A method of digitally reconstructing a representative volume element of microstructure of a composite material for the fabrication of composite materials, the method comprising: • a definition step for defining a volume element; • a packing step for packing the defined volume element with a plurality of digital elements modelling fiber elements of the composite material, each digital element extending longitudinally along a main axis, this packing step comprising: • an association step for associating each digital element with a position in a determined plane in three-dimensional space and with an orientation of its main axis in that plane; and • a positioning step for successively positioning each digital element in the volume element in compliance with the position and the orientation that are associated therewith, this positioning step comprising putting the digital element into contact with at least one wall of the volume element and/or at least one previously-positioned digital element, and geometrically adapting the digital element to said at least one wall and/or to said at least one previously-positioned digital element with which it is in contact; at least a portion of a digital element used for packing the volume element being subjected during the geometrical adaptation to a deformation other than having its longitudinal axis inclined relative to the main axis of the digital element, said method further comprising a discretization step (F10, F30) for discretizing the volume element and each digital element in uniform manner into a plurality of voxels, and the geometrical adaptation comprising positioning at least two subsets (C2-C1, C2-2) of voxels of the digital element in planes in three-dimensional space that are vertically offset relative to each other. • a definition step for defining a volume element; • a packing step for packing the defined volume element with a plurality of digital elements modelling fiber elements of the composite material, each digital element extending longitudinally along a main axis, this packing step comprising: • an association step for associating each digital element with a position in a determined plane in three-dimensional space and with an orientation of its main axis in that plane; and • a positioning step for successively positioning each digital element in the volume element in compliance with the position and the orientation that are associated therewith, this positioning step comprising putting the digital element into contact with at least one wall of the volume element and/or at least one previously-positioned digital element, and geometrically adapting the digital element to said at least one wall and/or to said at least one previously-positioned digital element with which it is in contact; at least a portion of a digital element used for packing the volume element being subjected during the geometrical adaptation to a deformation other than having its longitudinal axis inclined relative to the main axis of the digital element, said method further comprising a discretization step (F10, F30) for discretizing the volume element and each digital element in uniform manner into a plurality of voxels, and the geometrical adaptation comprising positioning at least two subsets (C2-C1, C2-2) of voxels of the digital element in planes in three-dimensional space that are vertically offset relative to each other. • an association step for associating each digital element with a position in a determined plane in three-dimensional space and with an orientation of its main axis in that plane; and • a positioning step for successively positioning each digital element in the volume element in compliance with the position and the orientation that are associated therewith, this positioning step comprising putting the digital element into contact with at least one wall of the volume element and/or at least one previously-positioned digital element, and geometrically adapting the digital element to said at least one wall and/or to said at least one previously-positioned digital element with which it is in contact; at least a portion of a digital element used for packing the volume element being subjected during the geometrical adaptation to a deformation other than having its longitudinal axis inclined relative to the main axis of the digital element, said method further comprising a discretization step (F10, F30) for discretizing the volume element and each digital element in uniform manner into a plurality of voxels, and the geometrical adaptation comprising positioning at least two subsets (C2-C1, C2-2) of voxels of the digital element in planes in three-dimensional space that are vertically offset relative to each other.