[ODE] Angular-velocity autodisabling considered broken

[Andrzej Szombierski]

On Tue, 14 Sep 2004, John Miles wrote:

[...]
> 
> One of the biggest reasons that other engines like Novodex are ahead of ODE
> in the performance department is that they are smarter about autodisabling
> islands.  So this issue deserves some serious attention.  I've modified my
> ODE build to use a moving average of bb->avel over the last 5 timesteps for
> autodisable testing, and that helps a lot.  With the moving average in
> place, it's possible to find a compromise threshold value that suppresses
> both tipping problems and jitter.
> 
> I'm not saying that a moving average is the Right Way to address the
> problem, but *some* form of spike-filtering needs to be added to the
> angular-velocity check, or its usefulness is severely limited.
> 

I think that the problem that needs to be addressed is the jittering 
itself. Using the auto-disabling mechanism to reduce the effects may work 
well in some cases, but I think (or hope :) that other engines don't 
resort to such "hacks". Ideally, auto-disabling shouldn't affect the 
result of the simulation at all, only save some CPU time.

-- 
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