Curved surfaces have not been thoroughly considered in radiative transfer analysis mainly due to the difficulties arising from the integration process and perhaps because of the lack of spatial vision of researchers. When dealing with them, application of the iterative method or direct calculation through integration does not provide with an exact solution, so that only approximate expressions or tables are given for a very limited number of forms [1]. In this way, a vast repertoire of significant shapes remains neglected and energy waste is evident. For this reason, further research on the matter, starting from a different approach was considered worth doing.

In previous researches from the authors, form factor calculation has been undertaken for several types of emitters. In all cases, geometric properties of those, revealed as the most powerful tool that shapes radiant interchange [3, 4, 5, 6]. This included mainly rectangular shapes, plane forms and the volumes that can be composed with such primary geometries.