Calculation of Radar Cross Section (RCS) of arbitrary bodies using Physical Optics (PO) Theory and Physical Theory of Diffraction (PTD)is considered. For bodies with impedance surface boundary condition, only PO is used. Analytical approach to PO integral is used to achieve faster computations. A computer program has been developed in Fortran in order to calculate the Radar Cross Section (RCS). Arbitrary shape is modeled as triangular facets of any area by the help of graphical tools. Given the triangular meshed model of an arbitrary body, Physical Optics(PO) surface integral is numerically evaluated over the whole surface. There is no limitation on the size of the triangles, as soon as the total surface does not retire from the original one. Shadowing algorithm has been used in order to have more accurate solutions. Additionally, flash points of PO are visualized over the surface of targets, hence local nature of high-frequency phenomena is proved. Induced surface currents, edge currents and RCS have been calculated for some basic shapes and the fuel tank model of F-16 airplanes. Induced surface currents have been visualized over the surface of the particular targets using Matlab.