IfcLightSourceDirectional

Definition from ISO/CD 10303-46:1992: The light source directional is a subtype of light source. This entity has a light source direction. With a conceptual origin at infinity, all the rays of the light are parallel to this direction. This kind of light source lights a surface based on the surface's orientation, but not position.

Definition from ISO/IEC 14772-1:1997: The directional light node defines a directional light source that illuminates along rays parallel to a given 3-dimensional vector. Directional light nodes do not attenuate with distance. Directional light nodes are specified in the local coordinate system and are affected by ancestor transformations.

> NOTE: Corresponding STEP entity: light_source_directional. Please refer to ISO/IS 10303-46:1994, p. 32 for the final definition of the formal standard.

> NOTE: In addition to the attributes as defined in ISO10303-46 the additional property from ISO/IEC 14772-1:1997 (VRML) AmbientIntensity and Intensity are inherited from the supertype.

> HISTORY: This is a new entity in IFC 2x, renamed and enhanced in IFC2x2.

EXPRESS specification:

ENTITY IfcLightSourceDirectional
SUBTYPE OF ( | IfcLightSource);
Orientation | : | IfcDirection;
END_ENTITY;

Attribute definitions:

Orientation | : | Definition from ISO/CD 10303-46:1992: This direction is the direction of the light source. Definition from VRML97 - ISO/IEC 14772-1:1997: The direction field specifies the direction vector of the illumination emanating from the light source in the local coordinate system. Light is emitted along parallel rays from an infinite distance away.

Inheritance graph

ENTITY IfcLightSourceDirectional;
ENTITY IfcRepresentationItem;
INVERSE
LayerAssignments | : | SET OF IfcPresentationLayerAssignment FOR AssignedItems;
StyledByItem | : | SET [0:1] OF IfcStyledItem FOR Item;
ENTITY IfcGeometricRepresentationItem;
ENTITY IfcLightSource;
Name | : | OPTIONAL IfcLabel;
LightColour | : | IfcColourRgb;
AmbientIntensity | : | OPTIONAL IfcNormalisedRatioMeasure;
Intensity | : | OPTIONAL IfcNormalisedRatioMeasure;
ENTITY IfcLightSourceDirectional;
Orientation | : | IfcDirection;
END_ENTITY;