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greg |
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{ RCSid $Id$ } |
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{ |
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The following calculation uses the BRTDfunc type to reproduce the |
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calculation used by LBL's Optics 5 program for the transmittance |
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and reflectance of coated glazings. This calculation is based |
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on fits for the angular dependence for clear and bronze-coated |
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glazing, and is not terribly accurate. The variables ??_clear |
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below should be replaced by ??_bronze in the case of the bronze |
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glazing model. Used with optics2rad script. |
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5/18/2006 Greg Ward |
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Arguments used for this material should look like: |
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mod BRTDfunc my_glazing |
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10 rR_clear rG_clear rB_clear |
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RTAU*tR_clear GTAU*tG_clear BTAU*tB_clear |
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0 0 0 |
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window.cal |
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0 |
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15 0 0 0 |
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0 0 0 |
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0 0 0 |
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FRRHO FGRHO FBRHO |
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BRRHO BGRHO BBRHO |
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where: |
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FRRHO FGRHO FBRHO is front normal spectral reflectance |
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BRRHO BGRHO BBRHO is back normal spectral reflectance |
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RTAU GTAU BTAU is normal spectral transmittance |
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} |
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{ get normal reflectance } |
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rbase = if(Rdot,10,13); { different front and back } |
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Rred = arg(rbase)*CrP; |
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Rgrn = arg(rbase+1)*CgP; |
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Rblu = arg(rbase+2)*CbP; |
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{ transmittance coefficients } |
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Tclear = clip(-.0015 + RdotP*(3.355 + RdotP*(-3.840 + |
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RdotP*(1.460 + RdotP*.0288)))); |
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Tbronze = clip(-.002 + RdotP*(2.813 + RdotP*(-2.341 + |
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RdotP*(-.05725 + RdotP*.599)))); |
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{ reflectance coefficients } |
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Rclear = clip(.999 + RdotP*(-.563 + RdotP*(2.043 + |
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RdotP*(-2.532 + RdotP*1.054))) - Tclear); |
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Rbronze = clip(.997 + RdotP*(-1.868 + RdotP*(6.513 + |
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RdotP*(-7.862 + RdotP*3.225))) - Tbronze); |
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{ returned spectral transmittance } |
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tR_clear = CrP*Tclear; |
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tG_clear = CgP*Tclear; |
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tB_clear = CbP*Tclear; |
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tR_bronze = CrP*Tbronze; |
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tG_bronze = CgP*Tbronze; |
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tB_bronze = CbP*Tbronze; |
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{ returned spectral reflectance } |
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rR_clear = Rred*(1 - Rclear) + Rclear; |
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rG_clear = Rgrn*(1 - Rclear) + Rclear; |
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rB_clear = Rblu*(1 - Rclear) + Rclear; |
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rR_bronze = Rred*(1 - Rbronze) + Rbronze; |
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rG_bronze = Rgrn*(1 - Rbronze) + Rbronze; |
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rB_bronze = Rblu*(1 - Rbronze) + Rbronze; |
