[ODE] Joints flying off?

[Martin C. Martin]

Try reducing your step size, that's the value you pass to dWorldStep().

- Martin

Karl Meissner wrote:
> 
> Thanks, that helps a lot. I thought anchor was in body coordinates...
> The pole now move correctly if there is a single body.
> but....
> I still run into situations where the joints 'break'.  If I drop a the bodies
> into a pile eventually (after about 5 or 6 ) one of the poles 'breaks' and falls off.
> Maybe the contacts overwhelm the hinge code? Seems like a bug....
> 
> --- "Martin C. Martin" <martin@metahuman.org> wrote:
> > My guess is you're setting the anchor in the wrong place.  You need to set
> > it, in world coordinates, to the location where the pole meets the box
> > (assuming that's where you want the hinge to be.)  Come to think of it,
> > you also need to set the hinge axis properly, in the world coordinate
> > frame.
> >
> > - Martin
> >
> > Karl Meissner wrote:
> > >
> > > Hi I am new to ODE so I might be making a newbie mistake.
> > >
> > > I am trying to set up a simple situation.  I want to have a 1x1x1 square cube that has a 1
> > meter
> > > pole attached  to the center of its top face.     The problem I have is that the pole’s bottom
> > > does not stay attached to the cube....it drifts away after collisions.
> > >
> > >  I create the cube and pole,
> > >   set their positions so the bottom of the pole just touches the cube
> > > create a hinge
> > > attach the two bodies to the hinge
> > >
> > > Then I run the sim.    The cube and pole drop down and hit the ground and then the pole drifts
> > > away. Visually the pole is affected by the cube but it does not keep its bottom in a fixed
> > > relative position.
> > >
> > > Also, if I don’t set the anchor point, the bodies spin like mad.
> > >
> > > I have tried setting the various joint parameters such as CPM to 1 or 0 and the stop
> > parameters.
> > > These seem to help somewhat but still the pole does not stay attached.
> > > It is particularly bad if I create a bunch of these bodes and cause them to collide with each
> > > other.
> > >
> > > So I guess my question is there a way to attach a joint so the pole will not 'drift'.
> > > Is it some combination of hinge parameters?
> > >
> > > Karl
> > >
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