What does pattern function do under planeWaveExcitation?

I have a question regarding planeWaveExcitation.

When I create a planeWaveExcitation environment:

p = planeWaveExcitation;
p.Direction     = [0 0 1];
p.Polarization  = [0 1 0];
p.Element       = myArray;

and then I call the pattern() or patternElevation() function:

patternElevation(p, freq);

what is MATLAB actually doing here? Am I actually obtaining a scattering solution for the radiation pattern (i.e. plane wave comes in, excites currents in my element, then re-radiates fields that result in the radiation pattern I am shown), or is something else going on?

I'm also interested in any nuance between using an element vs array as the planeWaveExcitation 'Element.'

Thank you in advance.