"jute" <nomail@nomail> wrote in message
news:web.4159ba8d8cfd44a0b2800eda0@news.povray.org...
> "A.Brinkmann" <arb### [at] gmxde> wrote:
> > I think, with such a low count you won't get any kind of reliable
results,
> > the number of samples is just too low. And I do think (without being an
>
> I ran some tests and while the results remain inconclusive, it seems like
my
> biggest concern is indeed the low sample count.  There's also a noticeable
> difference between the halton sample set and Thies Heidecke's 'sunflower'
> set that I've been using for the last week -- sunflower gives a lot
> brighter (I'd say +0.2 brightness) image with low count.  This is not a
> drawback for the sample set, at least now that I know about it.
>
> However, the +w/+h problem clearly manifests itself only with low counts.
>
> The problem of my testing was that I was somewhat unable to reproduce the
> symptoms with the camera position I used, even as just yesterday I was
> rendering images from the same position and the problem manifested itself
> profoundly.
>
> What I've come to believe now is that I'm simply making so many
simultaneous
> changes to the scene description between renders that I can't really keep
> track of them, and it happens that I've changed something even when I
> believe I haven't.  In other words, I'm willing to rest this case at least
> until I get time to do some *proper* tests and be certain if there really
> is something fishy going on.  Besides, I'm getting rather good at
> pre-guessing good values for brightness & exposure :D
>
> Now, where was that intersection { ...
>
> --
> jussi.kantola
>
>


Not sure if you resolved the problem or not, but when reading through I was
a bit startled by your settings.  In my experience, final scenes rarely can
use less than 150 samples (this is highly dependant on the error_bound).
Also, when doing a test render for, I drop nearest count to 5, but when
testing the radiosity, I move it to at least 15 or it's final setting of 20.
I am very curious about this scene, so far I have never required above a
recursion level of 5.  If time constraints allow, maybe you can try tracing
with a lower recursion level and higher settings?  A typical radiosity block
for me in late stages of radiosity tuning looks like:

#local do_rad = 1;

global_settings{

#if(do_rad)
  radiosity{
    pretrace_start 0.080
    pretrace_end   0.005
    count 200
    nearest_count 20
    error_bound 1    // highly scene dependant!
    recursion_limit 4
    low_error_factor .5
    gray_threshold 0.75
    minimum_reuse 0.0015
    brightness .95
    adc_bailout 0.01/2
    normal on
    //media on
    //save_file "file_name"
    //load_file "file_name"
    always_sample off
    //max_sample 1.0
  }
#end
}


HTH

Reactor

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