[ODE] Adjusting a body's mass

[Jon Watte]

Mass translation is ignored by the body, so you have to caculate what the 
actual center of gravity is, and put the body there (typically by offsetting 
any geoms and joint attachment points from the body).

A second, inferior, solution is to add a number of bodies to the main body, 
all attached with fixed joints. This will perform worse, and lead to less 
stability in the simulation.

Cheers,

			/ h+

> In my particular case, I want to add and remove "weight" in certain places on my vehicle 
> chassis such as a fuel tank, or a driver, or a rocket launcher.  My hope is that I can 
> make the vehicle front or back "heavy" and it will affect the steering.