A data processing device for manufacturing orthotropic foam, comprising a memory arranged to receive location data designating a location and a volume element containing this location, and a generator arranged to determine additive manufacturing data indicating if a location associated with the location data is empty or full, characterized in that: - the memory is arranged to receive density data, deformation data and radius data, and in that - the generator (4, 10) is arranged to calculate, for a given location designated by location data, branch grain data designating locations of branch grains of a set of branch grains associated with the given location, - the generator is arranged to determine said branch grain locations in a plurality of volume elements comprising the volume element containing the given location on the one hand and volume elements selected in a vicinity of the volume element containing the given location on the other hand, each volume element receiving a number of branch grains drawn from density data associated with this volume element, the orthotropic foam being built by connecting these branch grains to each other, - the generator (4, 10) is also arranged to calculate a measurement between a first branch grain and a second branch grain from the distance between the location of the first branch grain on the one hand and the second branch grain on the other hand, by weighting this distance as a function of deformation data associated with the first branch grain and with the second branch grain, - the generator (4, 10) is also arranged to select at least two branch grains for each branch grain, such that these at least two branch grains are the closest neighbors according to the measurement calculated by the generator (4, 10), and - the generator (4, 10) is also arranged to define manufacturing data indicating that a location is full when the distance between said location and its projection on one of the branches linking each branch grain to its closest neighbors is less than a distance drawn from the radius data. - the memory is arranged to receive density data, deformation data and radius data, and in that - the generator (4, 10) is arranged to calculate, for a given location designated by location data, branch grain data designating locations of branch grains of a set of branch grains associated with the given location, - the generator is arranged to determine said branch grain locations in a plurality of volume elements comprising the volume element containing the given location on the one hand and volume elements selected in a vicinity of the volume element containing the given location on the other hand, each volume element receiving a number of branch grains drawn from density data associated with this volume element, the orthotropic foam being built by connecting these branch grains to each other, - the generator (4, 10) is also arranged to calculate a measurement between a first branch grain and a second branch grain from the distance between the location of the first branch grain on the one hand and the second branch grain on the other hand, by weighting this distance as a function of deformation data associated with the first branch grain and with the second branch grain, - the generator (4, 10) is also arranged to select at least two branch grains for each branch grain, such that these at least two branch grains are the closest neighbors according to the measurement calculated by the generator (4, 10), and - the generator (4, 10) is also arranged to define manufacturing data indicating that a location is full when the distance between said location and its projection on one of the branches linking each branch grain to its closest neighbors is less than a distance drawn from the radius data.