[ODE] Newbie Question on Numerical Integration Method

Piotr Obrzut piotr_obrzut at o2.pl
Mon Jun 6 21:11:18 MST 2005


6 czerwca 2005 (19:10:54) Jon wrote:

JWO> The ODE solver uses a first-order forward integrator; it cannot switch
JWO> methods (as doing the LCP solver to a higher order would be 
JWO> significantly harder...)

JWO> If you have "wiggle" on resting bodies, the first thing to look at is
JWO> your time step. You should be using a fixed time step, and step enough
JWO> times to catch up to real time, but no more. The reason for this is that
JWO> bodies "resting" in ODE really are continually falling into the ground,
JWO> and getting a penalty force applied that pushes them out. If the time
JWO> step varies, they fall different lengths each timestep, and get 
JWO> different forces applied, which ends up causing instability.

Right I also need very stable simulation and I'm using min and max
steps count and when min == max then simulation is very stable, when
min << max then it tends to explode. Still I have some problems
with joint feedback forces: when min << max then they are very large,
when min==max they are much lower but still they sometimes go to
the large values. For me it is importand to have joint feedback forces
on constant low level - anyone could help me with that?

 Piotr Obrzut

More information about the ODE mailing list