IfcLightDistributionDataSourceSelect

Definition from IAI: A goniometric light gets its intensity distribution function (how much light goes in any one direction) from one of two sources: (i) an industry-standard file, (ii) from distribution data passed directly via the IfcLightIntensityDistribution.

The light distribution provides the luminous intensity distribution according to some standardized light distribution curves.

Select:

Type | Definition
IfcExternalReference | Light distribution is represented by a standard photometric data file such as Eulumdat, IES, CIBSE TM14.
IfcLightIntensityDistribution | For representing a light distribution directly the following values needs to be given in a table like structure with column and row headings. These headings should contain the angles (C/γ or B/β ) and the table body contains the intensity values, (normally normalized to cd/Klm). The angles can be non- equidistant and the angle steps can be almost any value in the valid range, so a list of all available angles in both directions covers all cases.

> HISTORY New type in IFC Release 2x Edition 2.

EXPRESS specification:

TYPE IfcLightDistributionDataSourceSelect = SELECT
( | IfcExternalReference, IfcLightIntensityDistribution);
END_TYPE;