注：根据ISO 10303-46的定义：
光源实体由曲面样式渲染中指定的反射率确定。在逐个曲面的基础上应用照明：未定义曲面之间的交互，例如阴影或反射。
注：实体改编自ISO 10303-46中定义的光源。
注：除了ISO10303-46中定义的属性外，还添加了ISO/IEC 14772-1:1997（VRML）中的以下附加属性：模糊度和强度。属性名也已添加（因为它不是通过表示项继承的）。
IFC2x中增加的新实体，在IFC2x2中重命名和增强。
| # | Attribute | Type | Cardinality | Description | C |
|---|---|---|---|---|---|
| IfcRepresentationItem | |||||
| LayerAssignment | IfcPresentationLayerAssignment @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. | X | |
| StyledByItem | IfcStyledItem @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. | X | |
| IfcGeometricRepresentationItem | |||||
| IfcLightSource | |||||
| 1 | Name | IfcLabel | [0:1] | The name given to the light source in presentation. | X |
| 2 | LightColour | IfcColourRgb | [1:1] | 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 |
| 3 | AmbientIntensity | IfcNormalisedRatioMeasure | [0:1] | 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 |
| 4 | Intensity | IfcNormalisedRatioMeasure | [0:1] | 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 |
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;