[ODE] problems with amotor

[jnilson_99 at yahoo.com]

"I notice most questions on AMotors don't get
responded to by this 
forum, and others, like http://ode.petrucci.ch/, don't
have much to offer.
Is it widely accepted that this class is broken?"

well, i've struggled with AMotor's for about 3 weeks
now and have gotten nowhere. i've gotten them to do
the most limited of tasks. but when "pushing the
envelope" like using an amotor in dAMotorUser mode
with a ball and socket joint everything falls apart.
the few examples in ode/test don't provide any usefull
information. i keep posting questions to this bboard
with no answer.

sadly, this makes me think ode is slowly dying. at
least those of us trying to learn amotors can get no
help anywhere.

Russ, a little help?

john
--- Jason Mallios <jmallios at cs.brown.edu> wrote:
> I notice most questions on AMotors don't get
> responded to by this forum,
> and others, like http://ode.petrucci.ch/, don't have
> much to offer.
> 
> Is it widely accepted that this class is broken? 
> I've tried to implement
> most examples from years of community correspondence
> and none have worked
> as expected.
> 
> Outstanding issues include:
> 
> - How do you get a non-zero vector representing the
> automatically-calculated axis 1 in Euler mode?
> 
> - How can you get a relative angle between two Ball
> and AMotor-connected
> bodies in User mode, since dJointGetAMotorAngle
> returns the initial
> angles only in this mode?
> 
> - When or will dJointGetAMotorAngleRate be
> implemented and added to an
> official release?
> 
> - Given a world-space torque, calculated as a single
> vector, how can you
> reliably apply it to dJointAddAMotorTorques without
> euler-angle gimbal
> lock?
> 
> Jason Mallios
> 
> On Sun, 8 May 2005, Smoel zonder snor wrote:
> 
> > Hi
> >
> > I'm working on a simulation of lego-models and I'm
> having the
> > following problem: I create some amotors in Euler
> mode and I try to
> > rotate them ( rotation around 1 axis only ).  When
> the one axis I
> > rotate around crosses the origin, it works
> perfectly.  When the axis
> > doesn't cross the origin, it rotates around the
> axis parallel with it,
> > but which crosses the origin ( so it rotates
> around the direction of
> > the axis ).  As I understood from
> > http://ode.org/ode-latest-userguide.html the only
> thing I have to do
> > to make an amotor rotate is enter the axes, attach
> the amotor to the 2
> > concerning body's, and create a hinge joint
> between the same 2 body's.
> >  This doesn't seem to work.
> >
> > Could this be the consequence of the following:  I
> place all of my
> > body's in the origin, so I get a relative position
> and rotation during
> > the simulation to work with.
> > If this is the cause of the problem, I don't
> really know how to solve
> > it, because there can me more than one amotor in a
> body in my
> > structure, so I can't set the body position to the
> centre of the
> > amotor
> >
> > Any help would be welcome.
> >
> >
> > thx in advance
> >
> > _______________________________________________
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> > ODE at q12.org
> > http://q12.org/mailman/listinfo/ode
> >
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