issue on cm position, segment mass and segment inertia after joining

Hi Martin,

Looks to me like this problem is arising because you are using the option to Define Mass By: Geometry and Material Type.  Then when you build your joints, the joint geometry (that blue ellipsoid) is being included in the mass calculation (since it is just another geometry object, afterall) and changing those calculated mass properties. You can still use this material type calculation method with a single additional step. Before you build your joints (so starting at the screenshot on the left):

1. Specify your desired material and hit apply; it calculates all of these mass properties

2. In the "Define Mass By" field, select "User Input". This will save the values that you just calculated, but it will not recalculate them going forward

3. Now build your joints.  The additional geometry (knee bubble) should no longer be included in the mass calculation, and the mass properties should remain unchanged.

Note that in a standard LifeMOD model, the "Create Base Joint Set" will do this automatically. its only the case of nonstandard joint creation (from the "Create Individual Joint" panel) that the "Define Mass By" field should be manually set back to "User Input". 

Hopefully this solves your problem, please do not hesitate to let us know if you have any additional questions or concerns!