		Enclosing IES File Notes
		RCSid "$Id: iesnotes.txt,v 1.2 2003/02/28 20:19:26 greg Exp $"

The following notes describe how MGF data is to be referred to by
an enclosing IES luminaire file, and these notes are in a state of flux.

The basic method for specifying an MGF geometry file within an IES
file is a single line immediately preceeding the TILT= line, which reads:

GEOM=file.mgf

where "file.mgf" is replaced by the name of the relevant MGF file.

IES data file contains simplified geometry, which must completely
enclose the detailed geometry specified by the "GEOM=file.mgf" line.
This detailed geometry file is always in meters, whatever the units of
the enclosing IES file, and must have its origin at the center of the
simplified geometry.  The X-axis corresponds to the 0-180 degree plane,
the Y-axis corresponds to the 90-270 degree plane, and the Z-axis
corresponds to the up direction.  (This is a right-handed coordinate
system.)

The emission values in the MGF file will be multiplied by the usual
IES luminaire factors, i.e. the tilt factors (if any), the candela
multiplier, the ballast factor and the ballast lamp factor.  Thus,
the MGF file emissions should correspond to those of the as-tested
luminaire configuration.
