Inverse Kinematics issues

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Jonathan Walter
Posts: 8
Joined: Fri Mar 28, 2008 7:05 am

Inverse Kinematics issues

Post by Jonathan Walter » Mon Aug 01, 2011 1:17 pm

When running the Inverse Kinematics tool from the OpenSim 2.3 GUI, I run into a couple of issues:

1) Results do not include the first time frame of the TRC marker file

2) Prescribing coordinate values (under the 'weights' tab) does not work for "From File", Default Value" and "Manual Value". I have also tried adjusting the weights with no luck.

3) If I enable 'clamp to bounds' for some coordinate in the coordinates window, IK does not actually stay within the desired bounds. However if I enable 'lock value' for some coordinate, the IK tool will keep this coordinate locked at that value

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Ayman Habib
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Joined: Fri Apr 01, 2005 12:24 pm

RE: Inverse Kinematics issues

Post by Ayman Habib » Mon Aug 01, 2011 2:02 pm

Hi Jonathan,

The issue with first first frame existed in an earlier beta release but is fixed in the latest beta release AFAIK (what build are you using?)

Clamping should have no effect, the bounds on the coordinate are used.

For the other issue, please file a bug report and attach the model, setup and data files and we'll investigate.

Best regards,
-Ayman

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Jonathan Walter
Posts: 8
Joined: Fri Mar 28, 2008 7:05 am

RE: Inverse Kinematics issues

Post by Jonathan Walter » Tue Aug 02, 2011 8:23 am

I am using 2.3.0b4.
When I use 2.2 release, the frame issue goes away and I can specify coordinate values under the 'weights' tab.
I will install the latest beta release and see if these things work in it.
When you saw the bounds on the coordinates are used, do you mean that the IK tool will always try to find coordinate values that are within the specified ranges of that coordinate?

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