[Radiance-general] Radiance, objline, objpict etc..

[Rob Guglielmetti]

On Jan 25, 2008, at 5:34 PM, steve michel wrote:

>
> Hi Thomas,
>
>
> There is light in the scene but the lighting polygon is black not  
> even lit. As you said I placed the polygons an inch blow the  
> ceiling plane to no effect. It's important that the sources be  
> visible for presentation purposes.

I may have missed this, but what kind of light fixture is it?  If  
it's a low brightness downlight or something similar with good  
shielding, It may just be that your viewing angle to the light source  
is shallow enough that you cannot see any luminance.  Radiance will  
render the disc according to what the ies file says is appropriate  
for that angle.  It does tend to appear "all or nothing", that is, if  
you're looking straight up into the fixture the disc is all white and  
very shallow angles appear all black.  If you want to model the  
appearance of the light fixture itself, you will have to get a little  
fancier and model the geometry, include a glow material for the lamp  
brightness, and enclose the whole thing in an illum sphere and apply  
the luminance distribution to that.  This is well detailed in RwR and  
in various posts on this list.  I have little experience doing this  
without the help of front ends like Rayfront, but several people  
around here are.  For my needs, the default rendering of the light  
sources is generally adequate.

- Rob Guglielmetti
www.rumblestrip.org