"Slime" <fak### [at] emailaddress> wrote in message 
news:42debf1e$1@news.povray.org...
>>   4, 4 // number of sources for each axis (above). integers only
>
> So low! I generally use 17, 17 myself. Maybe I could go lower if I used
> jitter more often, but I still recommend using higher numbers than 4; the
> jittering with such a low number probably forces otherwise unnecessary
> anti-aliasing.

To be honest, I actually wrote 5,5 at first and replaced it with 4,4 
thinking it might seem too slow. I subconsciously consider shorter render 
times to be better than quality of the output. A habit formed during the 
days of one-line-at-a-time renderings and hardly ever doing "final" images 
left running for hours or days.

> Of course, with such high numbers it's very important to use adaptive (so
> that you don't actually shoot a full 17x17=289 shadow rays); adaptive 1 
> has
> always worked best for me.

Makes sense. Proves you *can* teach an old dog new tricks. I've always 
stayed away from the larger arrays just because I worried about longer 
render times.

> Finally, I also recommend using a number which is one greater than a power
> of 2 (3, 5, 9, 17, 33) because these make the most sense with the adaptive
> process (See the second picture at
> http://www.povray.org/documentation/view/3.6.1/313/ , which demonstrates 
> why
> this makes sense).

I went looking for the example files and read each lights\arealight*.pov, as 
well as rendering them in a few different ways to check against my usual way 
and what you said. Firstly, I hadn't realized those had 17 by 17 arrays. 
Secondly, I'm amazed to find out that circular.pov has only 4 by 4 arrays 
and the shadows are awful. But even more amazing is that after changing them 
to 9 by 9 the render time only increased from 11.56 to 11.64 seconds! The 
shadows look great, too; although, any higher than 5 by 5 array and the idea 
behind the example of a circular arealight compared to non-circular gets 
lost. ;-)

Apparently I'm going to need to change my mind about arealights and start 
giving better advice about them in the future.

Thankyou for jostling my old POVing into new territory! If I can just train 
myself not to drop back to 4X4's again I should be okay.

Bob

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