1. A method for controlling a graphical interface for displaying images of a three-dimensional object, comprising: providing an array of magnetometers comprising N three-axis magnetometers mechanically connected to one another with no degree of freedom to conserve a known distance between each of the magnetometers, wherein N is an integer number greater than or equal to five, the array of magnetometers being associated: with a working three-dimensional reference frame whose position is known with respect to the array of magnetometers, and with a predetermined three-dimensional measurement area; recording a digital file coding dimensions of the three-dimensional object in a three-dimensional reference frame as a virtual reference frame, a position of the virtual reference frame with respect to the working reference frame being known such that coordinates of each point of the virtual reference frame may be expressed in the working reference frame by a change of reference frame; providing a pointer comprising a permanent magnet manually moveable by a user inside of the measurement area; measuring, when the permanent magnet is placed inside of the measurement area, by the magnetometers of the array, the magnetic field generated by the permanent magnet; calculating coordinates of the permanent magnet and of a direction of the magnetic moment of the permanent magnet in the working reference frame based on the measurements of the magnetometers; matching the dimensions of the three-dimensional object with the coordinates previously calculated by multiplying each dimension of the three-dimensional object by a coefficient C v to obtain a three-dimensional object brought to scale and by multiplying the coordinates calculated by inverse of a coefficient C R to obtain coordinates to scale, wherein the coefficients C v and C R are chosen such that the ratio C V /C R is equal to a scaling coefficient C e , the coefficient C e being strictly less than d Z /d max , wherein: d max is the distance between the origin of the working reference frame and the point of the three-dimensional object furthest from the origin along a measurement axis, and d Z is the distance between the origin of the working reference frame and the point of the measurement area furthest from the origin along the same measurement axis, the measurement axis retained being the axis going through the origin of the working reference frame and for which the difference |d max −d Z | is maximized, constructing an image in two dimensions corresponding to the image of the object brought to scale observed from a viewing point and along a predetermined optical axis, the position of the viewing point being deduced from the coordinates to scale, and the direction of the optical axis being deduced from the measured direction of the magnetic moment of the permanent magnet; and controlling the graphical interface to display the image constructed on the graphical interface.