A METHOD OF PRINTING AN INTERIOR INFILL USING A 3D PRINTER

The invention relates to a method of printing an interior infill using a 3D printer. The method comprises the steps of: defining a planar first infill pattern (11) of lines having a first cross-sectional width; defining a planar second infill pattern (12) of lines having a second cross-sectional width; defining a planar transitional infill pattern (13) of lines having a third cross-sectional width exceeding the first cross-sectional width and the second cross-sectional width; and printing a first set of layers of the first infill pattern, a transitional set of layers of the transitional infill pattern, and a second set of layers of the second infill pattern such that the transitional set of layers is printed between the first set of layers and the second set of layers. The invention further relates to an article having a layered interior infill and a computer system for designing an interior infill of an article.