From: Josh Vermaas (
Date: Fri Jun 27 2014 - 10:52:24 CDT

Theoretically its something like 1/x. More precisely a new animation
frame is drawn once the time since the last frame exceeds (1-n) * 0.5
seconds (at least that's how I read Animation.C). In practice this you
won't get 1/x performance, since it takes a finite amount of time to
render a frame. You notice this most acutely if the systems you work
with vary a great deal in size. A simulation of 2 water molecules
renders very quickly, so you can blaze through lots of frames very
quickly. A multimillion atom simulation renders much more slowly, and
the animation speed then makes absolutely no difference.
-Josh Vermaas

On 6/27/14, 5:38 AM, Samuele Salis wrote:
> Hallo everyone!
> I wonder which analytical function (if someone exists) is used in the
> animate speed n function in text command.
> I know the argument n of the function is a real between 0 and 1 and it
> grows roughly exponentially as a function of n.
> I was trying to fit the curve, but I didn't find the right analytical
> function.
> Does someone know the analytical function used in vmd to change the
> speed using animate speed n?
> Thanks,
> Samuele