[ODE] Box stacking and ODE

[Adam D. Moss]

Nguyen Binh wrote:
>         Use Auto-Disable!
> 
>         Try to search the list for more. I had produced a very
>         stable boxes stacking with StepFast1 before.
>         
> WJvdL> I keep having problems stacking boxes in ODE, stacks of boxes just
> WJvdL> collapse after a while even if no force is applied to them, and the
> WJvdL> surfaces have infinite friction (so there should be no "shifting". The
> WJvdL> number of contact points doesn't seem to matter either.
> 
> WJvdL> Even the crash demo (from CVS) currently experiences this. The boxes keep
> WJvdL> pushing each other, until the whole heap collapses.
> 
> WJvdL> Can something be done against this?

Auto-disable/enable is a good thing, but it only hacks around
stacking stability -- as soon as the stack it wakened by being
touched it starts being prone to its own inherent instability
again.  A few months ago I mused about a StepFast which would
solve multiple contacts directly between the same bodies
simultaneously instead of serially, as something which would
achieve most of the scaleability of StepFast with most of
the stacking stability of StepSlow.  Another orthogonal
alternative is to special-case the handling of the collision
of 'stacked' primitives (hacks to detect that both objects
are aligned with respect to each other and gravity, etc).

Ideas are cheap though. :)

--Adam
-- 
Adam D. Moss   . ,,^^   adam at gimp.org   http://www.foxbox.org/   co:3