Partially overlapped segment issue in Lower Extremity model

Hello, AnyBody Team.

Currently, I'm practicing a lower extremity model from AMMR.

I found that some segments partially overlap such as the tibia and talus and between the fibula and talus in the basic lower extremity model.

I'm considering that this issue occurred when making reference frames and points in the segments.
(Since the reference frame and points are established based on the ISB coordinate system, the segments are considered shifted and overlapping in the lower extremity model.)

Please check this issue and let me know.

Thank you

Best regards,
Donghwan Lee

Hi Donghwan Lee,

I don't see overlap between the talus and the shank (tibia and fibula). However, I do acknowledge the overlap between the talus and the foot (calcaneus and navicular).

This is not ideal, and I can't be sure where the error comes from. The data for this model comes from the TLEM 2.0 dataset and this could be due to the definition of joint axes, or scans of the bones, a little bit of both, or something else altogether? I can't really say...

At the moment, we are working on making new foot models in the AMMR using the GM foot model dataset. It's not ready yet but you can request access to AMS beta to have early access when it's available.

Best regards,
Dave

1 Like

Hi Dave,

Thank you for your explanation.

I don't mean that the tibia and fibula are overlapped. You can find the fibula and talus are also slightly overlapped in the LowerExtremity model.

By the way, I checked the GM foot model (download from Github), but it has the same problems (fibula and talus are overlapped.). I recommend you check this in the GM foot model for making new foot models.

However, this problem is not only for the AnyBody Modeling System. I also found this problem in the OpenSim gait 2392 model.

At the moment, I'm re-modeling the LowerExtremity model for avoiding this problem. I hope you notify this issue to AnyBody users for better understanding.

Best regards,
Donghwan Lee

Hi Donghwan,

For sure, we are keeping an eye on this issue.

This is not such a trivial issue, especially when you try mix and match GM foot with TLEM leg. You are trying to match datasets from different subjects, with different bone geometries and anthropometry.

Maybe we can discuss what exactly are your needs from the model and find out if there are some synergies in the work we are doing?

Best regards,
Dave

1 Like

Hi Dave,

Matching datasets from subjects in comparison with different bone geometries and anthropometry is one of my interests; however, that's a little later.

By the way, I found an error code in the GM foot model, and then I'm telling you.

In the 'LigParms.any' file, a1 is equal to '.LigParms.a0'. But it should be equal to '.LigParms.a1'.
(* Directory: gm-foot-master -> FootGM -> LigParms.any)
Maybe you need to fix this error for making new foot models in the AMMR using the GM foot model dataset.

Best regards,
Donghwan Lee

Hi Donghwan,

Thanks for pointing it out. That does look like a bug. I have noted this and we will review it!

Best regards,
Dave

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