Wednesday, June 26, 2013

Differences in IES format 1995 and before versus 2001 and later

IES files contain 3 number for luminaire luminous length, width and height. By changing sign or setting to zero more shapes than rectangular can be described. In the standard for IES files for 2001 and later the definitions changed. Below is a comparison.

Differences between 1995 and before and 2001 and later IES files.

width length height IES1995 and before IES2001 and later
0 0 0 point point
+w +l 0 rectangular (implied) rectangular
+w +l +h rectangular (default) rectangular with sides
-d 0 0 circular UNDEFINED
-d -d 0 UNDEFINED circular
-d -d +h UNDEFINED vertical circular cylinder
-d 0 +h vertical circular cylinder UNDEFINED
-w -l 0 UNDEFINED ellipse
-w -l +h UNDEFINED vertical ellipsoid cylinder
-d -d -d UNDEFINED sphere
-w -l -h UNDEFINED ellipsoidal spheroid
-d +l -d UNDEFINED horizontal circular cylinder along photometric horizontal
0 +l -d horizontal circular cylinder along photometric horizontalUNDEFINED
-w +l +h ellipse allong luminaire lengthUNDEFINED
-w +l -h ellipsoid along luminaire length horizontal ellipsoidal cylinder along photometric horizontal
+w 0 -d horizontal circular cylinder perpendicular to photometric horizontal UNDEFINED
+w -d -d UNDEFINED horizontal circular cylinder perpendicular to photometric horizontal
+w -l +h ellipse cylinder along luminaire widthUNDEFINED
+w -l -h ellipsoid along luminaire width horizontal ellipsoidal cylinder perpendicular to photometric horizontal
-d 0 -d sphere vertical circle facing photometric horizontal
-w 0 -h UNDEFINED vertical ellipse facing photometric horizontal