Hello all, I am new to the CEM and I am interested in calculating RCS of electrically large body. I am going through the papers and i got confused with Geometrical optics and the raytracing. Although both works on ray principle, what is the difference between them? And also what is the difference between the (PO-GO-PTD) algorithm and (raytracing-PO-PTD) algorithm? I would be very thankful if anyone give clarity on this?