A few observations and questions:

Firstly: at least to me, the jitter value seems to have a disproportionately
strong effect. If I use more jitter than around 0.03 in my spray (quite fast
flow at a tight angle), the particles go all over the place. I understand that
increased speed > greater movement per iteration > greater jitter influence, but
in my case (the "Absudity" scene) the flow speed is 1.2 - not outrageously fast
IMO. Just a minor problem, but still I wonder...

Also, I tried both a little animation and motion blurring the particles. In both
cases the system seems too erratic to give the illusion of 'flow', particles
jump around and *seem* to disappear at a random age?! Might be some
misunderstanding on my part, but it's a relatively simple system with narrow
angle, long lifespan and very low jitter. The animations were 4 frames per TU,
so it shouldn't look all that choppy. I am not wrong in assuming that animation
is done simply through the 'time' parameter, am I?

About the 'lifespan' value: is it measured in time units or iterations? The
former would be more correct IMO, since increasing simulation accuracy should
not affect the number of particles. And even if I set 'lifespan' much larger
than both time and iterations, I still get the "n particles destroyed" message
after a simulation. What does that mean? And, could you add output of the number
of particles in the scene?

Finally, 'cause I'm just too lazy to test <g>: how are the particles arranged
for the get_particle index, newest to oldest or vice versa? I would like to have
the same index number always assigned to the same particle, at any point in
time, but with all the creation and destruction this seems iffy.

-- 
Margus Ramst

Personal e-mail: mar### [at] peakeduee
TAG (Team Assistance Group) e-mail: mar### [at] tagpovrayorg

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