Experimental and virtual marker positions

Provide easy-to-use, extensible software for modeling, simulating, controlling, and analyzing the neuromusculoskeletal system.
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Jobin Geevarghese ThampI
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Experimental and virtual marker positions

Post by Jobin Geevarghese ThampI » Tue Jun 21, 2022 9:19 am

Hi, i was trying to scale the model and when I scaled it, both experimental and virtual markers got placed away from the subject rather than being on the model..what is the cause of this issue?....Also, both experimental and virtual markers are pretty close to each other in that...so that means scaling is done perfectly?
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scaling doubt.png
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Last edited by Jobin Geevarghese ThampI on Wed Jun 29, 2022 4:20 pm, edited 2 times in total.

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Thomas Uchida
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Re: regarding scaling

Post by Thomas Uchida » Sat Jun 25, 2022 11:24 am

Based on the image, it is difficult to determine what happened. However, it looks like there might be three models open in the image: one with blue muscles (which has its own pink model markers), one with red muscles, and one whose skeletal geometry is invisible. If only two models are open, then perhaps the parent body was incorrectly defined for some of the model markers?

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Jobin Geevarghese ThampI
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Re: regarding scaling

Post by Jobin Geevarghese ThampI » Sat Jun 25, 2022 1:52 pm

incorrectly defined in the sense, are you talking about naming the markers?

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Jobin Geevarghese ThampI
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Re: regarding scaling

Post by Jobin Geevarghese ThampI » Sat Jun 25, 2022 3:29 pm

Also I have one doubt, for determining scale factors is there any way in which we have to select the markers, for example:- do we we have to select the markers present on bony ends?

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Jobin Geevarghese ThampI
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Re: regarding scaling

Post by Jobin Geevarghese ThampI » Sun Jun 26, 2022 3:21 pm

Hi sir, when i again tried scaling, the virtual markers are placed correctly on the model, but this time the experimental markers are getting place outside the body
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Thomas Uchida
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Re: regarding scaling

Post by Thomas Uchida » Sun Jun 26, 2022 4:45 pm

If scaling was completed with low marker error, then the issue may just be the "model offset" setting. Please see the "Object-Specific Commands" page in the documentation (https://simtk-confluence.stanford.edu:8 ... c+Commands) and search for "model offset".

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Jobin Geevarghese ThampI
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Re: regarding scaling

Post by Jobin Geevarghese ThampI » Wed Jun 29, 2022 9:19 am

Hi sir, I tried the model offset still it isn't working, between how can we know about the marker errors, like whether its low or not?. Are you talking about the marker error appearing in the messages window?. If yes, i think iam having a high marker error 1.32 m in RGTR..so inorder reduce that i have to again move my virtual markers by refering to the images right?. Also, i think since experimental markers are lying away from the virtual markers i am getting a huge marker error. Also, if I click preview experimental data markers are coming in the same position rather than displaying in the front of the screen. While opening .osim model it is getting opened correctly. Even if i perform model offset correctly the markers are moving the same distance. Also, when I am performing transform option in Marker its changine its x y z coordinates, but still it cant perfectly fit into the model as a result i am getting high marker errors
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doubt1.png
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opensim doubt 2.png
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