A method for layer-by-layer production of a three dimensional object is provided. The method includes applying a layer of a polymer powder having a thickness; selectively irradiating portions of the polymer powder layer with a laser beam having an average power density and a focus maximum power density to melt and sinter the irradiated polymer powder; cooling the melted and sintered powder to obtain a solid mass having a shape; and repeating the application, irradiating and cooling operations until the three dimensional object is obtained; wherein a duty factor of the laser beam is greater than 60%. Also provided is an apparatus to carry out the method and a molding obtained therefrom.