Point Inertia In 3Dx

Hello All, 

I'm looking to apply a point inertia in 3Dx, I've added the point at the center of mass of the abstracted body, and the mass, however for the mass moment of inertia values, I don't know what coordinate system they should be in respect to

  1. Should the I terms be added with respect to the model global coordinate system?
  2. Should the I terms be added with respect to the center of mass of the abstracted body?
  3. Does the axis system definition control which coordinate system to define I with respect to?

The user documentation isn't clear to me. Thanks!