Hello, I am a student and I am currently using AnyBody Modeling System. I have a C3D file obtained with a dataglove, and I'm wondering if I can read this file and analyze its data without having to model the hand.
Thank you
Hi,
Welcome to the AnyScript Forum!
This is definitely possible. If you don't want to include the human model, then you can simply make a main file and use AnyInputC3D class to read the c3d file.
Main = {
AnyInputC3D readC3D = {
FileName = "....c3d";
};
};
This will allow you to load and see the contents of the c3d file in AnyBody and you would be able to plot some of the outputs (like marker trajectories) in the ChartView.
I hope this helps.
Best regards,
Dave
Hello,
Thank you very much for your response.
I used the AnyInputC3D class but encountered an error message: "ERROR(OBJ.FILE1): MyHandModel.main.any(3): FileName: Problem with file: VMG.C3D: Failed to open the specified C3D file. Model loading skipped."
This means that the C3D file "VMG.C3D" could not be opened correctly during the model loading process.
Sincerely,
Djoher
Hi Djoher,
One reason this can happen is that the c3d file cannot be located. This could simply be because the file is located in another directory. I can see from the error message that the variable FileName is specified in your main file. Can you please confirm if your c3d file is located in the same folder as your main file? Can you please also share the code that you have written for FileName? It is also possible to specify another directory through the variable FileName. So it may be that the file in the same directory as the main file but the code specifies to look for the file in another directory.
Best regards,
Dave
Hello,
Thank you for your previous response that helped me visualize my data successfully. I have another question: can I use a full body model to perform an ergonomic analysis of the hand with my C3D data from the data glove?
In other words, I want to know if the full body model in AnyBody Modeling System can be used to specifically analyze the hand, even though my data only pertains to the hand and comes from a data glove.
Best regards,
Djoher
Hi Djoher,
It depends on what you want to analyze. There is an option of detailed hand model Detailed hand model — AMMR v3.0.1 Documentation. However, this just has the joints and no muscles. Each joint has a joint actuator. So, you can run some dynamics analysis but it is with some limitations.
Then, regarding the motion, it gets a little cumbersome. We don't have a model that does this and I can foresee some problems because you will have the marker information that will drive the hand to some position but you also need to somehow drive the rest of the human model to a sensible posture. Do you have some information about how you can drive the rest of the arm and the trunk? Is there a specific reason you want to run the full body model? At least, removing the legs will simplify the model a little bit.
Best regards,
Dave
Hello Sir,
My main objective is to perform an ergonomic analysis of hand movements in the context of a tightening task. I have obtained a C3D file containing hand motion capture data using a data glove.
I wish to analyze these hand movements in AnyBody Modeling System. My intention was to use the full body model as it includes the hand model.However, I do not need to analyze the other parts of the body, only the hand. My goal is to focus solely on analyzing the hand movements for this tightening task.Could you please guide me on the best way to proceed to load the data from the C3D file into AnyBody and specifically analyze the movements of the detailed hand model, without having to animate the full body?
Thank you in advance for your valuable assistance.
Sincerly,
Djoher
Hi Djoher,
When you talk about ergonomic analysis, are you also interested in looking at the forces through the hand? Or would kinematics be sufficient for your analysis?
There is another detailed hand model that is available. It's the Regensburg Ulm Hand model and you can find it on the AMMR available at github on a special branch. Please note that this works with AMMR 2.4.4 only at the moment. There is also a mocap model available in this branch in the Application/MocapExamples folder. The mocap model in the Regensburg hand model can be a good starting point for you since it also has several markers on the hand.
Since you have some mocap data for the hand it will be easier for you to get going with the Regensburg Hand model. This model has the trunk and the right arm only. And, if you start with your own model as well, then I will recommend you switch off the legs and one of the arms in the model through the BM statements. However, you will need to switch on the weak mannequin drivers in the ExtraDrivers file as you don't have mocap data for the arm or the trunk.
Depending on what's important for you and how much time you have, you can choose the Regensburg hand model or the Detailed hand model in AMMR (that has joint actuators only).
Regarding the tightening task, do you have some force or torque data that you want to apply to the hand? This can be a little bit cumbersome but I will wait for your reply before I elaborate on this.
Best regards,
Dave
Hello Dave,
I hope this message finds you well. I wanted to thank you for your previous message and the information you provided. Following our discussion, I would like to further explore the application of force data to the hand for my ergonomic analysis. Could you please guide me on the procedure to integrate this data into the Regensburg hand model?
Additionally, I was wondering if the user manual explains in detail how to deactivate parts of the model that are not of interest to me, such as the legs, and how to activate the weak mannequin drivers in the ExtraDrivers file. I would also like to know if there are any tutorials or additional resources that could assist me in this process.
Thank you in advance for your help and valuable advice. I am looking forward to implementing this information in my work.
Best regards,
Djoher
Hi Djoher,
What kind of force data do you have? Can you explain a little bit about that, please? Normally, you would need to use contact elements, like we do in ground reaction force prediction, but you would need more complicated setup.
Please see this tutorial on how to adjust the body model. There is a Body Model configuration file in every model where you can type in some statements to configure the body model: if you want a specific body part or no, if you want muscles or no, etc. You can find a list of all the parameters over here. Normally, you can also do this by the body model configuration plugin. You can find this plugin over here in a loaded model.
For setting up your mocap model, please see this wiki page. This is more general and your application is a little bit specific. You can access the ExtraDrivers.any file through the LabSpecificData.any file. Over there, you can see some documentation and example of how to set weak mannequin drivers. Here, you can find a list of all the mannequin drivers available in AMMR.
I hope this helps.
Best regards,
Dave