Inertia of a body split into two parts?

[Pagnon David]

Hello,

A few questions about inertia and mass centers in OpenSim:

1- Where do you get mass centers and inertias for your OpenSim models? Do you just find them in anthropometric tables such as Zatsiorski's, Leva's, or Nikolova's? I couldn't find the right references for the bones I was looking for.

2- Do you calculate them from the shape of the bones? Is there a tool for it? But then, there is no flesh so I don't see how inertia could be accurate, especially on the torso or on thick limbs such as thighs.

3- I want to split a body in two parts, let's say {head+torso}, into {head} and {torso}? How do you calculate mass center and inertia of each of the resulting parts then?

Thank you!

[Pagnon David]

Hello, I'm allowing myself to ask again, since I haven't figured it out yet.

I have a body (namely {head+torso}, with defined inertia, mass center, mass) that I want to split into two parts ({head} and {torso}). I don't know how to calculate their respective inertia.

How would one do this?