[ODE] mu = dInfinity, surfaces still slide

[Keith Wiley]

With mu set to dInfinity, I would expect a contact joint to allow  
absolutey no slide.  This is straight from the docs:

"0 results in a frictionless contact, and dInfinity results in a  
contact that never slips."

Other parameters can change this, such as slip1, slip2, and maybe  
dContactApprox (I'm not really sure about that one), but I'm not  
setting these parameters for the contact in question.  I'm just  
setting mu to dInfinity:

	contact[i].surface.mode = dContactMu2;
	contact[i].surface.mu = dInfinity;
	contact[i].surface.mu2 = dInfinity;
	dJointID c = dJointCreateContact (gWorld, gContactGroup, contact+i);
	dJointAttach (c, dGeomGetBody(o1), dGeomGetBody(o2));

I'm not really using mu2 for anything since it's the same as mu (the  
default is for mu2 to be mu if there is no mu2 set), but I have to  
set SOMETHING in mode, so I use mu2.  At any rate, why would a  
contact joint set up as above, slide at all?

Thanks.

________________________________________________________________________
Keith Wiley         kwiley at cs.unm.edu         http://www.unm.edu/~keithw

"I do not feel obliged to believe that the same God who has endowed us
with sense, reason, and intellect has intended us to forgo their use."
                                            --  Galileo Galilei
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