Differential View Factor for a Rectangle with Intervening Parallelepiped or Sphere

Thermal radiation determines the temperatures attained by a surface in an enclosure having several objects, especially in space applications. Because of the geometrical complexities, the analytical determination of net radiation heat transfer from/to a surface is mathematically very difficult. To make the mathematical analysis feasible, the interior objects are often modeled into appropriate primitives such as parallelepipeds and spheres.