I have encountered some uncertainties while using the Plug-in-gait_Simple model library, specifically the LowerExtremity.main model. I hope that you can spare some time to answer my questions, and I would be immensely grateful for your assistance.
Question 1: The template includes three force plates, but my experimental environment does not have any force plates, and the C3D file does not contain the corresponding data. Do I need to comment out the code related to the force plates to ensure the analysis is conducted correctly? Or can the model automatically detect the presence or absence of force plate data when reading the C3D file, rendering the force plate code ineffective if no related information is available?
Question 2: Based on the premise of Question 1 (if it is necessary to comment out the force plate-related code), I would like to obtain the predicted ground reaction force. It seems that the default code in the model already includes this functionality. Do I need to further modify the relevant parts of the model code to achieve this?
Hi James,
Here are some answers:
1: You will need to out comment the forceplates otherwise the model will try to look for data in the C3D file which is not there.
2: In the repository there are models already setup up to do GRF prediction see e.g. Simple GRF prediction model — AMMR v3.0.4 Documentation (anyscript.org)
This model has settings that disable forceplates and replace them by GRF prediction. This is done through the use of "USE_GRF_PREDICTION" which has been define in that model. Note that for this to work you will need full-body marker-protocol.
I sincerely appreciate you taking the time out of your busy schedule to answer my previous questions. Your insights have been incredibly helpful. However, I have encountered a new issue.
During my motion capture recording, I only placed markers on the lower limbs of the subject and recorded a C3D file while the patient walked. Consequently, I had to comment out the markers for the spine and head, such as C7 and T10, in the Markprotocol.any file. Although the model did not report any errors during computation, the Model View displayed unnatural movements of the upper body due to the lack of marker-driven inputs for these regions.
To ensure that I can drive the entire body's normal motion using only the lower limb markers, I believe it is necessary to lock certain movements of the lumbar and cervical spine. I attempted to modify the joint driver code in BodyModel.config_info.any and BodyModel.defaults.any, but this did not seem to have the desired effect. I am using the LowerExtremity.any model from the Mocap Examples folder and have not made any changes other than in the Markprotocol file.
Could you please advise me on which specific code I should modify to achieve my goal?
You can switch on the mannequin drivers for the trunk and neck. Please see this link for the statements that you will need. You can add these statements in the ExtraDrivers.any file that you can access through the LabSpecificData.any file.
