[ODE] Returning to a previous state?

[Jon Watte (ODE)]

Andrew Arcilla wrote:

> Rigid Bodies: positions, velocities, quaternions, anything else?
> 
> Joints: angles, anything else?
> 
> World: anything?
> 
> Spaces: anything?

Actually, the joints would be set correctly if you set the bodies; you 
don't need to save them separately.

However, if you do things like change the collider/category bits 
dynamically, or change joint stop parameters, then those configuration 
values need to be restored to the right point in time. If you just set 
up your simulation and make it "go," adding contact joints and forces to 
bodies as your main way of affecting the system, then doing the bodies 
is all you need to do.

Btw: It's not on your list: angular velocity, in addition to linear 
velocity.

If you want perfect playback, there's also a random seed you need to 
re-seed for the StepFast solver.

Cheers,

			/ h+