The present work aims to analyse the behaviour of thin or shallow shells in order to find a simple way for defining quantitatively the concept of Funicularity. The first mention in the scientific literature about the condition of Funicularity was due to Dermot O’Dwyer, who describe the funicular analysis of masonry vaults.He started by studying arches in which the stress state can be represented with a line of thrust defined by a funicular polygon. This calculation procedure becomes more difficult when we deal with 3-D structures like shells. He proposes a method to evaluate the surface of thrust and to determinate the ultimate load of collapse This method consists of seven different steps that allow to find the force network by imposing two sets of constraints: the first is related to the height of the structural nodes that should lie into the thickness of the element; the second set of constraints concerns the vertical equilibrium of the forces in each node.