[ODE] Consistency

[Henri Hakl]

Yea - I've got it worked out... setting Position and velocity for bodies and
joints works perfectly as a "reset". Completely consistent.

The problem was (in my case) that I didn't properly reinitialize AIs (I
thought I did... ahem...)



----- Original Message -----
From: "Henri Hakl" <henri@cs.sun.ac.za>
To: <ode@q12.org>
Sent: Tuesday, March 18, 2003 8:30 PM
Subject: Re: [ODE] Consistency


> You can set joint velocities and maxforces to zero with the following
> technique:
>
> dJointSetAMotor(jointID, dParamVel, 0);
>
> Though if maxforces are constant I don't think they need to be reset...?
The
> velocity can easily be fixed to zero - but I set them with each simulation
> step anyway, so it shouldn't be necessary to set them to zero beforehand.
> Still it seems there is some area of inconsistency somewhere in my
> Simulation that I haven't been able to figure out. We'll have to see...
>
>
> ----- Original Message -----
> From: "Peggy Skelly" <mxs70@po.cwru.edu>
> To: <ode@q12.org>
> Sent: Tuesday, March 18, 2003 5:40 PM
> Subject: Re: [ODE] Consistency
>
>
> > That's probably the problem (non-zero joint feedback right after
> reinitialization - when there should be zero feedback - seems to confirm
> it). But how do I reset the joint velocities? I thought that resetting the
> bodies to their initial positions and zero velocities would carry the
joints
> along, and they'd also be back at their initial position with no velocity.
> >
> > Peggy
> >
> > >How about joint velocity and fmax?
> > >
> > >Just a thought,
> > >David
> > >
> > >> Does your consistency issue have anything to do with the earlier
> > >> "Reset" question? I also wanted a quick way to reset the initial
> > >> conditions of a simulation, and I liked your solution of just
> > >> resetting the positions, quaternions, linear and angular velocities.
> So
> > >> I tried that out over the weekend. I found that after resetting,
> > >> although all the positions and velocities were correct (as i set
> > >> them), the simulation proceeded differently. Is there something else
> > > > that I need to reinitialize?
> > > >
> > > > Peggy
> > > >
> > > >>Hi - just a quick question, is ODE deterministically consistent? In
> > >>> other words will it (even in complex systems) always produce the
same
> > >>> results?
> >
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