Output GRF files from ID do not contain moments

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Duncan Lee
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Joined: Thu Sep 14, 2023 10:15 am

Output GRF files from ID do not contain moments

Post by Duncan Lee » Mon Jun 17, 2024 1:29 pm

Hello,

I noticed that when I look at the ground reaction force output files from inverse dynamics they do not contain moments, even though my input files do. Does this mean that AddBiomechanics is not using the moments for inverse dynamics?

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Nicholas Bianco
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Joined: Thu Oct 04, 2012 8:09 pm

Re: Output GRF files from ID do not contain moments

Post by Nicholas Bianco » Thu Jun 20, 2024 10:03 am

Hi Duncan,

We do use GRF moments during the dynamics fitting step. Where are you not seeing them?

-Nick

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Duncan Lee
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Joined: Thu Sep 14, 2023 10:15 am

Re: Output GRF files from ID do not contain moments

Post by Duncan Lee » Tue Jun 25, 2024 9:14 am

Hi Nicholas,

In the ID output GRF file I am getting, the GRFs and COPs are populated but the moment columns are not. I have attached an example file.

Thanks,
Duncan
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walking_0p75_vsa_01_filtered_segment_0_grf.mot
(459.46 KiB) Downloaded 34 times

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Nicholas Bianco
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Re: Output GRF files from ID do not contain moments

Post by Nicholas Bianco » Tue Jun 25, 2024 10:54 am

Hi Duncan,

If your original GRF files contained moments, they should get propagated to the output. Can you upload your input GRF data file?

Best,
Nick

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Duncan Lee
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Re: Output GRF files from ID do not contain moments

Post by Duncan Lee » Wed Jun 26, 2024 2:35 pm

Hi Nicholas,

The original GRF file is too large but I have attached an example portion. All the data is structured the same way.

Thanks,
Duncan
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example_grf.mot
(225.52 KiB) Downloaded 33 times

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Duncan Lee
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Re: Output GRF files from ID do not contain moments

Post by Duncan Lee » Mon Jul 01, 2024 3:43 pm

Hi Nicholas,

I was wondering if you have any insights or suggestions on what to do about this? Do you know if it is successfully using the moments in ID given the outputs? If it has to do with the format of my input file I can try different formatting.

Also, is there any way to get the calculated joint centers the AddBiomechanics uses?

Thank you,
Duncan

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