Calculation of the porosity of the segmented coating volume was based upon the pore volume distribution and maximum inscribed sphere distribution.
Although the pore volumes show a broad range, the radii of the maximum inscribed sphere arc limited due to the irregular shape of most pores.
A particularly opulent example was owned by Federigo da Montefeltro, perhaps inspiring him to include Ptolemy in the famous men of his Studiolo; another was presented, together with an inscribed sphere
, to Rene d'Anjou, King of Naples, then living in France, by Jacopo Antonio Marcello of Venice, then Governor of Padua.
This rules-based computer program incorporates chemistry, pouring temperature, casting weight, inscribed sphere
, mold hardness, riser location and riser type.