[ODE] Values required to produce at least semi-realisticfrictionusing the default constant-force-limit model?

[Amund Børsand]

"John Miles" <jmiles at pop.net> skreiv:

> As far as I can tell, ODE's friction value is used only to determine whether
> or not something starts to move when gravity, or another force, acts upon it
> (static or "starting" friction).  What you're asking for is dynamic
> friction, which is the force that must be overcome to maintain steady motion
> of one body in contact with another.

> When someone runs the test_boxstack demo and sees spheres zooming losslessly
> off into the distance at warp 9, their first conclusion is that ODE is lame
> and broken.  Fortunately, I read the FAQ before I concluded that, but a lot
> of people don't.  I imagine that a general implementation of dynamic
> friction isn't as simple and generic as we're assuming it is, or Russ
> would've already added it just to save himself the "This thing is full of
> bugs" comments that show up every so often on the list.

Now you're mixing two very different physical problems. A rolling sphere
really has no friction, because nothing is sliding, that's where the
problem arises. This is actually a physical vs. mathematical problem,
i.e. a "problem" with the real world in relation to the mathematical
friction model, and not really a problem with O.D.E.

-- 
Amund Børsand <amund £ offroad . no>