Re: [simspark-devel] ODE Composite bodies

[Joschka B. <jos...@am...>]

Hi Sander,

On Feb 7, 2008, at 7:37 AM, Sander van Dijk wrote:

> I've got it to works now. In the attached archive is a working patch  
> plus a soccerbot that has a composite body torso (with a somewhat  
> skewed mass distribution). It took some time to get translated and  
> rotated geometries in the right place, but that seems fine now. As  
> long as a Collider node uses the new setLocalPosition to set the  
> position relative to its body's center.

Great! Thanks a lot for the patch and the model.

> As you also pointed out, the mass distribution of composite bodies  
> still should be sorted out.

Right.

> Now for the bad news: the 'thigh slapping' LCP erors that I  
> mentioned in my first email still happen.. It seems it weren't the  
> joint stops causing the excessive forces after all. My next bet is  
> that it is caused by the sharp edge of the hand hitting the angled  
> part of the torso's lower part too hard, which I think is only  
> preventable by reducing motor force.

Sorry, I completely forgot *d'oh*! The hands were changed from the 055  
model to the 056 model, too. They also use fixed joints in the 056  
model to glue together the 3 boxes that make up the hand. These are  
most likely what causes the trouble now. Could you please check this?

> PS when I run the simulation with this patch, ball and players don't  
> collide with the goals anymore. This is due to collider.cpp in the  
> simspark cvs where the use of a default collision handler is  
> commented out.

OK, so can we solve this using the RSG files then?

Cheers,
Joschka