[ODE] Increasing number of particales changes physics

Jacob Ole Juul Kolding dacobi at gmail.com
Sat Aug 12 10:36:17 MST 2006


OK I have a fixed step time and that works fine.

The next problem is when I enable collision (So that the particles bounce
against a floor). When the simulation has up to 350 particles it seem to run
smoothly and stable, but above 350 it will eventually suffer a slowdown
death causing the app to be unresponsive.

I switched to HashSpace and set the category/collide bits so that the
particles should not collide with each other but only the floor.

Is this a bottleneck?

/Jacob Kolding


On 8/11/06, Jon Watte <hplus at mindcontrol.org> wrote:
>
> Correct. You need to use a fixed time step. Such as in
> http://www.mindcontrol.org/~hplus/graphics/game_loop.html<http://www.mindcontrol.org/%7Ehplus/graphics/game_loop.html>
>
> Jacob Ole Juul Kolding wrote:
> > I'm implementing a particle system in ODE and have encountered the
> > problem that when the number of particles increase the physics change
> > in the the way the even though the same force is applied, the more
> > particles are in the simulation the longer they will travel.
> >
> > My guess is that since i step the world each frame, when the frame
> > rate drops the step time increase which changes the outcome of the
> > simulation?
> >
> > Anyone have an idea how to help this problem?
> >
> > /Jacob Kolding
> > ------------------------------------------------------------------------
> >
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