"Andrew Wilcox" <awi### [at] unpuzzledcom> wrote in
news:3ff5a0d6@news.povray.org: 

>> Some of the columns of marbles appear to vibrate: they seem to go up
>> and down slightly, even before anything hits them.
> 
> It's probably because the step size is too big, and this particular
> non-common setup of the spheres.   All the spheres in the column fall
> in gravity in one step, but do not interact to correct the fall until
> the next step.  So they fall, correct, fall, correct, thus vibrate. 
> Plus the problem is probably magnified since we have several spheres
> stacked one on top of the other all adding to the end result.

Quite right Andrew.  The sim. step size I used was not much higher than the 
frame step.  If I recall correctly, frames were 120 per second, sim steps 
were 1/200 seconds apart.  I should have at least doubled the sim steps.

Post a reply to this message