[ODE] ODE with non-penetration constraint

[Ke]

ODE uses first-order integrator so it uses "velocity -
impulse/force" model to solve for MLCP problems. But
due to the approximations of ODE or time-step choise,
the non-penetration constraints some time may be
voilated. I don't think ODE has some kind of impact
model here. If yes,the non-penetration constraints
will exactly hold.

Ke
--- Huang Rubby <rubbybaby at gmail.com> wrote:

> Thanks.
> So such penetration was coming from the "bad"
> solution of LCP solver, which
> will generate a bigger normal contact forces, in my
> case the normal contact
> force
> will be more than m*g,  to  bounce back such 
> penetration.
> Please point me out if my understanding was not
> right.
> As for the "soft" contact parameters - erp and cfm,
> how are they related to
> the
> LCP?
> 
> Ruby
> 
> On 7/11/07, Huang Rubby <rubbybaby at gmail.com> wrote:
> >
> > Hi All,
> > on ODE manual, it says, "ODE has *hard* contacts.
> This means that a
> > special non-penetration constraint is used
> whenever two bodies collide."
> > But in my simulation example, which basicly was a
> ball rolling on ground,
> > somehow, I read out the contact point position and
> found the Z - direction
> > (vertical)
> > coordinates were -0.005. Which means the contact
> point was underground.
> > How did it happened? Since ODE has Hard contacts
> for each collision.
> > Any way to avoid such penetration? Thanks.
> >
> > Ruby
> >
> > _______________________________________________
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> http://ode.org/mailman/listinfo/ode



       
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