1. A method of producing a finite-element model of a unique body of complex shape having an outer surface that is known in the form of a cloud of points describing said surface analytically or algebraically in a determined frame of reference, comprising the steps of: a) using a generic and parameterizable finite-element model, the model being made up of simple geometrical volumes that are representative of the family to which the unique body belongs; b) adapting the model as a function of parameters describing the unique body that is to be modeled; c) within the frame of reference, adjusting the position and/or the parameterization of the generic finite-element model and causing the surface nodes of the parameterized model to correspond with points of the known outer surface of the body by projecting said nodes onto said surface along a direction that is normal to the surface of the generic model; and d) using the nodes of the surface as control points in a three-dimensional interpolation method in order to personalize the internal finite elements of the generic model.