[Radiance-general] Infrared scene simulation

[Alexander Utz]

Hi Greg,

after I put some more unsuccessfull effort in trying to find an alternative
to Radiance for my infrared-simulation problem I decided to try it with Radiance
and see what comes out. So I hope you don't mind if I bother you with some
stupid questions again.

I calculated the total amount of energy emitted by a 300°K blackbody as 
146.305W/(sr m^2). So the material for my source becones

     void light bright
     0
     0
     3  48.77 48.77 48.77

right? Now my Problem is how to create a material mixed from a glow and a 
reflective material. I must admit I am not able to figure out how to do this
from the available documentation. I tried the following

     void plastic brown
     0
     0
     5  .2  .1  .1  0  0

     brown glow brown_glow
     0
     0
     4 100 100 100 100

     brown_glow sphere BB
     0
     0
     4  2  1  1.5  .125

just as a test. oconv runs over it without complaints - but when I wan't to
watch the scene using rvu it says: 
	rvu: fatal - conflicting material "lbrown" for sphere "BB"

By the way what exactly does the maxrad parameter for the glow stand for (I
don't understand what is meant by shadow testing in this context)? Is it the
maximum distance from the glow which will be illuminated by it's radiation?

I also checked the documentation on mixtures but again do not know how I could
use these to solve my problem.

So it would be really great if you could help me out or tell me how others
solved this as you said!

Thanks and Best Regards

Alex

---------------------------------------------------------------------

Sorry, Alex -- it's not really my area of expertise.

Anyone else care to suggest something?

-Greg

> From: Alexander Utz <AlexanderUtz at web.de>
> Date: May 29, 2009 10:36:58 AM PDT
>
> Hi Greg,
>
> first of all thank you for your answer.
>
> I'm aware that modelling infrared radiation as a visible color  
> doesn't make sense in that way. I just wasn't able do figure out  
> how to create a source with the corresponding energy. In my  
> application there would be on esource - a blackbody - at several  
> degrees above roomtemperatur. I want to know the amount of energy  
> which arrives at a certain area within the scene also regarding the  
> energy emerging from other object in "sight" of the detector area.
>
> I thought it might be possible to model the surfaces of these other  
> objects as radiation sources as well, according to their  
> temperature (which will be about 20°C) and emessivities/ 
> reflectances in the far infrared. When searching for a solution I  
> appeared to me that radiance was the most promissing tool - but if  
> you say it's not possible I fear I will have to search on.
>
> Maybe you know a better alternative?
>
> Thanks,
> Alex


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