A method of manufacturing a three-dimensional object by additive layer manufacturing, comprising the following steps: successively providing a plurality of layers of material in powder form, one on top of the other, on a support means, wherein the material in powder form is or comprises polymer material, and irradiating each layer, prior to providing the subsequent layer, with at least one laser beam or particle beam using at least one irradiation device, wherein each layer is irradiated selectively only in those portions of the layer corresponding to the three-dimensional object being manufactured and wherein the irradiation is carried out in such a manner that the material is melted locally in the corresponding portions, wherein the temperature of the layers is controlled such that prior to irradiation of each layer the respective layer has a starting temperature which is in a range from the glass transition temperature of the polymer material to 30% above the glass transition temperature, and wherein for each layer the irradiation is carried out in such a manner that each location of those portions of the layer corresponding to the three-dimensional object being manufactured is irradiated multiple times during multiple spaced time intervals associated with the respective location, wherein operating parameters of the at least one irradiation device are chosen such that in each of the locations the polymer material reaches the melting temperature only during or after the second or a subsequent one of the time intervals associated with the respective location and that in each of the locations the energy introduced during each of the associated time intervals by the at least one laser beam or particle beam is insufficient to heat the polymer material from the starting temperature to the melting temperature of the polymer material. successively providing a plurality of layers of material in powder form, one on top of the other, on a support means, wherein the material in powder form is or comprises polymer material, and irradiating each layer, prior to providing the subsequent layer, with at least one laser beam or particle beam using at least one irradiation device, wherein each layer is irradiated selectively only in those portions of the layer corresponding to the three-dimensional object being manufactured and wherein the irradiation is carried out in such a manner that the material is melted locally in the corresponding portions, wherein the temperature of the layers is controlled such that prior to irradiation of each layer the respective layer has a starting temperature which is in a range from the glass transition temperature of the polymer material to 30% above the glass transition temperature, and wherein for each layer the irradiation is carried out in such a manner that each location of those portions of the layer corresponding to the three-dimensional object being manufactured is irradiated multiple times during multiple spaced time intervals associated with the respective location, wherein operating parameters of the at least one irradiation device are chosen such that in each of the locations the polymer material reaches the melting temperature only during or after the second or a subsequent one of the time intervals associated with the respective location and that in each of the locations the energy introduced during each of the associated time intervals by the at least one laser beam or particle beam is insufficient to heat the polymer material from the starting temperature to the melting temperature of the polymer material. <EOS>