[ODE] Joints flying off?

[Martin C. Martin]

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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