On 2-9-2017 6:31, omniverse wrote:
> Alain <kua### [at] videotronca> wrote:
>> Le 17-08-31 à 18:58, Loren a écrit :
>>>          media{ emission Red intervals 30 samples 100,100 }
>> Yuck! That WAS ok in version 3.5 and older that used sampling method 2
>> as the default. As of version 3.6, the sampling method is method 3 and
>> it must use intervals 1 (the default value).
>> Using method 3, more intervals only dramatically slow you down. It can
>> also cause some artefacts.
>> Also :
>> 1) It only use a single value for samples. If a second value is used,
>> it's silently ignored.
>> 2) confidance and variance are also silently ignored as they are
>> meaningless when you have only a single interval.
>>
>> Defaults for media in version 3.6+
>> method 3
>> samples 10
>> confidance Not Applicable
>> variance N/A
>> intervals 1
>> jitter 1
>>
>> Alain
> 
> Well I'm learning something, again, because I had thought
> 
>   samples LesserInteger, GreaterInteger
> 
> was valid for method 3. And I also thought samples 1,1 was the default.
> Reading the 3.7 doc I don't find it saying the above you tell of, not that I
> don't believe you Alain, but I refer to the docs a lot and try to believe what I
> read there. :)
> 

Alain is absolutely right. He is the one person warning us, again and 
again, for the method/intervals/samples misconception cropping up 
regularly in these ng's. Hail to the chief! ;-)

As for the docs, samples LesserInteger, GreaterInteger, is only valid 
for method 1 and 2. I agree that there is an ambiguity where method 3 is 
concerned: paragraph 2.7.2.3 Sampling Parameters & Methods in the wiki ( 
http://wiki.povray.org/content/Reference:Sampling_Parameters_%26_Methods 
) does not state clearly that the second term is ignored when using 
method 3. This should be changed.


-- 
Thomas

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