[ODE] reverse timestep?

[Hellday]

Hi there!

I'm not so much into the details ODE's implementation but let me share 
my point of view.
I think it depends on what you want to achieve by reversing time in 
ODE. If you want some kind of replay then you should definitly go for 
the already posted recording of states but maybe you just need some 
kind of effect for a game.. whatever.

Generally as long as you have time symmetric equations for your system 
it will behave equally going forward and backwards in time.
So as long as there's no friction or other asymmetric components it 
should suffice to reverse (angular)velocities,  forces, torques, 
motors
at the time you want the inversion.

Of course numeriacal drift will ruin the playback but maybe you didn't 
want that anyway.

 I hope this was not too much of nonsense.

Holger