Hello,
I am trying to scale Scapulothoracic Joint model but after scaling the scapula seems to go part into the ribs. Has anyone here any idea why that might be happening? Also if anyone has got it successfully done can you please sharing the scaling factors, so that I may get the idea.
Sorry but I am new to OpenSim and any help would be really appreciated
Thanks & Regards,
Shivangi Giri
Scaling Scapulothoracic Joint Model
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Shivangi Giri
- Posts: 51
- Joined: Sun Jul 02, 2017 3:04 am
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Thomas Uchida
- Posts: 1792
- Joined: Wed May 16, 2012 11:40 am
Re: Scaling Scapulothoracic Joint Model
To scale the Scapulothoracic Joint, I believe you will need to redefine the SpatialTransform that defines the kinematics of the joint. Have you read the paper and downloaded the code from the associated SimTK project page?
Seth A., Matias R., Veloso A.P., Delp S.L. A Biomechanical Model of the Scapulothoracic Joint to Accurately Capture Scapular Kinematics during Shoulder Movements. PLoS ONE, 11(1): e0141028, 2016. http://nmbl.stanford.edu/wp-content/upl ... th2016.pdf
"Model of the Scapulothoracic Joint" SimTK project page: https://simtk.org/projects/scapulothoracic
Seth A., Matias R., Veloso A.P., Delp S.L. A Biomechanical Model of the Scapulothoracic Joint to Accurately Capture Scapular Kinematics during Shoulder Movements. PLoS ONE, 11(1): e0141028, 2016. http://nmbl.stanford.edu/wp-content/upl ... th2016.pdf
"Model of the Scapulothoracic Joint" SimTK project page: https://simtk.org/projects/scapulothoracic
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Shivangi Giri
- Posts: 51
- Joined: Sun Jul 02, 2017 3:04 am
Re: Scaling Scapulothoracic Joint Model
Hello Tom,
Thank you for your reply. There are few things I do not understand which needs to be done after scaling the model. For instance, in the paper by Ajay et al it say "The remaining parameters were determined by minimizing the squared errors between model and subject marker locations from nine poses evenly selected from each task. For each task the ellipsoid orientation and radii were adjusted because marker errors were most sensitive to these parameters and account for rib-cage expansion and spinal bending/twisting differences between the tasks." I do not understand what this exactly means.
I have written to Ajay regarding the issue I am facing with scaling and waiting for his reply. In the meantime could you please help me in understanding the steps I need to do after scaling, better.
Regards,
Shivangi
Thank you for your reply. There are few things I do not understand which needs to be done after scaling the model. For instance, in the paper by Ajay et al it say "The remaining parameters were determined by minimizing the squared errors between model and subject marker locations from nine poses evenly selected from each task. For each task the ellipsoid orientation and radii were adjusted because marker errors were most sensitive to these parameters and account for rib-cage expansion and spinal bending/twisting differences between the tasks." I do not understand what this exactly means.
I have written to Ajay regarding the issue I am facing with scaling and waiting for his reply. In the meantime could you please help me in understanding the steps I need to do after scaling, better.
Regards,
Shivangi