Antwort: Re: [ODE] Forcing bodies to specified "non-physic-calculated" positions

[Martin C. Martin]

Marc.Schwellinger at Dornier.eads.net wrote:
> 
>>Martin C. Martin wrote:
> 
> 
>>>Marc, see if you can't change the "world" half of the attachment point
>>>every frame, and see if that works.
> 
> 
>>Now that I think about it: instead of attaching your joint to the world,
>>attach it to an invisible geom that doesn't collide with anything, and
>>that doesn't have a body.  Then set the position of that geom every
>>timestep.
> 
> 
> Thanks for your reply...Sorry but I read the Digest first.
> 
> How can I attach geoms to a joint? dJointAttach() accepts only dBodyID.

You're right, you can't.  I guess that's why I never thought of it before.

Try using a BallAndSocket joint attached between the desired body and 
the world.  Every timestep, update the "anchor2" field of the 
BallAndSocket joint to be the desired location in world coordinates. 
Crude ... but effective.

In other news, the Fixed joint now handles relative rotation as well as 
relative position.  It may take a few days to propagate to anonymous 
CVS.  Russ or Anselm, can someone regenerate the HTML docs from ode.doc?

Cheers,
Martin