The volumetric probe lets you specify a box-shaped region of space in which the magnetic field is calculated on a grid. Using the calculated field, you can create Level-set or Arrow plots.
A level set is a surface on which the chosen function has a specified value. Level set quantities include Ax, Ay, Az, A, Bx, By, Bz, B and f (the macro result). The Analog level adjustment slider lets you continuously adjust the level that is displayed.
The volumetric probe can also be used to make arrow plots of vector quantities. Available vector quantities are B and A.