Further progress with fast and reliable shadowing determination for mesh-based PO analysis

The physical optics (PO) approximation is commonly used for scattering analysis of objects represented by a mesh of triangle elements. For PO-based analysis the shadowing information of each triangle with respect to the illumination is required (point source or plane wave). This task can be efficiently performed by splitting up the field of view into buffer boxes to localize shadowing checking. This works very well, except that inhomogeneous meshes and grazing incidence can have severe adverse effects upon computational efficiency. Further progress toward obtaining an algorithm which may generally be regarded as of O(N) complexity with provision for efficient, robust handling of extreme mesh inhomogeneity and grazing incidence is presented in this paper.