[ODE] Chain Simulation

[achaudhry]

hi , 
while trying to simulate a chain pull up and drop down from a point, 
the following were the values being used, 

chain has 2 links

each link has size 3.4 units
and are connected uing a ball and socket joint. 

The upper link is connected to some other fixed object and the lower lnk is
hanging freely in air under gravity. 

as suggested earlier, i dropped the link further down by just changing the
point on the upper capsule by which it is connected to the fixed point. and if
required a new link is added at runtime. 

the rope dron down rate is 0.0002 units for every key pres sand it works fine. 
but while pulling the rope up using similar logic, after pulling the rope up
by 0.0002 units , if i run the simulation for one time step(0.05) the chain
instead of moving up comes down. 

But if i pull up by 0.002*100 = 0.2 units then it works fine. Some how i
couldn't grasp the logic of why this is happening, please  let me know if any1
has the idea. 


Regards
Amber