Re: [ODE] controling joint forces

piotr_obrzut at piotr_obrzut at
Wed Sep 14 09:51:05 MST 2005

---- Wiadomość Oryginalna ----
Od: Jaroslav Sinecky <jsinecky at>
Do: Piotr Obrzut <piotr_obrzut at>, ode at
Data: Tue, 13 Sep 2005 17:32:51 +0200
Temat: RE: [ODE] controling joint forces

> I'm not exactly the ODE experienced one, but as no other replays,
I tell you
> my opinion based on part of ODE code I have seen.
> I think it's not easy to implement what you want (by the way what
for do you
> need to add joint forces only above certain value?).

It is for replaing animation with forces, in my previous semester I
got satisfacting results in that, but I couldn't control only joint
forces: all the time I was adding forces to my bodies to meet
animation conditions, igonoring all other forces, to the moment they
will be greater than "character strength" (which worked similar as
Endorphins "active pose"). Result (I can send you if you want) whas 
not so perfect b/c joints was still adding their forces in the next
step deforming motion.

 Joints actually don't
> simply add forces to bodies, joint forces in every island of
bodies are
> interdependent, when one joint applies more force, some other
joint may
> apply less force, so that joint constraints are maintained. That's
what the
> LCP solver does.
> Maybe some similar trick as for friction limit contact could be
used, but I
> don't know how this is done.

I was thinking after reading doc's about joints that there must be
certain place for calculating its equation (where I wanted to put
this callback). 


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