[ODE] Large mass and accuracy

[Jon Watte]

> dimensions of input values. But what do you do when you want to connect a
> wheel with 50 kg mass to a car/tank body with 50,000 kg mass and keep a
> stable simulation? Didn't find a proper solution so far.

Divide forces and masses by, in this case, something in the 
500-1000 range. That would give you a 50 unit tank and a 0.05 unit 
wheel; still not ideal, but better than 50000. If your simulation 
uses type double (not float) then it might be OK at that point. 
Make sure to scale forces and torques accordingly.

For games, I would first do this scale, then take the square root 
of the mass values to make it more stable at the cost of some 
realism.

Cheers,

			/ h+