[ODE] movement force conversion

[Hampus Soderstrom]

Hi,

How can I calculate this if I only want to use joint motors?

For instance if I want a joint to have 30 degree angle after
10 timesteps.

cheers

/Hampa

2005-03-16 kl. 00.25 skrev Jon Watte:

>
>> that is what interest me in longer time, but now before any
>> research: it is possible to turn stored forward kinemtic animation
>> into forward dynamics?
>
> Absolutely.
>
> I'm assuming a rigid skeleton with ball joints, but you can
> generalize to any kind of joint that your animation uses:
>
> For each frame, pose your animation skeleton the way the
> animation wants it for the NEXT frame in time.
>
> Then, for each body in your dynamics skeleton, measure the
> angle relative to its parent, and compare to the animation
> skeleton. This gives an angle error in parent-relative space
> for each bone.
>
> Now, calculate the torque necessary to move the body to the
> desired angle in the next timestep (or in some amount of
> future time, of you want a more dampened fit). Optionally
> apply maximum joint torque constraints. Apply this torque to
> the body. Step the world. Yay, you're done!
>
> For position constraints, substitute "movement" and "force"
> for "angle" and "torque".
>
> If you want to support external forces like holding things,
> you should also keep an error accumulator, and add in some
> multiplied factor of that error to your force, so that you
> will compensate for being off in a specific direction for
> many steps.
>
>
> The Wiki says that all pages are read-only, so I can't add
> this information here. (It should go in the Tips and Tricks
> section).
>
>
> Cheers,
>
> 			/ h+
>
>
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