[ODE] Inconsistent joints
Jon Watte (ODE)
hplus-ode at mindcontrol.org
Fri Sep 1 10:33:56 MST 2006
Roland Plüss wrote:
> dReal k = info->fps * erp;
> info->c = k*j->contact.geom.depth;
> It is assumed that the depth is recovered gradually over the entire
> simulation step but this is not true. After the "New Joint Guide" the
> c-value in the contact joint is calculated like this:
> c = ( ERP / s ) * nT * [ ( p1 + a1 ) - ( p2 + a2 ) ]
ERP/s is the same as the "k" calculated in the code.
It appears nT happens to be 1 for the contact joint.
((p1+a1) - (p2+a2)) is the same as contact.geom.depth for the case of
the collsion joint.
So, what's the difference you're implying? ODE is a first-order
integrator, so it doesn't use multiple derivatives for a single step,
like you'd see in something like R-K4.
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