Hi, I'm wondering if anyone has any sources for off-axis point calculation for multiple current carrying loops that contain a soft iron core. I have been using this resource so far and I can figure out how to include multiple loops. How would I approach these calculations with an iron core inside of the loop? EDIT: the resource is http://www.netdenizen.com/emagnet/offaxis/iloopoffaxis.htm In the off-axis calculation it uses the original B which would be inside of 1 loop of wire. So I'm wondering if adding an iron core to the center would be the equivalent to multiplying the entire equation by the permeability constant?