[ODE] objects in water

[Jon Watte]

> Here's a question: does penetration depth matter for buoyancy
> calculations?  I'm guessing that buoyant objects deep underwater would
> have more buoyant forces than objects close to the water's surface. 
> Even so, it's probably not worth the effort to simulate this in most
> real-time applications.

That's not true, except when you're partially intersecting the surface.

When something is partially in water, and partially above it, it only 
has as much floatation force as the part that's within the water. Once 
the thing is fully submerged, it exerts the maximum floatation it can, 
and pushing it further down won't exert more force (it's not a spring!)

In fact, once you go further down, the object may start to compress 
because of the high pressure, and thus its density goes up, and it gets 
less buoyancy further down. Divers can feel this at 10 meters!

Cheers,

			/ h+