[ODE] reverse timestep?

[George Birbilis]

better record the world state instead (positions, maybe velocities and
accelerations too if you need to display them, joint values etc.) and be
able to play it back

e.g. 3impact (uses ODE internally)  supports such recording of the action
for later playback (apart from saving screenshot/movie). I suppose you could
somehow make that recording play backwards (or can suggest it to its author
as an addition [have a "rate" floating point parameter that is, 0 for
paused, 1 for normal fwd speed, -1 for normal reverse speed, 2 for double
fwd speed, -2 for double reverse speed etc.)

-----
George Birbilis (birbilis at kagi.com)
http://www.kagi.com/birbilis
--------------
----- Original Message ----- 
From: "Jon Watte" <hplus-ode at mindcontrol.org>
To: "Tyler Streeter" <tylerstreeter at yahoo.com>; <ode at q12.org>
Sent: Monday, May 03, 2004 6:51 PM
Subject: RE: [ODE] reverse timestep?


>
> I don't think this is generally possible. When a body collides with more
than one other body during a timestep, I don't see how it's generally
possible to analytically know how much of the respective
velocities/momentums came from where. That, and the floating point
imprecision would kill you ;-)
>
> Cheers,
>
> / h+
>
>
> -----Original Message-----
> From: ode-bounces at q12.org [mailto:ode-bounces at q12.org]On Behalf Of Tyler
> Streeter
> Sent: Monday, May 03, 2004 8:15 AM
> To: ode at q12.org
> Subject: [ODE] reverse timestep?
>
>
> Is it possible to run a simulation in reverse?  I was
> wondering if I could run my simulation for a while,
> then run it backwards from the end to the beginning.
>
> I thought maybe you could simply reverse the direction
> of all forces, torques, and velocities.  Would that
> work, or is there a lot more to it?  If it were that
> simple, it would be nice to add this functionality to
> ODE and be able to just pass a negative timestep to
> the solver and have it do this automatically.
>
> Tyler Streeter
>
>
>
>
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