simtk.org • Invalid MobilizedBodyIndex error

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Invalid MobilizedBodyIndex error

Posted: Wed Dec 21, 2022 2:27 pm

by crubow

Hello,
in the XML .osim model file, in attempting to add a Body to an existing model, I get the error:

Attempting to assign an invalid SimTK::MobilizedBodyIndex in Object 'spine_offset' of type PhysicalOffsetFrame. Thrown at PhysicalFrame.cpp:73 in setMobilizedBodyIndex().

The Body I've attempted to add is:

Code: Select all

<Body name='spring_ground'>
	<mass>1</mass>
</Body>

OpenSim runs fine without said Body but with Body throws said error. The error seems addresses the area in the XML directly after the Body I'm trying to add in.

Re: Invalid MobilizedBodyIndex error

Posted: Mon Jan 23, 2023 2:40 pm

by ongcf

It's possible that this is a more general error if this new Body that you've added does not have a corresponding Joint that tells the Model where this Body should be attached to. More info on how Models work can be found on our documentation page OpenSim Models. It will also be helpful to look through other Models for examples and check the Joints in those Models to help guide your work too.