"Greg M. Johnson" <pte### [at] thecommononethatstartswithYcom> wrote in 
message news:46f0778a@news.povray.org...
> Warp wrote:
>
>> John VanSickle <evi### [at] hotmailcom> wrote:
>>> #declare rsA=seed(Frame);
>>> #declare rsB=seed(floor(12345*rand(rsA)));
>>
>>> And use rsB as the primary seed for things.
>>
>>   Knowing how the random number generator used by povray works (it's
>>   pretty
>> simple, actually), I'm quite convinced that method doesn't actually add
>> any more "randomness" than simply using rsA as the seed. It simply
>> produces different results, that's all.
>>
>
> If the phenomenon I observed is valid, then it could be helpful to have an
> less-predictable value by setting the seed based on something that varies
> wildly as a function of frame_number: I was using cos & sin.

I would probably guess that you don't necessarily need increased randomness 
(or unpredicitability), just that the mode and value-step in the frame/seed 
sequence does shift to a harder pattern for the eye/brain to see.  Which 
John's trick might do without actually increasing "randomness".  In the 
absence of knowledge of the algorithm, experiment.  :-)

Brian

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