[ODE] unstable objects and the documentation

[Matthias Baas]

At 00:55 26.06.2003 +0000, Roel van Dijk wrote:
> > Am I correct in these assumptions? My only real issue with that is that a
> > gravity of -9.7 is next to useless, as car-sized objects end up 0.3 units
> > long, and thus gravity goes up to -97.0, to compensate.
>I don't see the relation between object size and gravitational pull... The
>gravity determines the acceleration of an object. -9.7 means that every
>object in the world has a continues acceleration. Every second the speed of
>an object is increased by 9.7 meters per second (or units).

You almost give the answer yourself. You have to be cautious to use units 
consistently. Obviously you set 1 unit = 1 meter and then you're right, the 
acceleration due to gravity is about 9.7 m/s^2 for any object. But if you 
regard 1 unit as 1 cm for example, then you have to adjust the value of the 
acceleration to 970 cm/s^2 (since 1m = 100cm). So it's not actually the 
*size* of an object that makes the acceleration change but the *units* used 
in your simulation world.

- Matthias -