An adaptive facet subdivision scheme for the shadowing culling of large and complex targets

An adaptive facet subdivision scheme which is suitable for the shadow culling of large and complex objects is presented. Unlike the pre-meshing method by fine meshing the object to reduce the shadowing error; in the proposed scheme, the shadowing is culled by adaptively subdividing the triangular facets along the boundary of the shadow and no shadowing error remained. By applying the scheme recursively, beside the incident shadowing, the shadowing caused by any order multiple reflection can be calculated. The adaptive facet subdivision only occurs in the process of scattering electromagnetic field calculation, and the pre-meshing of the target surface is not necessary. The proposed scheme provides precisely facet subdivision, minimum computer resource requirements and convenient run-times.