[ODE] Consistency

[Peggy Skelly]

Yea - me too. Resetting positions and velocities works fine. In my case, I forgot
to remove the contacts generated during the last step of the prior simulation.

Peggy

>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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