I am new to Sim4Life and am just wondering how I can sense voltages or current density on electrodes.

Currently I am placing a current dipole in the grey matter using the electro ohmic quasistatic solver and the boundary flux option. The positive source is deeper in the head while the negative source is closer to the surface of the skin.

I am then setting another boundary on the side of the head at 0V. I want to be able to sense the dipole on the back of the head using an Oz skin-invasive electrode, which I have already set up. Should I voxel the head and electrode together? And how do I sense current density? I have been putting a plane that cuts the electrode in its cross section and using flux evaluation but I get a 0 reading.

Thank you for any advice!