[Radiance-general] Illuminance falsecolor pictures

[Lars O. Grobe]

> rpict -i -vf default.vp -x 512 -y 512 kontor.oct > irrad.pic
> rpict -vf default.vp -x 512 -y 512 kontor.oct > rad.pic
> falsecolor -i irrad.pic -p rad.pic -cl -n 10 -l cd/m2 > lum.pic
> 
> I am not sure that these inputs are correct because I get  a high 
> contrast in the picture (black room with a white window). Therefore it 
> is hard the separate the objects and tell the different luminances in 
> the picture.

Start to solve that problem step by step. It seams that the picture 
which you want to use as a background for the isolines is not what you 
expected it to be. You should have that annoying high contrast picture 
if you just look at rad.pic : ximage rad.pic

Usually, the output of rpict is filtered before being viewed. Read the 
manpage of pfilt and maybe pcond. Here you could e.g. adjust the 
"exposure", whih defines how the values of your rendering will be mapped 
to the values that your screen can actually display.

Another problem in your case might be that in your scene, the default of 
one ambient bounce will most probably not enough to model the reflected 
indirected light. Did you use a ground plan for your building (you 
mentioned surroundings)? You should try to render with -ab 2 or -ab 3, 
as light reflected from the surrounding surfaces to the ceiling and 
walls, and from there to floor, ceiling, walls, may have a big influence 
of the result.

Forget about falsecolor until you got the previous steps in the process 
running. First you need the background image, before you solved that you 
do not need to worry how to combine it with contour lines. BUT also for 
irrad.pic, you should definitely increase the ambient parameters for the 
scene as you described it.

Good luck, Lars.