[ODE] ODE rocks!

[Russ Smith]

> Two problems though:
> 1) It is very slow. The ball crawls towards the wall, but right when 
> the wall tumbles everything is super-fast. I can understand that 
> there must be hundreds of contact points and so this is probably 
> expected.

it might be instructive to look at the value of 'm' computed in
the dInternalStep_x2 function. the speed is O(n^3). maybe m is
excessive in your case?

> 2) Instability. [...]
>   ODE Message 3: LCP internal error, s <= 0 (s=nan)

i would very much like to find out the root cause of this problem -
it has been observed by a few other people but has not been isolated
yet. if you have a program that can *consistently* produce the
'LCP error' message, please send it my way (or post a link to the
list) so that we can fix this. thanks!

> Maybe I could write beginner tutorials or something like that?

tutorials would be very useful - something along the lines of
TrollTech's Qt tutorials (http://doc.trolltech.com/3.0/tutorial.html)
... i.e., this is how you make a world, now add a couple of bodies,
now add a joint etc - using the drawstuff lib, with pictures etc.

russ.

--
Russell Smith
http://www.q12.org