A computer-implemented method for determining the porosity of a flexible porous structure when it is subjected to deformation, the flexible porous structure being a hollow structure made up of braided or non-braided wires, the method comprising performing the following steps by means of processing representative data of said flexible porous structure: a) generating a first function (F s) defining how at least one part of the flexible porous structure, given its coordinates, changes shape when it is subjected to one or more geometric deformations, wherein said change of the shape is determined in two directions, one in a cross-section of the flexible porous structure (F s1) and the other in a longitudinal direction (F s2); b) generating a second function (F p) defining how a covered surface, and/or a variable associated with same, for at least one part of the flexible porous structure, changes when it is subjected to one or more changes in shape, said second function (F p) being directly linked with porosity of the flexible porous structure; c) obtaining a tubular representation of the flexible porous structure in a reference configuration with known porosity, or reference porosity, values, and obtaining a tubular representation of the flexible porous structure in a deformed configuration different from said reference configuration; d) dividing the entire surface of the flexible porous structure into a set of deformed regions (CU-D); e) calculating, using the first function (F s), at least one reference region (CU-R) of the flexible porous structure in the reference configuration, wherein the reference region (CU-R) is equivalent to each of the deformed regions (CU-D); f) calculating the covered area in the reference region (CU-R) given the reference porosity in the reference region (CU-R); g) calculating the covered area of the deformed regions (CU-D) using the second function (F p) relating the covered areas in the deformed regions (CU-D) and the reference region (CU-R); and h) calculating the porosity of the deformed regions (CU-D) as the quotient between the non-covered area of the deformed regions (CU-D)and the total area of the deformed regions (CU-D), wherein the representative data of the flexible porous structure form respective three-dimensional representations of the flexible porous structure for each of the configurations: the reference configuration and the deformed configuration. a) generating a first function (F s) defining how at least one part of the flexible porous structure, given its coordinates, changes shape when it is subjected to one or more geometric deformations, wherein said change of the shape is determined in two directions, one in a cross-section of the flexible porous structure (F s1) and the other in a longitudinal direction (F s2); b) generating a second function (F p) defining how a covered surface, and/or a variable associated with same, for at least one part of the flexible porous structure, changes when it is subjected to one or more changes in shape, said second function (F p) being directly linked with porosity of the flexible porous structure; c) obtaining a tubular representation of the flexible porous structure in a reference configuration with known porosity, or reference porosity, values, and obtaining a tubular representation of the flexible porous structure in a deformed configuration different from said reference configuration; d) dividing the entire surface of the flexible porous structure into a set of deformed regions (CU-D); e) calculating, using the first function (F s), at least one reference region (CU-R) of the flexible porous structure in the reference configuration, wherein the reference region (CU-R) is equivalent to each of the deformed regions (CU-D); f) calculating the covered area in the reference region (CU-R) given the reference porosity in the reference region (CU-R); g) calculating the covered area of the deformed regions (CU-D) using the second function (F p) relating the covered areas in the deformed regions (CU-D) and the reference region (CU-R); and h) calculating the porosity of the deformed regions (CU-D) as the quotient between the non-covered area of the deformed regions (CU-D)and the total area of the deformed regions (CU-D),