A method for producing a digital representation for manufacturing an appliance adapted to an object forming at least one portion of a living body, comprising: receiving a first three-dimensional model of the internal and external structure of the object in a first three-dimensional frame of reference, receiving a second three-dimensional model of the appliance to be manufactured defining at least one set of functional areas characteristic of the appliance and optionally a contour of the appliance, the second model comprising data representative of: - coordinates in a second three-dimensional frame of reference of edge points forming part of the edge of a functional area and vertex points representing vertices of a functional area, - a value of a deformation parameter, representative of the deformation of the functional area, associated with each vertex point, - optionally, coordinates in the second frame of reference of points or contour lines of the appliance, changing the second model by applying a transformation matrix, which expresses the coordinates of these points in the first frame of reference, to the points of the model, the transformation matrix being calculated so as to match characteristic reference marks of the internal structure of the object to be fitted defining the second frame of reference of the second model with the same characteristic reference marks present in the first model, calculating for each functional area of the second model: - an edge curve passing through the edge points, - a vertex curve passing through the vertex points, transferring, onto the first model, the edge curves, the vertex curves and the deformation parameter values associated with each vertex point of the second model, in order to position the edge curves and the vertex curves taking into account the values of the deformation parameters for the latter and optionally the contour points or lines of the appliance, onto the outer envelope of the first model, deforming the outer surface of the first model depending on the vertex curves to conform the outer surface of the first model to the shape of the second model in each functional area and obtain a first corrected model, optionally, displaying a graphical representation of the first corrected model, saving the first corrected model in a computer memory as a final model. receiving a first three-dimensional model of the internal and external structure of the object in a first three-dimensional frame of reference, receiving a second three-dimensional model of the appliance to be manufactured defining at least one set of functional areas characteristic of the appliance and optionally a contour of the appliance, the second model comprising data representative of: - coordinates in a second three-dimensional frame of reference of edge points forming part of the edge of a functional area and vertex points representing vertices of a functional area, - a value of a deformation parameter, representative of the deformation of the functional area, associated with each vertex point, - optionally, coordinates in the second frame of reference of points or contour lines of the appliance, - coordinates in a second three-dimensional frame of reference of edge points forming part of the edge of a functional area and vertex points representing vertices of a functional area, - a value of a deformation parameter, representative of the deformation of the functional area, associated with each vertex point, - optionally, coordinates in the second frame of reference of points or contour lines of the appliance, changing the second model by applying a transformation matrix, which expresses the coordinates of these points in the first frame of reference, to the points of the model, the transformation matrix being calculated so as to match characteristic reference marks of the internal structure of the object to be fitted defining the second frame of reference of the second model with the same characteristic reference marks present in the first model, calculating for each functional area of the second model: - an edge curve passing through the edge points, - a vertex curve passing through the vertex points, - an edge curve passing through the edge points, - a vertex curve passing through the vertex points, transferring, onto the first model, the edge curves, the vertex curves and the deformation parameter values associated with each vertex point of the second model, in order to position the edge curves and the vertex curves taking into account the values of the deformation parameters for the latter and optionally the contour points or lines of the appliance, onto the outer envelope of the first model, deforming the outer surface of the first model depending on the vertex curves to conform the outer surface of the first model to the shape of the second model in each functional area and obtain a first corrected model, optionally, displaying a graphical representation of the first corrected model, saving the first corrected model in a computer memory as a final model.