste von Indizes für Farbwerte
| Indexed Colour Map

Change log

Item | SPF | XML | Change | Description
--- | --- | --- | --- | ---
IFC2x3 to IFC4
IfcIndexedColourMap |  |  | ADDED |
IFC4 Addendum 1
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
IfcIndexedColourMap |  |  |  |
Opacity |  | X | MODIFIED | Xsdformat changed from Attribute to Content.

##### 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 339 shows the use of IfcTriangulatedFaceSet with colours per face.

Figure 339 — Indexed colour map

Figure 340 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 340 — Indexed colour map geometry |

> HISTORY New entity in IFC4.

Attribute definitions

# | Attribute | Type | Cardinality | Description | B
--- | --- | --- | --- | --- | ---
1 | MappedTo | IfcTessellatedFaceSet |  | Reference to the IfcTessellatedFaceSet to which it applies the colours and alpha channel. | X | 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 2bit depths -1) means fully opaque. This is contrary to the definition of transparency in IfcSurfaceStyleShading.

X

X

3 | Colours | IfcColourRgbList |  | Indexable list of lists of quadruples, representing RGB colours. | X | 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 | X

##### Inherited definitions from supertypes

Entity inheritance
Attribute inheritance

# | Attribute | Type | Cardinality | Description | B
--- | --- | --- | --- | --- | ---
IfcPresentationItem
IfcIndexedColourMap
1 | MappedTo | IfcTessellatedFaceSet |  | Reference to the IfcTessellatedFaceSet to which it applies the colours and alpha channel. | X | 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 2bit depths -1) means fully opaque. This is contrary to the definition of transparency in IfcSurfaceStyleShading.

X

X

3 | Colours | IfcColourRgbList |  | Indexable list of lists of quadruples, representing RGB colours. | X | 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 | 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 : IfcTessellatedFaceSet;
Opacity : OPTIONAL IfcNormalisedRatioMeasure;
Colours : IfcColourRgbList;
ColourIndex : LIST [1:?] OF IfcPositiveInteger;
END_ENTITY;

EXPRESS-G diagram

`

References: IfcTessellatedFaceSet

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