[ODE] Adding Negative Masses

[Jaap Stolk]

On 4/26/06, Auro <auro.ghosh at gmail.com> wrote:
> Negative mass? wouldn't that mean that the Inertia-Tensor would probably
> become negative-definite (or atleast wouldn't any more remain
> positive-definite). Shouldn't that bug certain laws of physics? Just
> wondering... would be nice to have someone pop in the proofs :).
>  Cheers,
>   -Auro

I think the idea was to remove part of the mass using a negative dMassAdd().
The resulting mass will still be positive, so I think physics should be ok.
There may be a problem with subtracting the last mass, since all that
remains are (accumulated) rounding errors, which can be anything.

If you go as far as actually ending up with a body with a negative
mass, that may be a problem. friction may cause it to accelerate etc.
:-)

It's simple to test. add two masses together, then add the last one
but with a negative mass, then look at the mass properties. should be
the same as the mass you started from.