[Radiance-general] physically-based landscapes

[Carsten Bauer]

Hi Rob,

is there snow on the mountain top? Can you go skiing over there?

Excluding objects form the ambient calculation is done by setting the -ae 
parameter to the objects material name (-ae mat_name or -aE 
file_with_matnames). So excluding the mountains is no problem, the drawback 
is, that Radiance determines the resolution of its ambient cache (-ar 
setting) dependent on the scene bounding cube. So a HUUUGE bounding cube 
results in values spaced so far apart that probably only one falls into your 
room. (Unless you set up -ar extremely high, if everything outside is 
excluded, this might even work ...)

But why not tread an intermediate path: set up a 3D landscape model and render 
some pictures with it from your viewing point.  They contain the exact 
radiance values, so in a second step you can map them with colorpict to a 
plane made of  glow with fourth param set to zero, and put this plane 100 or 
200 m apart from your scene. This will keep the blowing up of the scene 
reasonable and still deliver correct results. Do some checking if the 
settings are right, i.e compare the landsscape rendering with your fake 
landscape rendering, one never knows ...)

-cb