[ODE] Running ODE backwards in time?

[Adam Moravanszky [NovodeX]]

Exactly. 

--Adam

Megan Fox wrote:

>This is probably a ridiculous question, but I'm assuming you would
>have physics turned completely off for the replay (and have a movement
>vector/orientation vector saved out for each keyframe) - not plugging
>in the keyframe'd reverse velocities and so on.
>
>-Megan Fox
>
>On Mon, 15 Nov 2004 13:16:34 +0100, Adam Moravanszky
><adam.moravanszky at novodex.com> wrote:
>  
>
>>Good point.  You would have to make sure that you never completely stop
>>-- you would have to maintain a tiny residual velocity.  Of course with
>>float rather than real numbers you would have data loss anyway as values
>>get truncated.  Anyway, this discussion is only theoretical anyway, in
>>practice there is no way you could pull this off.  In the real world you
>>would have to record motion keyframes when simulating forward and
>>interpolate backwards -- just like in games that have a rewindable
>>instant replay feature.
>>
>>--Adam
>>
>>
>>
>>Alen Ladavac wrote:
>>
>>    
>>
>>>I'd say that this is insolvable for general case with dynamic friction. If a
>>>box slides on a horizontal plane and comes to rest, how do you calculate
>>>where it was supposed to come from, from its position only? ;)
>>>
>>>
>>>----- Original Message -----
>>>From: "Adam Moravanszky" <adam.moravanszky at novodex.com>
>>>To: <mtoussai at inf.ed.ac.uk>
>>>Cc: <ode at q12.org>
>>>Sent: Monday, November 15, 2004 10:36
>>>Subject: Re: [ODE] Running ODE backwards in time?
>>>
>>>
>>>
>>>
>>>      
>>>
>>>>   mtoussai at inf.ed.ac.uk wrote:
>>>>
>>>>Hi there!
>>>>
>>>>I need to run some simulations backwards in time (for some planning
>>>>algorithms..). I know I could do this by inverting all dynamic properties
>>>>((angular) velocities, accelerations, etc.) of the system and running ODE
>>>>forwards. But is there a simpler way? Just setting a negative time
>>>>
>>>>
>>>>        
>>>>
>>>interval in
>>>
>>>
>>>      
>>>
>>>>a step function doesn't work.
>>>>
>>>>Thanks!
>>>>Marc.
>>>>_____________________
>>>>
>>>>
>>>>
>>>>        
>>>>
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>>    
>>
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