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root/radiance/ray/src/cal/cal/blackbody.cal
Revision: 1.1
Committed: Sat Feb 22 02:07:21 2003 UTC (21 years, 1 month ago) by greg
Branch: MAIN
CVS Tags: rad3R5, rad3R6, rad3R6P1
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

# Content
1 {
2 Plank's formula for black body radiation spectrum
3 }
4
5 { Required constants }
6
7 k : 8.617e-5; { Boltzmann constant (eV/K) }
8 h : 4.136e-15; { Plank constant (eV-sec) }
9 e : 1.602e-19; { elemetary charge (Coulombs) }
10 c : 2.998e8; { speed of light (m/sec) }
11
12 {
13 The following distribution is in units of Joules/meter^4,
14 i.e., energy per radiating volume per wavelength
15 lmb (lambda) is expected in nm (10^-9 meter)
16 and T must be given in degrees Kelvin
17 }
18
19 u(lmd,T) : 8*PI*h*e*c*(lmd*1e-9)^-5 / (exp(h*c/(lmd*1e-9*k*T)) - 1);