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root/radiance/ray/src/cal/cal/trans2.cal
Revision: 1.1
Committed: Sat Feb 22 02:07:21 2003 UTC (21 years, 2 months ago) by greg
Branch: MAIN
CVS Tags: rad5R2, rad4R2P2, rad5R0, rad5R1, rad3R7P2, rad3R7P1, rad4R2, rad4R1, rad4R0, rad3R5, rad3R6, rad3R6P1, rad3R8, rad3R9, rad4R2P1
Log Message:
Changes and check-in for 3.5 release
Includes new source files and modifications not recorded for many years
See ray/doc/notes/ReleaseNotes for notes between 3.1 and 3.5 release

File Contents

# User Rev Content
1 greg 1.1 {
2     These formulas compute the index of refraction and
3     normal transmission for a pane of glass given the
4     measured normal transmittance and reflectance values,
5     Tn and Rn, respectively.
6    
7     These formulas are approximate -- the exact solution
8     involves a quartic equation and seemed more trouble
9     than it was worth. If you know the index of refraction,
10     you are better off with the formula in trans.cal.
11    
12     Oct. 2002 Greg Ward
13     }
14     { formula for normal transmission }
15     tn = Tn / (1 - Rn);
16     F = Rn / (1 + tn*tn);
17     n = (1 + sqrt(F)) / (1 - sqrt(F));