IfcLightSource

Natural language names
Lichtquelle
Light Source
Source de lumière
Semantic definitions at the entity
Entity definition

NOTE  Definition according to ISO 10303-46:
The light source entity is determined by the reflectance specified in the surface style rendering. Lighting is applied on a surface by surface basis: no interactions between surfaces such as shadows or reflections are defined.

NOTE  Entity adapted from light_source defined in ISO 10303-46.

NOTE  In addition to the attributes as defined in ISO10303-46 the following additional properties from ISO/IEC 14772-1:1997 (VRML) are added: ambientIntensity and Intensity. The attribute Name has been added as well (as it is not inherited via representation_item).

HISTORY  New entity in IFC2x, renamed and enhanced in IFC2x2.

Attribute definitions
#AttributeTypeCardinalityDescription G
1NameIfcLabel? The name given to the light source in presentation. X
2LightColourIfcColourRgb Definition from ISO/CD 10303-46:1992: Based on the current lighting model, the colour of the light to be used for shading. Definition from VRML97 - ISO/IEC 14772-1:1997: The color field specifies the spectral color properties of both the direct and ambient light emission as an RGB value. X
3AmbientIntensityIfcNormalisedRatioMeasure? Definition from VRML97 - ISO/IEC 14772-1:1997: The ambientIntensity specifies the intensity of the ambient emission from the light. Light intensity may range from 0.0 (no light emission) to 1.0 (full intensity). X
4IntensityIfcNormalisedRatioMeasure? Definition from VRML97 - ISO/IEC 14772-1:1997: The intensity field specifies the brightness of the direct emission from the ligth. Light intensity may range from 0.0 (no light emission) to 1.0 (full intensity). X
Inherited definitions from supertypes
Entity inheritance IfcLightSourceAmbient IfcLightSourceDirectional IfcLightSourceGoniometric IfcLightSourcePositional IfcGeometricRepresentationItem IfcRepresentationItem
Attribute inheritance
#AttributeTypeCardinalityDescriptionG
IfcRepresentationItem
LayerAssignmentIfcPresentationLayerAssignment
@AssignedItems
S[0:1]Assignment of the representation item to a single or multiple layer(s). The LayerAssignments can override a LayerAssignments of the IfcRepresentation it is used within the list of Items.
IFC2x3 CHANGE  The inverse attribute LayerAssignments has been added.
IFC4 CHANGE  The inverse attribute LayerAssignment has been restricted to max 1. Upward compatibility for file based exchange is guaranteed.
X
StyledByItemIfcStyledItem
@Item
S[0:1]Reference to the IfcStyledItem that provides presentation information to the representation, e.g. a curve style, including colour and thickness to a geometric curve.
IFC2x3 CHANGE  The inverse attribute StyledByItem has been added.
X
IfcGeometricRepresentationItem
IfcLightSource
1NameIfcLabel? The name given to the light source in presentation. X
2LightColourIfcColourRgb Definition from ISO/CD 10303-46:1992: Based on the current lighting model, the colour of the light to be used for shading. Definition from VRML97 - ISO/IEC 14772-1:1997: The color field specifies the spectral color properties of both the direct and ambient light emission as an RGB value. X
3AmbientIntensityIfcNormalisedRatioMeasure? Definition from VRML97 - ISO/IEC 14772-1:1997: The ambientIntensity specifies the intensity of the ambient emission from the light. Light intensity may range from 0.0 (no light emission) to 1.0 (full intensity). X
4IntensityIfcNormalisedRatioMeasure? Definition from VRML97 - ISO/IEC 14772-1:1997: The intensity field specifies the brightness of the direct emission from the ligth. Light intensity may range from 0.0 (no light emission) to 1.0 (full intensity). X
Formal representations
XML Specification
 <xs:element name="IfcLightSource" type="ifc:IfcLightSource" abstract="true" substitutionGroup="ifc:IfcGeometricRepresentationItem" nillable="true"/>
 <xs:complexType name="IfcLightSource" abstract="true">
  <xs:complexContent>
   <xs:extension base="ifc:IfcGeometricRepresentationItem">
    <xs:sequence>
     <xs:element name="LightColour" type="ifc:IfcColourRgb" nillable="true"/>
    </xs:sequence>
    <xs:attribute name="Name" type="ifc:IfcLabel" use="optional"/>
    <xs:attribute name="AmbientIntensity" type="ifc:IfcNormalisedRatioMeasure" use="optional"/>
    <xs:attribute name="Intensity" type="ifc:IfcNormalisedRatioMeasure" use="optional"/>
   </xs:extension>
  </xs:complexContent>
 </xs:complexType>
EXPRESS Specification
ENTITY IfcLightSource
 ABSTRACT SUPERTYPE OF(ONEOF(IfcLightSourceAmbient, IfcLightSourceDirectional, IfcLightSourceGoniometric, IfcLightSourcePositional))
 SUBTYPE OF (IfcGeometricRepresentationItem);
  Name : OPTIONAL IfcLabel;
  LightColour : IfcColourRgb;
  AmbientIntensity : OPTIONAL IfcNormalisedRatioMeasure;
  Intensity : OPTIONAL IfcNormalisedRatioMeasure;
END_ENTITY;

Link to EXPRESS-G diagram EXPRESS-G diagram

Link to this page  Link to this page