[ODE] Making simulation speed independant from computer speed

[Kevin Frugier]

Hello,

I am working again with ODE. The first time was for a protein 
interaction simulation, the second time for a robot simulation.
This time I'm doing some test for a game my association is developping.
The game is a mario-kart like but that's not the point here.

Using examples and documentation I understand more and more how ODE 
works but I still have a problem to understand the unit used in dWorldStep.
In the mailing list I have seen recently someone saying he used 0.01 or 
some value like that.
In the famous "FreeFall buggy demo 
<http://freefall.freehosting.net/downloads/buggydemo.html>" it uses 0.02 
or 0.03 depending of the elapsed time since the last frame.

My first question is : what is the unit of the stepsize ?
My second : what kind of calcul should I do to make the simulation speed 
being the same on others computers, for example if I get the time 
elapsed in millisecond.

I think that is the typical question when you want to develop a game not 
only for you, so I hope my question is not too stupid.

Thank you.

Kevin