The extension of the Method of Auxiliary Sources (MAS) to large body scattering problems is investigated. Approximations leading to correct predictions of scattering field with minimum numerical cost are examined. After interpreting the involved physical phenomena associated with scattering field singularities, highly efficient MAS algorithms are developed. Furthermore, the same approach leads to a source visualization technique, which is of exceptional interest. As result of this analysis, an efficient "target" visualization method for large body scatterers, is proposed.