IfcLightSource

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;