[Radiance-general] Re: Trees... and defining them in radiance (Lars O. Grobe)

[Georg Mischler]

Greg Ward wrote:

> Hi Lars,
>
> To define trees in Radiance, you can either use an impostor as you do in
> your CAD system, and apply a "colorpict" to it, or (as I prefer), model
> the tree as detailed geometry and compile into an octree for the
> "instance" primitive.  This is very efficient, since a single tree model
> may be duplicated throughout your scene without adding to associated
> scene memory.  You cannot easily get holes in a tree otherwise, as you
> would have to use the "mixdata" type with "void" as one of the
> modifiers, and translate your texture into a large, ASCII data file.

There is a "mixpict" modifier available at least in 3R1p20 and in
the Windows binaries included with Rayfront (but not in those
from Desktop Radiance). This would eliminate the need to
translate anything into ASCII data, you just need to create a
mask picture.  Of course, all the other things said so far remain
true anyway.

The best advice is probably to exclude the tree geometry from the
ambient calculation as mentioned in another reply. Unfortunately
this is not yet directly supported by the Rayfront interface
(which Lars is using), but you can still add the necessary
parameters to the rif file manually. Rayfront will preserve those
entries when reading the file, and correctly pass them to rpict
and friends, even if it doesn't expose them in the GUI.


-schorsch

-- 
Georg Mischler  --  simulations developer  --  schorsch at schorsch.com
+schorsch.com+  --  lighting design tools  --  http://www.schorsch.com/