[Radiance-general] -ar and large scenes

[Rob Guglielmetti]

Howdy folks.

Been playing with the new "drape" command in AutoCAD 2006.  This command 
makes it extremely easy to create terrain meshes, and I'm working on a 
project that is located in a valley so I thought it'd be nice to be able 
to model the valley since the mountains provide some considerable 
shading in the morning and afternoons.  But of course now my octree 
bounding box is quite large, which leads me to this ditty from the 
rtrace manpage, regarding the -ar parameter:

*"*The maximum  ambient  value  density  is the scene size times the ambient accuracy 
(see the /-aa/ option below)  divided  by  the ambient  resolution."

By having such an expansive outdoor geometry, am I forcing a very high 
-ar in order to get good data from rtraces in an interior space, or if I 
use enough -ab will this not matter?  A test render looked very flat 
too; I thought it was the mellow settings I used for the test render, 
but now I'm concerned that without -ar's in the thousands (!), my 
renderings will always look very flat. 

- Rob Guglielmetti
www.rumblestrip.org