[ODE] Running ODE backwards in time?

[mtoussai at inf.ed.ac.uk]

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.