"Phoenex" <rib### [at] sapopt> wrote:
> After all not always a PRNG implemented on different machines gives the same
> results.
> Is this not also a form of randomness?

It's an absolute No-Go for a RNG to be used for POV-Ray's rand() function.

For instance, one of my current WIPs features some spheres with randomly
oriented grooves, which I let POV-Ray re-calculate every time; in these
grooves, I let POV-Ray scatter other tiny objects, which I let POV-Ray generate
as an #include file on-the-fly only when I deem it necessary, and just #include
the file as generated by a previous run instead.

For this to work, I absolutely need the RNG sequences to be reproducible from
run to run.

But not only that - I also need the sequences to be reproducible regardless of
the computer system POV-Ray runs on, because I usually design and quick-preview
my scenes on a 32-bit Windows XP machine, but do the more time-consuming test
renders and final renders on a 64-bit Linux machine. And to save time, I
positively want to avoid having to re-calculate the #include files. Let alone
that I may also want to try several RNG seeds to see which produces the nicest
orientation of grooves - and in that case I positively want the Linux machine
to produce exactly the same orientation as the Windows machine.

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