It is well known that the software Surface Evolver (SE) models the geometry of minimal surface area structures such as a foam. Here we have modelled with SE the gas-diffusion phenomenon responsible for the coarsening of liquid foams. We took as an initial condition, a real reconstructed foam obtained by optical tomography by Monnereau and Vignes-Adler (MVA) which is made of 148 bubbles of which 28 are internal. The MVA foam was reconstructed at different times, and a coarsening law was proposed. In this paper, the numerical and real volume evolutions of each bubble are analysed in the framework of an equivalent of the three-dimensional Von Neumann law and found to be identical. Also the cases of one free bubble and two bubbles are presented to determine the best numerical procedure to achieve the diffusion under SE.