[ODE] Copying a dynamic/collision space

[B.E.D.Ellis-00 at student.lboro.ac.uk]

In the current project I am working on I need to be able to look at the
dynamics world one or more steps back from the current one. How do I create
a new dynamics world with a copy of all the rigid bodies and joints at the
beginning/end of each step?

    Regards,

        Ben