Dear OpenSim experts:
We are using OpenSim to test an ankle-foot orthosis during walking and running. And now we have several questions about the virtual markers and marker registration during scaling which confused us a lot (we have watched the "OpenSim Webinar: Tips and Tricks for Data Collection, Scaling and Inverse Kinematics in OpenSim" but still have such confusion):
(1) For scaling the body, we noticed that some models just used anatomic markers to scale the body (e.g. the gait2392 model used RASIS marker and Right Lateral Knee marker to scale the thigh), but some other models used anatomic markers and virtual markers to scale the body (e.g. the Rajagopal model used Right Hip Joint center,Left Hip joint center, Right Lateral Knee marker and Left Lateral Knee marker to scale the thigh). We are just wondering how important it is to use the virtual markers for scaling, for example using the virtual markers to scale the body will significantly improve the accuracy of the prediction?
(2) For the marker registration during scaling, we noticed that in some of the models, the anatomic markers are not fixed (e.g. in the gait 2392, the anatomic markers are not fixed (false)), but in some other models, the anatomic markers are fixed (e.g. in the Rajagopal model, the anatomic markers are fixed (for walking simulation)). So we are just wondering whether we need to fixed the anatomic markers during the scaling, and what are the effects if the anatomic markers are not fixed during the scaling?
Sorry for so long questions. We would appreciate it if some one can explain these and provide suggestions to us, which will help us a lot for using the OpenSim. Thanks in advance.
Best regards
Xijin