Electric field línes in matlab.

Hello matlabbers.

I am working on a physical problem which is to integrate the induced charge on an electrode by some electrons that are within the electric field and drift toward one of the electrodes which are creating the electric field.

I have been able to solve this in the case of an infinite and finite parallel plate type structure as the electric file is constant (as is the weighting field.). However when I begin segmenting one of the parallel plates into pieces, the electron drift is no longer linear but has some trajectory normal to the ISO-potential lines of the electric field . The electric field has curvature because the electrodes are different size.

I am simulating a 3d electric Field, and I have about 100 segmented pixels on one side and plan at electrode on the other. I can solve for the electric field and for the weighting field. My question is how you define a trajectory of the electron in my 3d array so that it follows the correct path I,e, least action?