[ODE] Adding Negative Masses

[Auro]

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

On 4/26/06, LR <logreg at free.fr> wrote:
>
> I've just tested and ... The geom with negative mass (encapsulated in a
> transformgeom) is falling and not collide with my plane ...
>
> Laurent.
>
> -----Message d'origine-----
> De : ode-bounces at q12.org [mailto:ode-bounces at q12.org] De la part de Bram
> Stolk
> Envoyé : mercredi 26 avril 2006 10:01
> À : Wesley Smith
> Cc : ODE Mailing List (E-mail)
> Objet : Re: [ODE] Adding Negative Masses
>
> Wesley Smith wrote:
> > Hi,
> > I'm curious is if it's possible to use dMassAdd() to add a negative
> > mass to a large mass and have the result be as if a chunk of that mass
> > went missing of the corresponding form.  For  example, if I do
> > dMassAdd(), combining 3 objects, and now want to take one of them
> > away.  Assuming that I've kept some record of the original small
> > body's mass, can I negate it's mass params in the dMass struct and
> > then call dMassAdd(&compositeMass, &body2) and have it behave as if
> > body 2 had been taken away?  I'm guessing yes, but I want to be sure.
> >
>
> Hey... nice idea.
> I can't say for sure, but my guess is that it works.
> You'll just have to try.
>
> It would be nice to have an example that simulates a helium balloon in
> ODE.
> Or a hindenburg? Cool! I just may try that in my spare time :-)
>
> Bram
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--
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- Aurobrata Ghosh -
+91-9873159692
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