In article <3a21f759@news.povray.org>, "Andy Cocker" 
<big### [at] mariner9fsnetcouk> wrote:

> When I added the spheres, render time went up from around 5 mins, to 
> over 8 hours! I've no idea why the huge difference... any ideas? The 
> spheres are just a simple union of nested #while..#end loops.

Well, it takes a lot more computational work to check against hundreds 
of spheres than to check against a couple boxes or planes. You might be 
able to help with this by using a nested bounding structure, you know 
what a quad-tree is? Basically, divide each wall of spheres into four 
unions, bounded individually. Divide those unions further into four 
each, bounded individually...etc. This will allow POV to skip testing 
the bounding boxes for most of the spheres. You will have to tell POV 
not to ignore your bounding, though, and you probably won't be able to 
use while loops to generate the walls, though they would be easy to do 
with a recursive macro.

-- 
Christopher James Huff
Personal: chr### [at] maccom, http://homepage.mac.com/chrishuff/
TAG: chr### [at] tagpovrayorg, http://tag.povray.org/

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