> when i create an animation with particles, will the particle always show
> exactly the same behaviour when i render the animation two times? or are
> there random elements in the algorithm which change the output?
"random" is a strange thing in computers, because they are so
predictable. Random number generators usually spit out exactly the same
string of numbers if they are started the same way, so they use a 'seed'
number to kick them off. If this 'seed' is generated internally it is
often taken from some part of the system that changes rapidly, like the
number of cpu cycles since boot up.
with particles you cant specify a seed, so you rely on the internal
algorithms. I have found that two lights with the same parameters on
them will generate exacly the same set of particles. To give the
appearance of randomness you use things like turbulance and slight
varying of the generation parameters (though i would have liked the
ability to seed each particle emitter my self).