Torso Geometry and MoBL_ARMS Model
Posted: Mon Apr 01, 2019 12:26 pm
Hello,
I have a full body model with a limited muscle set around the elbow and forearm. I have been trying to port the muscle set and geometry from the MoBL_ARMS model onto the model to include more shoulder muscles, but have had some problems.
My original model was just a ball and socket shoulder joint, so I have added the clavicle and scapula bodies, along with the necessary joints, constraints, and the muscles. The problem is that the "torso_offsets" used do not work as expected in my model. Using the offsets from the MoBL_ARMS model, all of the bodies and muscles are offset from a different position. I also noticed that the "torso_offset" used to establish the shoulder joint in my original model is (0.003155,0.3715,0.17) vs. the sternoclavicular joint offset in MoBL_ARMS which is (0.006325,0.00693,0.025465). The Y-value is hugely different which I think is part of the issue.
![Image](https://lh3.googleusercontent.com/SZNKGH7wmZ7eoc5R6q0QFNBpwV63U_EEqXDic3nPITZNphz8H_ZAL3sB8iSWZlXWJItWvI75TQvN_Q-fX87xskZ5kBerXKPdboX0VIF-rztIMmZoRpytk62AKn5BKn9K8DSCzg3DG2QKJsP6brVwKTUe6RiqE26N2JVivz854gRwgliWo4EiUhf_z_ACMob8aWezIqsNeU55MxSpcADaIkDBAzyZuUHeZUpot5Fl_ze3chW0H0v0H8rMKrTq1Tjrg3KSce-w8ugFVwByR8HcRC3PxetUJBWmzS7zzrMmDr29EY4DUBfO2IofOWH_Sj-2SRRE9kMkQ8qBK5f0KyQU723oYH1bRbpNPNvzlTWsacUVl8Jg-D9tfMdSSYX15yfOGpWcWXUKnRoigmOfeMSbKSN_Zg1RrvJFu7BpATfWZnsNOMQpAYHk67RB28uwu0jE8zLjM4ulNmCpAmco_5voa9h3YQAGIZ0KDiu8-sHTOyTO5G-yXRlMbvWcfcAVGarjpV1ObND88EIFTsXfnRX2mcJT0NEn0N_Hl_sbL2iGYnByIEkmEifeKY2MFPvVsrVQfNAbu7QQ4L0T2Iz6iRjgaR3fLwRELQr2PO50eZjq7qzJWACG5g3CgkTYM-An5XAAmPRxavj2co9ZcZM-EEhycWbFxqTtiYmd=w672-h578-no)
Opening the two models in OpenSim, my model appears in the visualizer with the pelvis halfway through the ground plane, where as the MoBL_ARMS model appears mostly blow it, with the suprasternal notch just appearing above the ground plane (see attached)
My thoughts:
Any help is greatly appreciated, I think I just need to figure out what the "torso_offset" needs to be so I can apply it to the joints and muscles. I attached a couple extra screenshots for reference.
Thanks,
Joe Marsh
I have a full body model with a limited muscle set around the elbow and forearm. I have been trying to port the muscle set and geometry from the MoBL_ARMS model onto the model to include more shoulder muscles, but have had some problems.
My original model was just a ball and socket shoulder joint, so I have added the clavicle and scapula bodies, along with the necessary joints, constraints, and the muscles. The problem is that the "torso_offsets" used do not work as expected in my model. Using the offsets from the MoBL_ARMS model, all of the bodies and muscles are offset from a different position. I also noticed that the "torso_offset" used to establish the shoulder joint in my original model is (0.003155,0.3715,0.17) vs. the sternoclavicular joint offset in MoBL_ARMS which is (0.006325,0.00693,0.025465). The Y-value is hugely different which I think is part of the issue.
Opening the two models in OpenSim, my model appears in the visualizer with the pelvis halfway through the ground plane, where as the MoBL_ARMS model appears mostly blow it, with the suprasternal notch just appearing above the ground plane (see attached)
My thoughts:
- The MoBL_ARMS model references the torso as the ground plane, where as in my model the pelvis is referenced as the ground plane. Could that be throwing off the offsets?
- Looking at the geometry files, I found that MoBL_ARMS uses the "throax.vtp" file, where as my model uses the "hat_ribs.vtp" file. When switching the MoBL_ARMS model to the hat_ribs.vtp file a similar thing happens where the offsets are no longer correct. Maybe the different toros geometries require different offsets?
Any help is greatly appreciated, I think I just need to figure out what the "torso_offset" needs to be so I can apply it to the joints and muscles. I attached a couple extra screenshots for reference.
Thanks,
Joe Marsh